U.S. patent application number 10/279701 was filed with the patent office on 2003-09-04 for colorimetric artificial nose having an array of dyes and method for artificial olfaction.
This patent application is currently assigned to Board of Trustees of the University of Illinois. Invention is credited to Suslick, Kenneth S..
Application Number | 20030166298 10/279701 |
Document ID | / |
Family ID | 27063746 |
Filed Date | 2003-09-04 |
United States Patent
Application |
20030166298 |
Kind Code |
A1 |
Suslick, Kenneth S. |
September 4, 2003 |
Colorimetric artificial nose having an array of dyes and method for
artificial olfaction
Abstract
The present invention involves an artificial nose comprising an
array, the array comprising at least a first dye and a second dye
deposited directly onto a single support in a predetermined pattern
combination, the combination of dyes in the array having a distinct
and direct spectral absorbance or reflectance response to distinct
analytes comprising one or more parent analytes or their
derivatives. In one embodiment, the invention further comprises an
oxidizing source to partially oxidize at least one distinct parent
analyte to at least one corresponding derivative analyte of said
parent analyte, the array at least in part having a stronger
distinct and direct absorbance or reflectance response to the
derivative analyte than to the corresponding parent analyte.
Inventors: |
Suslick, Kenneth S.;
(Champaign, IL) |
Correspondence
Address: |
BANNER & WITCOFF, LTD.
TEN SOUTH WACKER DRIVE
SUITE 3000
CHICAGO
IL
60606
US
|
Assignee: |
Board of Trustees of the University
of Illinois
601 East John Street
Champaign
IL
61820
|
Family ID: |
27063746 |
Appl. No.: |
10/279701 |
Filed: |
October 24, 2002 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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10279701 |
Oct 24, 2002 |
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09705329 |
Nov 3, 2000 |
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6495102 |
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09705329 |
Nov 3, 2000 |
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09532125 |
Mar 21, 2000 |
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6368558 |
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Current U.S.
Class: |
436/169 ;
422/400; 422/90 |
Current CPC
Class: |
G01N 21/272 20130101;
G01N 21/78 20130101; G01N 31/22 20130101 |
Class at
Publication: |
436/169 ; 422/90;
422/58 |
International
Class: |
G01N 031/22 |
Goverment Interests
[0002] This invention was made with Government support under
Contract Nos. HL25934 awarded by the National Institutes of Health
& Contract No. DAAG55-97-1-2211 awarded by the Department of
the Army. The Government has certain rights in the invention.
Foreign Application Data
Date |
Code |
Application Number |
Mar 21, 2001 |
WO |
PCT/US01/09092 |
Claims
What is claimed is:
1. An artificial nose comprising an array, the array comprising at
least a first dye and a second dye deposited directly onto a single
support in a predetermined pattern combination, the combination of
dyes in the array having a distinct and direct spectral absorbance
or reflectance response to distinct analytes comprising one or more
parent analytes or their derivatives, and an oxidizing source to
partially oxidize at least one distinct parent analyte to at least
one corresponding derivative analyte of said parent analyte, the
array at least in part having a stronger distinct and direct
absorbance or reflectance response to the derivative analyte than
to the corresponding parent analyte.
2. The artificial nose of claim 1, wherein the at least one
distinct parent analyte is from the group consisting of organic
compounds lacking ligatable functionality and molecules sterically
hindered as to preclude effective ligation, acid-base interaction
functionality, hydrogen-base interaction functionality, and dipolar
interaction functionality.
3. The artificial nose of claim 1, wherein the at least one
corresponding derivative analyte has a stronger interaction with at
least part of the array than its corresponding parent analyte.
4. The artificial nose of claim 3, wherein the stronger interaction
is from the group consisting of ligation interaction, acid-base
interaction, hydrogen-base interaction, and dipolar
interaction.
5. The artificial nose of claim 1, wherein the oxidizing source
comprises an oxidation catalyst.
6. The artificial nose of claim 5, wherein the oxidation catalyst
from the group consisting of noble metals, noble metal oxides,
early transition metals oxides and metal-containing microporous
zeolites.
7. The artificial nose of claim 5, wherein the oxidation catalyst
is contained in a cartridge.
8. The artificial nose of claim 1, wherein the oxidizing source is
from the group consisting of substantially pure oxygen, air,
hydrogen peroxide, hypochlorite, chlorine dioxide, chlorine or
other bleaching agents.
9. The artificial nose of claim 5, wherein the oxidation catalyst
is from the group consisting of platinum, palladium, and vanadium
oxide.
10. The artificial nose of claim 5, wherein the partial oxidation
of the at least one distinct analyte is conducted in a temperature
range of between 100 K and 1000 K.
11. The artificial nose of claim 1, wherein the at least one
derivative analyte is from the group consisting of alcohols,
aldehydes, ketones, carboxylic acids, carbon monoxide, and carbon
dioxide.
12. A method of detecting at least one parent analyte comprising
the steps of (a) forming an array by depositing at least a first
dye and a second dye directly onto a single support in a
predetermined patter combination, the combination of dyes in the
array having a distinct and direct spectral or reflectance response
to distinct analytes comprising one or more parent analytes or
their derivatives, (b) partially oxidizing the at least one parent
analyte to form at least one derivative analyte corresponding to
said parent analyte, (c) subjecting the array to the at least one
derivative analyte, and (d) inspecting the first dye and the second
dye for a direct and distinct spectral response corresponding to
the derivative analyte.
13. A method of detecting at least one unknown parent analyte
comprising the steps of (a) forming an array by depositing at least
a first dye and a second dye directly onto a single support in a
predetermined pattern combination, the combination of dyes in the
array having a distinct and direct spectral absorbance or
reflectance response to distinct analytes comprising one or more
parent analytes or their derivatives, (b) partially oxidizing at
least one known parent analyte pursuant to a certain protocol to
form at least one derivative analyte corresponding to said known
parent analyte, (c) subjecting the array to the at least one
derivative analyte corresponding to said known parent analyte, (d)
inspecting the array for a direct and distinct spectral response to
the derivative analyte corresponding to said known analyte, (e)
forming an array identical to the array formed in step (a) by
repeating step (a) or returning the array in step (a) to its
condition prior to step (c), (f) partially oxidizing at least one
unknown parent analyte pursuant to the certain protocol to form at
least one derivative analyte corresponding to said unknown parent
analyte, (g) subjecting the array formed in step (e) to the at
least one derivative analyte corresponding to said unknown parent
analyte, (h) inspecting the array after step (g) for a direct and
distinct spectral response to the derivative analyte corresponding
to said unknown parent analyte, and (i) determining after step (h)
whether the direct and distinct spectral response of the array to
the derivative analyte corresponding to the unknown parent analyte
matches the direct and distinct spectral response of the array to
the derivative analyte corresponding to the known parent analyte in
step (d).
14. The method of claim 13 further comprising the step of
subjecting the array formed in step (e) to the at least one unknown
parent analyte prior to step (f) and determining whether the array
formed in step (e) has a response insufficient to detect the
unknown parent analyte prior to proceeding to step (f).
15. The method of claim 13 further comprising the step of
subjecting the array formed in step (a) to the at least one known
parent analyte prior to step (b) and determining whether the array
formed in step (a) has a response insufficient to detect the
unknown parent analyte prior to proceeding to step (b).
16. A table of responses of the array of the artificial nose of
claim 1 to a plurality of distinct analytes.
17. A method of making a table of responses of an array to a
plurality of distinct analytes comprising the steps of (a) forming
an array by depositing at least a first die and a second dye
directly onto a single support in a predetermined pattern
combination, the combination of dyes in the array having a distinct
and direct spectral absorbance or reflectance response to distinct
analytes comprising one or more parent analytes or their
derivatives, (b) subjecting the array to at least one known parent
analyte, (c) inspecting the distinct and direct absorbance or
reflectance response that exists of the array to the known parent
analyte, (d) if no distinct and direct absorbance or reflectance
response exists of the array to the at least one known parent
analyte, then partially oxidizing the at least one known parent
analyte pursuant to a certain protocol to form at least one
derivative analyte corresponding to said known parent analyte, (e)
subjecting the array to the at least one derivative analyte
corresponding to said known parent analyte, (f) inspecting the
array for a direct and distinct spectral response to the derivative
analyte corresponding to said known analyte, (g) forming an array
identical to the array formed in step (a) by repeating step (a) or
returning the array in step (a) to its condition prior to step (b),
(h) subjecting the array formed in step (g) to at least one unknown
parent analyte to determine whether the array has a response
sufficient to detect the unknown parent analyte, (i) if after step
(h) the array has a response sufficient to detect the unknown
parent analyte, then determining whether the response matches the
response of a known patent analyte in step (c), (j) if after step
(h) the array does not have a response sufficient to detect the
unknown parent analyte, then partially oxidizing the at least one
unknown parent analyte pursuant to the certain protocol to form at
least one derivative analyte corresponding to said unknown parent
analyte, (k) subjecting the array after step 0) to the at least one
derivative analyte corresponding to said unknown parent analyte,
(l) inspecting the array after step (k) for a direct and distinct
spectral response corresponding to the derivative analyte
corresponding to said unknown parent analyte, and (m) determining
after step (1) whether the direct and distinct spectral response of
the array to the derivative analyte corresponding to the unknown
parent analyte matches the direct and distinct spectral response of
the array to the derivative analyte corresponding to the known
parent analyte in step (f).
18. The method of claim 12 further comprising the step of forming a
table of responses of the array to a plurality of distinct
analytes.
19. An artificial tongue comprising an array, the array comprising
at least a first dye and a second dye deposited directly onto a
single support in a predetermined pattern combination, the
combination of dyes in the array having a distinct and direct
spectral absorbance or reflectance response to distinct analytes
comprising one or more parent analytes or their derivatives,
wherein the one or more parent analytes or their derivatives are in
solution or liquid analytes, or analytes in a solid or solid
analytes, and an oxidizing source to partially oxidize at least one
distinct parent analyte to at least one corresponding derivative
analyte of said parent analyte, the array at least in part having a
stronger distinct and direct absorbance or reflectance response to
the derivative analyte than to the corresponding parent
analyte.
20. The artificial tongue of claim 19, wherein the at least one
distinct parent analyte is from the group consisting of organic
compounds lacking ligatable functionality and molecules sterically
hindered as to preclude effective ligation, acid-base interaction
functionality, hydrogen-base interaction functionality, and dipolar
interaction functionality.
21. The artificial tongue of claim 19, wherein the at least one
corresponding derivative analyte has a stronger interaction with at
least part of the array than its corresponding parent analyte.
22. The artificial tongue of claim 21, wherein the stronger
interaction is from the group consisting of ligation interaction,
acid-base interaction, hydrogen-base interaction, and dipolar
interaction.
23. The artificial tongue of claim 19, wherein the oxidizing source
comprises an oxidation catalyst.
24. The artificial tongue of claim 23, wherein the oxidation
catalyst from the group consisting of noble metals, noble metal
oxides, early transition metals oxides and metal-containing
microporous zeolites.
25. The artificial tongue of claim 23, wherein the oxidation
catalyst is contained in a cartridge.
26. The artificial tongue of claim 19, wherein the oxidizing source
is from the group consisting of substantially pure oxygen, air,
hydrogen peroxide, hypochlorite, chlorine dioxide, chlorine or
other bleaching agents.
27. The artificial tongue of claim 23, wherein the oxidation
catalyst is from the group consisting of platinum, palladium, and
vanadium oxide.
28. The artificial tongue of claim 23, wherein the partial
oxidation of the at least one distinct analyte is conducted in a
temperature range of between 100 K and 1000 K.
29. The artificial tongue of claim 19, wherein the at least one
derivative analyte is from the group consisting of alcohols,
aldehydes, ketones, carboxylic acids, carbon monoxide, and carbon
dioxide.
30. A table of responses of the array of the artificial tongue of
claim 19 to a plurality of distinct analytes.
Description
CONTINUING APPLICATION DATA
[0001] This application is a Continuation-in-Part of U.S.
application Ser. No. 09/705,329, filed on Nov. 3, 2000, which is a
Continuation-in-Part of U.S. application Ser. No. 09/532,125, filed
on Mar. 21, 2000, now U.S. Pat. No. 6,368,558.
FIELD OF THE INVENTION
[0003] The present invention relates to methods and apparatus for
artificial olfaction, e.g., artificial noses, for the detection of
odorants by a visual display.
BACKGROUND OF THE INVENTION
[0004] There is a great need for olfactory or vapor-selective
detectors (i.e., "artificial noses") in a wide variety of
applications. For example, there is a need for artificial noses
that can detect low levels of odorants and/or where odorants may be
harmful to humans, animals or plants. Artificial noses that can
detect many different chemicals are desirable for personal
dosimeters in order to detect the type and amount of odorants
exposed to a human, the presence of chemical poisons or toxins, the
spoilage in foods, the presence of flavorings, or the presence of
vapor emitting items, such as plant materials, fruits and
vegetables, e.g., at customs portals.
[0005] Conventional artificial noses have severe limitations and
disadvantages and are not considered generally useful for such
purposes. Limitations and disadvantages of conventional artificial
noses include their need for extensive signal transduction
hardware, and their inability to selectively target
metal-coordinating vapors and toxins. In addition, artificial noses
which incorporate mass sensitive signal transduction or polar
polymers as sensor elements are susceptible to interference by
water vapor. This limitation is significant in that it can cause
variable response of the detector with changes ambient humidity.
See F. L. Dickert, O. Hayden, Zenkel, M. E. Anal. Chem. 71, 1338
(1999).
[0006] Initial work in the field of artificial noses was conducted
by Wilkens and Hatman in 1964, though the bulk of research done in
this area has been carried out since the early 1980's. See, e.g.,
W. F. Wilkens, A. D. Hatman. Ann. NY Acad. Sci., 116, 608 (1964);
K. Pursaud, G. H. Dodd. Nature, 299, 352-355 (1982); and J. W.
Gardner, P. N. Bartlett. Sensors and Actuators B, 18-19, 211-220
(1994).
[0007] Vapor-selective detectors or "artificial noses" are
typically based upon the production of an interpretable signal or
display upon exposure to a vapor emitting substance or odorant
(hereinafter sometimes referred to as an "analyte"). More
specifically, typical artificial noses are based upon selective
chemical binding or an interface between a detecting compound of
the artificial nose and an analyte or odorant, and then
transforming that chemical binding into a signal or display, i.e.,
signal transduction.
[0008] Polymer arrays having a single dye have been used for
artificial noses. That is, a series of chemically-diverse polymers
or polymer blends are chosen so that their composite response
distinguishes a given odorant or analyte from others. Examples of
polymer array vapor detectors, including conductive polymer and
conductive polymer/carbon black composites, are discussed in: M. S.
Freund, N. S. Lewis, Proc. Natl. Acad. Sci. U.S. Pat. No.
92,2652-2656 (1995); B. J. Doleman, R. D. Sanner, E. J. Severin, R.
H. Grubbs, N. S. Lewis, Anal. Chem. 70, 2560-2564 (1998); T. A.
Dickinson, J. White, J. S. Kauer, D. R. Walt, Nature 382, 697-700
(1996) (polymer array with optical detection); A. E. Hoyt, A. J.
Ricco, H. C. Yang, R. M. Crooks, J. Am. Chem. Soc. 117, 8672
(1995); and J. W. Grate, M. H. Abraham, Sensors and Actuators B 3,
85-111 (1991).
[0009] Other interface materials include functionalized
self-assembled monolayers (SAM), metal oxides, and dendrimers.
Signal transduction is commonly achieved with mass sensitive
piezoelectric substrates, surface acoustic wave (SAW) transducers,
or conductive materials. Optical transducers (based on absorbance
or luminescence) have also been examined. Examples of metal oxide,
SAM, and dendrimer-based detectors are discussed in J. W. Gardner,
H. V. Shurmer, P. Corcoran, Sensors and Actuators B 4, 117-121
(1991); J. W. Gardner, H. V. Shurmer, T. T. Tan, Sensors and
Actuators B 6, 71-75 (1992); and R. M. Crooks, A. J. Ricco, Acc.
Chem. Res. 31, 219-227 (1998). These devices also use a single
dye.
[0010] Techniques have also been developed using a metalloporphyrin
for optical detection of a specific, single gas such as oxygen or
ammonia, and for vapor detection by chemically interactive layers
on quartz crystal microbalances. See A. E. Baron, J. D. S.
Danielson, M. Gouterman, J. R. Wan, J. B. Callis, Rev. Sci.
Instrum. 64, 3394-3402 (1993); J. Kavandi, et al., Rev. Sci.
Instrum. 61, 3340-3347 (1990); W. Lee, et al., J. Mater. Chem. 3,
1031-1035 (1993); A. A. Vaughan, M. G. Baron, R. Narayanaswamy,
Anal Comm. 33, 393-396 (1996); J. A. J. Brunink, et al., Anal.
Chim. Acta 325, 53-64 (1996); C. Di Natale, et al., Sensors and
Actuators B 44, 521-526 (1997); and C. Di Natale, et al., Mat. Sci.
Eng. C 5, 209-215 (1998). However, these techniques either require
extensive signal transduction hardware, or, as noted above, are
limited to the detection of a specific, single gas. They are also
subject to water vapor interference problems, as discussed
previously.
[0011] While typical systems to date have demonstrated some success
in chemical vapor detection and differentiation, these systems have
focused on the detection of non-metal binding or non-metal ligating
solvent vapors, such as arenes, halocarbons and ketones. Detection
of metal-ligating vapors (such as amines, thiols, and phosphines)
has been much less explored. Further, while some single porphyrin
based sensors have been used for detection of a single strong acid,
there is a need for sensor devices that will detect a wide variety
of vapors.
[0012] To summarize, there are a number of limitations and
drawbacks to typical artificial noses and single porphyrin based
sensors. As noted above typical artificial noses are not designed
for metal binding and metal ligating vapors, such as amines,
thiols, and phosphines. Further, typical artificial noses require
extensive signal transduction hardware, and are subject to
interference from water vapor. As noted above, single porphyrin
based sensors have been used for detection of a single strong acid,
but cannot detect a wide variety of vapors. Thus, there is a need
for new artificial noses and methods that overcome these and other
limitations of prior artificial noses and single porphyrin based
sensors and methods.
SUMMARY OF THE INVENTION
[0013] The present invention comprises an array of dyes including
at least a first dye and a second dye which in combination provide
a spectral response distinct to an analyte or odorant. The dyes of
the present invention produce a response in the spectrum range of
about 200 nanometers to 2,000 nanometers, which includes the
visible spectrum of light. It has now been discovered that an array
of two or more dyes responds to a given ligating species with a
unique color pattern spectrally and in a time dependent manner.
Thus, dyes in the array of the present invention are capable of
changing color in a distinct manner when exposed to any one analyte
or odorant. The pattern of colors manifested by the multiple dyes
is indicative of a specific or given analyte. In other words, the
pattern of dye colors observed is indicative of a particular vapor
or liquid species.
[0014] In a preferred embodiment, the dyes of the array are
porphyrins. In another preferred embodiment, the porphyrin dyes are
metalloporphyrins. In a further preferred embodiment, the array
will comprise ten to fifteen distinct metalloporphyrins in
combination. Metalloporphyrins are preferable dyes in the present
invention because they can coordinate metal-ligating vapors through
open axial coordination sites, and they produce large spectral
shifts upon binding of or interaction with metal-ligating vapors.
In addition, porphyrins, metalloporphyrins, and many dyes show
significant color changes upon changes in the polarity of their
environment; this so-called solvatochromic effect will give net
color changes even in the absence of direct bonding between the
vapor molecules and the metal ions. Thus, metalloporphyrins produce
intense and distinctive changes in coloration upon ligand binding
with metal ligating vapors.
[0015] The present invention provides a means for the detection or
differentiation and quantitative measurement of a wide range of
ligand vapors, such as amines, alcohols, and thiols. Further, the
color data obtained using the arrays of the present innovation may
be used to give a qualitative fingerprint of an analyte, or may be
quantitatively analyzed to allow for automated pattern recognition
and/or determination of analyte concentration. Because porphyrins
also exhibit wavelength and intensity changes in their absorption
bands with varying solvent polarity, weakly ligating vapors (e.g.,
arenes, halocarbons, or ketones) are also differentiable.
[0016] Diversity within the metalloporphyrin array may be obtained
by variation of the parent porphyrin, the porphyrin metal center,
or the peripheral porphyrin substituents. The parent porphyrin is
also referred to as a free base ("FB") porphyrin, which has two
central nitrogen atoms protonated (i.e., hydrogen cations bonded to
two of the central pyrrole nitrogen atoms). A preferred parent
porphyrin is depicted in FIG. 2A, with the substitution of a two
hydrogen ion for the metal ion (depicted as "M") in the center of
the porphyrin. In FIG. 2A, TTP stands for 5,10,1
5,20-tetraphenylporphyrinate(-2).
[0017] In accordance with the present invention, colorimetric
difference maps can be generated by subtracting unexposed and
exposed metalloporphyrin array images (obtained, for example, with
a common flatbed scanner or inexpensive video or charge coupled
device ("CCD") detector) with image analysis software. This
eliminates the need for extensive and expensive signal transduction
hardware associated with previous techniques (e.g., piezoelectric
or semiconductor sensors). By simply differencing images of the
array before and after exposure to analytes, the present invention
provides unique color change signatures for the analytes, for both
qualitative recognition and quantitative analysis.
[0018] Sensor plates which incorporate vapor sensitive combinations
of dyes comprise an embodiment of the present invention which is
economical, disposable, and can be utilized to provide qualitative
and/or quantitative identification of an analyte. In accordance
with the present invention, a catalog of arrays and the resultant
visual pattern for each analyte can be coded and placed in a
look-up table or book for future reference. Thus, the present
invention includes a method of detecting an analyte comprising the
steps of forming an array of at least a first dye and a second dye,
subjecting the array to an analyte, inspecting the first and second
dyes for a spectral response, and comparing the spectral response
with a catalog of analyte spectral responses to identify the
analyte.
[0019] Because sensing is based upon either covalent interaction
(i.e., ligation) or non-covalent solvation interactions between the
analyte and the porphyrin array, a broad spectrum of chemical
species is differentiable. While long response times (e.g., about
45 minutes) are observed at low analyte concentrations of about 1
ppm with reverse phase silica gel plates, use of impermeable solid
supports (such as polymer- or glass-based micro-array plates)
substantially increases the low-level response to less than 5
minutes.
[0020] Thus, it is an object of the present invention to provide
methods and devices for artificial olfaction, vapor-selective
detectors or artificial noses for a wide variety of applications.
It is another object of the present invention to provide methods of
detection and artificial noses that can detect low levels of
odorants and/or where odorants may be harmful to living human,
animal or plant cells. It is also an object of the present
invention to provide methods of olfactory detection and artificial
noses that can detect and quantify many different chemicals for
dosimeters that can detect chemical poisons or toxins, that can
detect spoilage in foods, that can detect flavorings and additives,
and that can detect plant materials, e.g., fruits and
vegetables.
[0021] Another object of the present invention is to provide for
the detection of analytes using data analysis/pattern recognition
techniques, including automated techniques.
[0022] Another object of the invention is to provide an artificial
nose comprising an array, the array comprising at least a first dye
and a second dye deposited directly onto a single support in a
predetermined pattern combination, the combination of the dyes in
the array having a distinct and direct spectral absorbance or
reflectance response to an analyte wherein the first dye and the
second are selected from the group of dyes consisting of
chemoresponsive dyes, and the second dye is distinct from the first
dye. In one embodiment, the first dye is selected from the group
consisting of porphyrin, chlorin, chlorophyll, phtahlocyanine, and
salen and their metal complexes. In another embodiment, the second
dye is selected from the group consisting of acid-base indicator
dyes and solvatochromic dyes.
[0023] Another object of the invention is to provide a method of
detecting an analyte comprising the steps of: (a) forming an array
of at least a first dye and a second dye deposited directly onto a
single support in a predetermined pattern combination, the
combination of the dyes in the array having a distinct and direct
spectral absorbance or reflectance response to an analyte wherein
the first dye and the second dye are selected from the group
consisting of chemoresponsive dyes, and the second dye is distinct
from the first dye, (b) subjecting the array to an analyte, (c)
inspecting the array for a distinct and direct spectral absorbance
or reflectance response, and (d) correlating the distinct and
direct spectral response to the presence of the analyte. In one
embodiment, the first dye is selected from the group consisting of
porphyrin, chlorin, chlorophyll, phtahlocyanine, and salen and
their metal complexes. In another embodiment, the second dye is
selected from the group consisting of acid-base indicator dyes and
solvatochromic dyes.
[0024] Another object of the invention is to provide an artificial
tongue comprising an array, the array comprising at least a first
dye and a second dye deposited directly onto a single support in a
predetermined pattern combination, the combination of the dyes in
the array having a distinct and direct spectral absorbance or
reflectance response to an analyte wherein the first dye and the
second are selected from the group of dyes consisting of
chemoresponsive dyes, and the second dye is distinct from the first
dye. In one embodiment, the first dye is selected from the group
consisting of porphyrin, chlorin, chlorophyll, phtahlocyanine, and
salen and their metal complexes. In another embodiment, the second
dye is selected from the group consisting of acid-base indicator
dyes and solvatochromic dyes.
[0025] Another object of the invention is to provide an artificial
nose comprising an array, the array comprising at least a first dye
and a second dye deposited directly onto a single support in a
predetermined pattern combination, the combination of dyes in the
array having a distinct and direct spectral absorbance or
reflectance response to distinct analytes comprising one or more
parent analytes or their derivatives, and an oxidizing source to
partially oxidize at lest one distinct parent analyte to at least
one corresponding derivative analyte of said parent analyte, the
array at least in part having a stronger distinct and direct
absorbance or reflectance response to the derivative analyte than
to the corresponding parent analyte
BRIEF DESCRIPTION OF THE DRAWINGS
[0026] The file of this patent contains at least one drawing
executed in color. Copies of this patent with color drawing(s) will
be provided by the Patent and Trademark Office upon request and
payment of the necessary fee.
[0027] FIG. 1 illustrates an embodiment of the optical sensing
plate of the present invention using a first elution in the y axis
and a second elution in the x axis of the plate. In this embodiment
the first elution R-OH/hexane and the second elution is
R-SH/hexane.
[0028] FIG. 2A illustrates an embodiment of the invention using
metalloporphyrins as the sensing dyes.
[0029] FIG. 2B illustrates an embodiment of the invention using
metalloporphyrins as the sensing dyes.
[0030] FIG. 3A illustrates a vapor exposure apparatus for
demonstration of the present invention.
[0031] FIG. 3B illustrates a vapor exposure apparatus for
demonstration of the present invention.
[0032] FIG. 4 illustrates the color change profile in a
metalloporphyrin array of FIG. 2 when used in the vapor exposure
apparatus of FIG. 3A to detect n-butylamine. Metalloporphyrins were
immobilized on reverse phase silica gel plates.
[0033] FIG. 5 illustrates a comparison of color changes at
saturation for a wide range of analytes. Each analyte was delivered
to the array as a nitrogen stream saturated with the analyte vapor
at 20.degree. C. DMF stands for dimethylformamide; THF stands for
tetrahydrofuran.
[0034] FIG. 6 illustrates two component saturation responses of
mixtures of 2-methylpyridine and trimethylphosphite. Vapor mixtures
were obtained by mixing two analyte-saturated N.sub.2 streams at
variable flow ratios.
[0035] FIG. 7 illustrates a comparison of Zn(TPP) spectral shifts
upon exposure to ethanol and pyridine (py) in methylene chloride
solution (A) and on the reverse phase support (B).
[0036] FIG. 8 illustrates another embodiment of the present
invention, and more particularly, an small array comprising
microwells built into a wearable detector which also contains a
portable light source and a light detector, such as a
charge-coupled device (CCD) or photodiode array.
[0037] FIG. 9 illustrates another embodiment of the present
invention, and more particularly, a microwell porphyrin array
wellplate constructed from polydimethylsiloxane (PDMS).
[0038] FIG. 10 illustrates another embodiment of the present
invention, and more particularly, a microplate containing machined
teflon posts, upon which the porphyrin array is immobilized in a
polymer matrix (polystyrene/dibutylphthalate).
[0039] FIG. 11 illustrates another embodiment of the present
invention, showing a microplate of the type shown in FIG. 10,
consisting of a minimized array of four metalloporphyrins, showing
the color profile changes for n-octylamine, dodecanethiol, and
tri-n-butylphosphine, each at 1.8 ppm.
[0040] FIG. 12 illustrates the immunity of the present invention to
interference from water vapor.
[0041] FIG. 13 illustrates the synthesis of siloxyl-substituted
bis-pocket porphyrins in accordance with the present invention.
[0042] FIGS. 14a, 14b, and 14c illustrate differences in K.sub.eq
for various porphyrins.
[0043] FIG. 15 illustrates molecular models of Zn(Si.sub.6PP) (left
column) and Zn(Si.sub.8PP) (right column).
[0044] FIG. 16 illustrates an array containing illustrative
examples of porphyrin, metalloporphyrin, acid-base indicator, and
solvatochromatic dyes.
[0045] FIG. 17 illustrates the response of the array described in
FIG. 16 to acid vapors, specifically formic acid, acetic acid,
iso-valeric acid, and 3-methyl-2-hexenoic acid.
[0046] FIG. 18 illustrates a preferred array containing
illustrative examples of porphyrin, metalloporphyrin, acid-base
indicator, and solvatochromatic dyes.
[0047] FIG. 19 illustrates the response of the array described in
FIG. 18 to acetone.
[0048] FIG. 20 illustrates a vapor exposure apparatus shown in FIG.
3B, further having a partial oxidation cartridge to provide
increased sensitivity to analytes.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0049] Production of the Sensor Plate of the Present Invention
[0050] A sensor plate 10 fabricated in accordance with the present
invention is shown in FIG. 1. Sensor plate 10 comprises a
two-dimensionally spatially resolved array 12 of various sensing
elements or dyes 14 capable of changing color upon interaction
(e.g., binding, pi-pi complexation, or polarity induced shifts in
color). As shown in FIG. 1, a library of such dyes 14 can be given
spatial resolution by two-dimensional chromatography or by direct
deposition, including, but not limited to, ink-jet printing,
micropipette spotting, screen printing, or stamping. In FIG. 1,
metalloporphyrin mixture 6 is placed at origin 7. Next, the
metalloporphyrin mixture 6 is eluted through a silica gel or
reversed-phase silica gel 5 in sensor plate 10, and the
metalloporphyrins are spatially resolved from each other and
immobilized in silica gel 5 as depicted by the oval and circular
shapes 4 as shown in FIG. 1. Sensor plate 10 can be made from any
suitable material or materials, including but not limited to,
chromatography plates, paper, filter papers, porous membranes, or
properly machined polymers, glasses, or metals.
[0051] FIG. 1 also illustrates an embodiment of the optical sensing
plate of the present invention using a first elution 8 in the y
axis and a second elution 9 in the x axis of sensor plate 10. In
this embodiment, the first elution 8 is R--OH/hexane and the second
elution 9 is R--SH/hexane. The order of the first and second
elutions can be reversed. The first and second elutions are used to
spatially resolve the metalloporphyrin mixture 6 in silica gel 5.
As shown in FIG. 1, the upper left hand quadrant 3 is characterized
by metalloporphyrins that are "hard" selective, i.e., having a
metal center having a high chemical hardness, i.e., a high charge
density. As shown in FIG. 1, the lower right hand quadrant 2 is
characterized by metalloporphyrins that are "soft" selective, i.e.,
having a metal center having a low chemical hardness, i.e., a low
charge density. In accordance with the present invention, the array
can be a spatially resolved collection of dyes, and more
particularly a spatially resolved combinatorial family of dyes.
[0052] In accordance with the present invention, a
porphyrin-metalloporphy- rin sensor plate was prepared and then
used to detect various odorants. More specifically, solutions of
various metalated tetraphenylporphyrins in either methylene
chloride or chlorobenzene were spotted in 1 .mu.L aliquots onto two
carbon ("C2", i.e, ethyl-capped) reverse phase silica thin layer
chromatography plates (Product No. 4809-800, by Whatman, Inc.,
Clifton, N.J.) to yield the sensor array 16 seen in FIG. 2B. As
shown in FIG. 2B and summarized in Table 1 below, the dyes have the
following colors (the exact colors depend, among other things, upon
scanner settings).
1TABLE 1 (Summarizing Colors of Dyes in FIG. 2B) Sn.sup.4+ - Green
Co.sup.3+ - Red Cr.sup.3+ - Deep Green Mn.sup.3+ - Green Fe.sup.3+
- Dark Red Co.sup.2+ - Red Cu.sup.2+ - Red Ru.sup.2+ - Light Yellow
Zn.sup.2+ - Greenish Red Ag.sup.2+ - Red 2H.sup.+ (Free Base "FB")
-- Red
[0053] A metalloporphyrin 15, sometimes referred to as M(TPP), of
the present invention is depicted in FIG. 2A. FIG. 2A also depicts
various metals of the metalloporphyrins 15 of the present
invention, and corresponding metal ion charge to radius ratio
(i.e., Z/r Ratio) in reciprocal angstroms. The Z/r Ratio should
preferably span a wide range in order to target a wide range of
metal ligating analytes. These metalloporphyrins have excellent
chemical stability on the solid support and most have well-studied
solution ligation chemistry. Reverse phase silica was chosen as a
non-interacting dispersion medium for the metalloporphyrin array 16
depicted in FIG. 2B, as well as a suitable surface for diffuse
reflectance spectral measurements. More importantly, the reverse
phase silica presents a hydrophobic interface, which virtually
eliminates interference from ambient water vapor. After spotting,
sensor plates 18 like the one depicted in FIG. 2B were dried under
vacuum at 50.degree. C. for 1 hour prior to use. Thus,
immobilization of the metalloporphyrins on a reverse phase silica
support is obtained. While ten (10) different metalloporphyrins are
shown in FIG. 2A, those of skill in the art will recognize that
many other metalloporphyrins are useful in accordance with the
present invention. Those of skill in the art will further recognize
that in accordance with the broad teachings of the present
invention, any dyes capable of changing color upon interacting with
an analyte, both containing and not containing metal ions, are
useful in the array of the present invention.
[0054] Colorimetric Analysis Using the Sensor Plate
[0055] For the detection and analysis of odorants in accordance
with the present invention, one needs to monitor the absorbance of
the sensor plate at one or more wavelengths in a spatially resolved
fashion. This can be accomplished with an imaging
spectrophotometer, a simple flatbed scanner (e.g. a Hewlett Packard
Scanjet 3c), or an inexpensive video or CCD camera.
[0056] FIG. 3A illustrates a vapor exposure apparatus 19 of the
present invention. FIG. 3B illustrates top and side views of bottom
piece 21 and a top view of top piece 21' of a vapor exposure flow
cell 20 of the present invention. In an embodiment of the present
invention for purposes of demonstration, each sensor plate 18 was
placed inside of a stainless steel flow cell 20 equipped with a
quartz window 22 as shown in FIGS. 3A and 3B. Scanning of the
sensor plate 18 was done on a commercially available flatbed
scanner 24 (Hewlett Packard Scanjet 3c) at 200 dpi resolution, in
full color mode. Following an initial scan, a control run with a
first pure nitrogen flow stream 26 was performed. The array 16 of
plate 18 was then exposed to a second nitrogen flow stream 28
saturated with a liquid analyte 30 of interest. As shown in FIG.
3A, the nitrogen flow stream 28 saturated with liquid analyte 30
results in a saturated vapor 32. Saturated vapor 32, containing the
analyte 30 of interest were generated by flowing nitrogen flow
stream 28 at 0.47 L/min. through the neat liquid analyte 30 in a
water-jacketed, glass fritted bubbler 34. Vapor pressures were
controlled by regulating the bubbler 34 temperature. As shown in
FIG. 3B, vapor channels 23 permit vapor flow to sensor plate
18.
EXAMPLE 1
[0057] Scanning at different time intervals and subtracting the
red, green and blue ("RGB") values of the new images from those of
the original scan yields a color change profile. This is shown for
n-butylamine in FIG. 4, in which color change profiles of the
metalloporphyrin sensor array 16 as a function of exposure time to
n-butylamine vapor. Subtraction of the initial scan from a scan
after 5 min. of N.sub.2 exposure was used as a control, giving a
black response, as shown. 9.3% n-butylamine in N.sub.2 was then
passed over the array and scans made after exposure for 30 s, 5
min., and 15 min. The red, green and blue ("RGB") mode images were
subtracted (absolute value) to produce the color change profiles
illustrated. Virtually all porphyrins are saturated after 30
seconds of exposure, yielding a color fingerprint unique for each
class of analytes, which is illustrated in FIG. 4.
[0058] More specifically, subtraction of the initial scan 40 from a
scan after 5 min. of N.sub.2 exposure was used as a control, giving
a black response, as shown in FIG. 4. A nitrogen flow stream
containing 0.093% n-butylamine was then passed over the array 16
and scans 42, 44, and 46 were made after exposure for 30 seconds, 5
minutes, and 15 minutes, respectively. The RGB mode images were
subtracted (absolute value) using Adobe Photoshop.TM. (which
comprises standard image analyzing software), with contrast
enhancement by expanding the pixel range (a 32 value range was
expanded to 256 each for the R, G, and B values). Subtraction of
exposed and unexposed images gives color change patterns that vary
in hue and intensity. Because differentiation is provided by an
array of detectors, the system has parallels the mammalian
olfactory system. As shown in FIG. 4 and summarized in Table 2
below, the dyes have the following colors in scans 42, 44, and
46.
2TABLE 2 (Summarizing Colors of Dyes in FIG. 4, Scans 42, 44, and
46) Sn.sup.4+ - No Change Co.sup.3+ - Green Cr.sup.3+ - Green
Mn.sup.3+ - No Change Fe.sup.3+ - Red Co.sup.2+ - Faint Green
Cu.sup.2+ - No Change Ru.sup.2+ - No Change Zn.sup.2+ - Light Green
Ag.sup.2+ - No Change 2H.sup.+ (Free Base "FB") -- Light Blue
[0059] As summarized in Table 3 below, for the TTP array 16
depicted on the left-hand side of FIG. 4, the dyes have the
following colors.
3TABLE 3 Sn.sup.4+ - Greenish Yellow Co.sup.3+ - Red Cr.sup.3+ -
Yellow with Dark Red Center Mn.sup.3+ - Greenish Yellow Fe.sup.3+ -
Dark Red Co.sup.2+ - Red Cu.sup.2+ - Red Ru.sup.2+ - Light Yellow
Zn.sup.2+ - Red Ag.sup.2+ - Red 2H.sup.+ (Free Base "FB") --
Red
EXAMPLE 2
[0060] Visible spectral shifts and absorption intensity differences
occur upon ligation of the metal center, leading to readily
observable color changes. As is well known to those with skill in
the art, the magnitude of spectral shift correlates with the
polarizability of the ligand; hence, there exists an electronic
basis for analyte distinction. Using metal centers that span a
range of chemical hardness and ligand binding affinity, a wide
range of volatile analytes (including soft ligands, such as thiols,
and harder ligands, such as amines) are differentiable. Because
porphyrins have been shown to exhibit wavelength and intensity
changes in their absorption bands with varying solvent polarity, it
is contemplated that the methods and apparatus of the present
invention can be used to calorimetrically distinguish among a
series of weakly ligating solvent vapors (e.g., arenes,
halocarbons, or ketones), as shown for example in FIG. 5.
[0061] A comparison of color changes at saturation for a wide range
of analytes is shown in FIG. 5. Each analyte is identified under
the colored array 16 that identifies each analyte. ). DMF stands
for the analyte dimethylformamide, and THF stands for the analyte
tetrahydrofuran. As shown in FIG. 5 and summarized in Table 4
below, the colors of each dye in response to a particular analyte
are as follows.
4TABLE 4 Analyte: DMF Sn.sup.4+ - No Change Co.sup.3+ - Green
Cr.sup.3+ - No Change Mn.sup.3+ - No Change Fe.sup.3+ - No Change
Co.sup.2+ - No Change Cu.sup.2+ - Blue Ru.sup.2+ - No Change
Zn.sup.2+ - No Change Ag.sup.2+ - No Change 2H.sup.+ (Free Base
"FB") -- Blue Analyte: Ethanol Sn.sup.4+ - Dark Blue Co.sup.3+ - No
Change Cr.sup.3+ - Red Mn.sup.3+ - No Change Fe.sup.3+ - No Change
Co.sup.2+ - No Change Cu.sup.2+ - No Change Ru.sup.2+ - No Change
Zn.sup.2+ - Blue Ag.sup.2+ - No Change 2H.sup.+ (Free Base "FB") -
No Change Analyte: Pyridine Sn.sup.4+ - No Change Co.sup.3+ - Green
Cr.sup.3+ - Dark Green Mn.sup.3+ - No Change Fe.sup.3+ - No Change
Co.sup.2+ - No Change Cu.sup.2+ - No Change Ru.sup.2+ - No Change
Zn.sup.2+ - Green Ag.sup.2+ - No Change 2H.sup.+ (Free Base "FB")
-- Blue Analyte: Hexylamine Sn.sup.4+ - No Change Co.sup.3+ - Dark
Green Cr.sup.3+ - Green Mn.sup.3+ - No Change Fe.sup.3+ - Red
Co.sup.2+ - No Change Cu.sup.2+ - Blue Ru.sup.2+ - No Change
Zn.sup.2+ - Green Ag.sup.2+ - Dark Blue 2H.sup.+ (Free Base "FB")
-- Blue Analyte: Acetonitrile Sn.sup.4+ - Blue Co.sup.3+ - Dark
Green Cr.sup.3+ - No Change Mn.sup.3+ - Yellow Fe.sup.3+ - Dark
Green Co.sup.2+ - No Change Cu.sup.2+ - Blue Ru.sup.2+ - Blue
(faint dot) Zn.sup.2+ - Blue Ag.sup.2+ - No Change 2H.sup.+ (Free
Base "FB") -- Blue Analyte: Acetone Sn.sup.4+ - No Change Co.sup.3+
- No Change Cr.sup.3+ - Red (small dot) Mn.sup.3+ - No Change
Fe.sup.3+ - No Change Co.sup.2+ - No Change Cu.sup.2+ - Dark Blue
Ru.sup.2+ - No Change Zn.sup.2+ - Dark Blue Ag.sup.2+ - No Change
2H.sup.+ (Free Base "FB") -- Blue Analyte: THF Sn.sup.4+ - Dark
Blue Co.sup.3+ - Green Cr.sup.3+ - Red Mn.sup.3+ - Blue (small dot)
Fe.sup.3+ - Dark Green Co.sup.2+ - No Change Cu.sup.2+ - Blue
Ru.sup.2+ - No Change Zn.sup.2+ - Blue Ag.sup.2+ - No Change
2H.sup.+ (Free Base "FB") -- Blue Analyte: CH.sub.2Cl.sub.2
Sn.sup.4+ - Dark Blue Co.sup.3+ - No Change Cr.sup.3+ - No Change
Mn.sup.3+ - Yellow and Red (small Fe.sup.3+ - No Change Co.sup.2+ -
No Change dot) Cu.sup.2+ - Dark Blue Ru.sup.2+ - No Change
Zn.sup.2+ - No Change Ag.sup.2+ - No Change 2H.sup.+ (Free Base
"FB") -- Blue Analyte: CHCl.sub.3 Sn.sup.4+ - Dark Blue Co.sup.3+ -
Dark Green Cr.sup.3+ - Yellow (circle) Mn.sup.3+ - Yellow Fe.sup.3+
- Dark Green (very faint) Co.sup.2+ - No Change Cu.sup.2+ - Dark
Blue (very faint) Ru.sup.2+ - No Change Zn.sup.2+ - Blue Ag.sup.2+
- Blue (very faint) 2H.sup.+ (Free Base "FB") -- Blue Analyte:
P(OC.sub.2H.sub.5).sub.3 Sn.sup.4+ - No Change Co.sup.3+ - Yellow
Cr.sup.3+ - Dark Green Mn.sup.3+ - No Change Fe.sup.3+ - Dark Green
(very faint) Co.sup.2+ - Greenish Yellow Cu.sup.2+ - Dark Blue
(faint) Ru.sup.2+ - No Change Zn.sup.2+ - Greenish Blue Ag.sup.2+ -
Blue (very faint) 2H.sup.+ (Free Base "FB") -- Blue Analyte:
P(C.sub.4H.sub.9).sub.3 Sn.sup.4+ - No Change Co.sup.3+ - Yellow
and Red Cr.sup.3+ - Deep Red Mn.sup.3+ - No Change Fe.sup.3+ - Dark
Green (faint) Co.sup.2+ - Red (with some yellow) Cu.sup.2+ - No
Change Ru.sup.2+ - Dark Blue Zn.sup.2+ - Yellow Ag.sup.2+ - No
Change 2H.sup.+ (Free Base "FB") -- No Change Analyte:
C.sub.6H.sub.13SH Sn.sup.4+ - Green Co.sup.3+ - No Change Cr.sup.3+
- Yellow circle surrounded by greenish blue circle Mn.sup.3+ -
Yellow Fe.sup.3+ - Dark Green Co.sup.2+ - No Change Cu.sup.2+ -
Dark Blue (faint) Ru.sup.2+ - No Change Zn.sup.2+ - Green Ag.sup.2+
- Blue (very faint) 2H.sup.+ (Free Base "FB") -- Blue Analyte:
(C.sub.3H.sub.7).sub.2S Sn.sup.4+ - Dark Blue (faint) Co.sup.3+ -
Deep Green Cr.sup.3+ - Green Mn.sup.3+ - No Change Fe.sup.3+ - Dark
Green Co.sup.2+ - Dark Green (very faint) Cu.sup.2+ - Dark Blue
(faint) Ru.sup.2+ - Green Zn.sup.2+ - Green Ag.sup.2+ - Blue (very
faint) 2H.sup.+ (Free Base "FB") -- Blue Analyte: Benzene Sn.sup.4+
- No Change Co.sup.3+ - Green Cr.sup.3+ - Yellow (very faint)
Mn.sup.3+ - Yellow (some green) Fe.sup.3+ - Dark Green Co.sup.2+ -
No Change Cu.sup.2+ - No Change Ru.sup.2+ - No Change Zn.sup.2+ -
Dark Green Ag.sup.2+ - No Change 2H.sup.+ (Free Base "FB") --
Blue
[0062] The degree of ligand softness (roughly their polarizability)
increases from left to right, top to bottom as shown in FIG. 1.
Each analyte is easily distinguished from the others, and there are
family resemblances among chemically similar species (e.g.,
pyridine and n-hexylamine). Analyte distinction originates both in
the metal-specific ligation affinities and in their specific,
unique color changes upon ligation. Each analyte was delivered to
the array as a nitrogen stream saturated with the analyte vapor at
20.degree. C. (to ensure complete saturation, 30 min. exposures to
vapor were used. Although these fingerprints were obtained by
exposure to saturated vapors (thousands of ppm), unique patterns
can be identified at much lower concentrations.
[0063] The metalloporphyrin array 16 has been used to quantify
single analytes and to identify vapor mixtures. Because the images'
color channel data (i.e., RGB values) vary linearly with porphyrin
concentration, we were able to quantify single porphyrin responses
to different analytes. Color channel data were collected for
individual spots and plotted, for example, as the quantity
(R.sub.plt-R.sub.spt)/(R.- sub.plt), where R.sub.plt was the red
channel value for the initial silica surface and R.sub.spt the
average value for the spot. For example, Fe(TFPP)(Cl) responded
linearly to octylamine between 0 and 1.5 ppm. Other porphyrins
showed linear response ranges that varied with ligand affinity
(i.e., equilibrium constant).
EXAMPLE 3
[0064] The array of the present invention has demonstrated
interpretable and reversible responses even to analyte mixtures of
strong ligands, such as pyridines and phosphites, as is shown in
FIG. 6. Color change patterns for the mixtures are distinct from
either of the neat vapors. Good reversibility was demonstrated for
this analyte pair as the vapor mixtures were cycled between the
neat analyte extremes, as shown in FIG. 6, which shows the two
component saturation responses to mixtures of 2-methylpyridine
("2MEPY") and trimethylphosphite ("TMP"). Vapor mixtures were
obtained by mixing the analyte-saturated N.sub.2 streams at
variable flow ratios. A single plate was first exposed to pure
trimethylphosphite vapor in N.sub.2 (Scan A), followed by
increasing mole fractions of 2-methylpyridine up to pure
2-methylpyridine vapor (Scan C), followed by decreasing mole
fractions of 2-methylpyridine back to pure trimethylphosphite
vapor. In both directions, scans were taken at the same mole
fraction trimethylphosphite and showed excellent reversibility;
scans at mole fractions at 67% trimethylphosphite
(.chi..sub.tmp=0.67, Scans B and D) and of their difference map are
shown (Scan E). Response curves for the individual porphyrins allow
for quantification of the mixture composition. The colors of each
dye upon exposure to the analytes TMP and 2MEPY are shown in FIG. 6
and are summarized in Table 5 below.
5TABLE 5 Scan A, Analyte: Neat TMP Sn.sup.4+ - Dark Blue Co.sup.3+
- Yellow Cr.sup.3+ - No Change Mn.sup.3+ - Yellow with red center
Fe.sup.3+ - Dark Green Co.sup.2+ - Greenish Yellow Cu.sup.2+ - Dark
Blue Ru.sup.2+ - No Change Zn.sup.2+ - Blue Ag.sup.2+ - Green (very
faint) 2H.sup.+ (Free Base "FB") -- Reddish Blue Scan B, Analyte:
TMP,x.sub.TMP = 0.67 Sn.sup.4+ - Blue Co.sup.3+ - Green Cr.sup.3+ -
Green (small dot) Mn.sup.3+ - Yellow and Green Fe.sup.3+ - Green
and Yellow Co.sup.2+ - Green with red center Cu.sup.2+ - Dark Blue
Ru.sup.2+ - Purple (very faint) Zn.sup.2+ - Blue Ag.sup.2+ -
Greenish Blue 2H.sup.+ (Free Base "FB") -- Reddish Blue Scan C,
Analyte: Neat 2MEPY Sn.sup.4+ - Blue Co.sup.3+ - Green Cr.sup.3+ -
No Change Mn.sup.3+ - Yellow and Green with Fe.sup.3+ - Red with
some Yellow Co.sup.2+ - Green Red center Cu.sup.2+ - Dark Blue
Ru.sup.2+ - Deep Blue Zn.sup.2+ - Green with some Blue Ag.sup.2+ -
Green with some Blue 2H.sup.+ (Free Base "FB") -- Reddish Blue Scan
D, Analyte: TMP,x.sub.TMP = 0.67 Sn.sup.4+ - Blue Co.sup.3+ - Green
Cr.sup.3+ - No Change Mn.sup.3+ - Yellow and Green Fe.sup.3+ -
Green and Yellow Co.sup.2+ - Green Cu.sup.2+ - Dark Blue Ru.sup.2+
- Purple (very faint) Zn.sup.2+ - Blue Ag.sup.2+ - Greenish Blue
(very 2H.sup.+ (Free Base "FB") -- faint) Reddish Blue Scan E
Sn.sup.4+ - No Change Co.sup.3+ - No Change Cr.sup.3+ - No Change
Mn.sup.3+ - No Change Fe.sup.3+ - No Change Co.sup.2+ - No Change
Cu.sup.2+ - Blue (very faint) Ru.sup.2+ - Blue (small dot)
Zn.sup.2+ - No Change Ag.sup.2+ - Blue (very faint) 2H.sup.+ (Free
Base "FB") -- Green
EXAMPLE 4
[0065] In an effort to understand the origin of the color changes
upon vapor exposure, diffuse reflectance spectra were obtained for
single porphyrin spots before and after exposure to analyte vapors.
Porphyrin solutions were spotted in 50 L aliquots onto a plate and
allowed to dry under vacuum at 50.degree. C. Diffuse reflectance
spectra of the plate were then taken using a UV-visible
spectrophotometer equipped with an integrating sphere. Unique
spectral shifts were observed upon analyte exposure, which
correlated well with those seen from solution ligation. For
example, Zn(TPP) exposure to ethanol and pyridine gave unique
shifts which were very similar to those resulting from ligand
exposure in solution. FIG. 7 shows a comparison of Zn(TPP) spectral
shifts upon exposure to ethanol and pyridine (py) in methylene
chloride solution (A) and on the reverse phase support (B). In both
A and B, the bands correspond, from left to right, to Zn(TPP),
Zn(TPP)(C.sub.2H.sub.5OH), and Zn(TPP)(py), respectively. Solution
spectra (A) were collected using a Hitachi U-3300
spectrophotometer; Zn(TPP), C.sub.2H.sub.5OH, and py concentrations
were approximately 2 .mu.M, 170 mM, and 200 .mu.M, respectively.
Diffuse reflectance spectra (B) were obtained with an integrating
sphere attachment before exposure to analytes, after exposure to
ethanol vapor in N.sub.2, and after exposure to pyridine vapor in
N.sub.2 for 30 min. each using the flow cell.
[0066] Improvement to Low Concentration Response
[0067] Color changes at levels as low as 460 ppb have been observed
for octylamine vapor, albeit with slow response times due to the
high surface area of the silica on the plate 18. The surface area
of C2 plates is .apprxeq.350 m.sup.2/gram. Removal of excess silica
gel surrounding the porphyrin spots from the plate 18 led to
substantial improvements in response time for exposures to trace
levels of octylamine. Because the high surface area of the reverse
phase silica surface is primarily responsible for the increased
response time, other means of solid support or film formation can
be used to improve low concentration response.
[0068] Further, the present invention contemplates miniaturization
of the array using small wells 60 (<1 mm), for example in glass,
quartz, or polymers, to hold metalloporphyrin or other dyes as thin
films, which are deposited as a solution, by liquid droplet
dispersion (e.g., airbrush or inkjet), or deposited as a solution
of polymer with metalloporphyrin.
[0069] These embodiments are depicted in FIGS. 8, 9, and 10. FIG. 8
illustrates the interfacing of a microplate 60 into an assembly
consisting of a CCD 70, a microplate 72 and a light source 74. FIG.
9 illustrates another embodiment of the present invention, and more
particularly, a microwell porphyrin array weliplate 80 constructed
from polydimethylsiloxane (PDMS). The colors of the dyes shown in
FIG. 9 are summarized below in Table 6.
6TABLE 6 Sn.sup.4+ - Dark Red Co.sup.3+ - Dark Red Cr.sup.3+ - Dark
Green Mn.sup.3+ - Green Fe.sup.3+ - Dark Red Co.sup.2+ - Yellowish
Green Cu.sup.2+ - Deep Red Ru.sup.2+ - Dark Red Zn.sup.2+ - Red
with some Yellow Ag.sup.2+ - Red 2H.sup.+ (Free Base "FB") --
Red
[0070] FIG. 10 demonstrates deposition of metalloporphyrin/polymer
(polystyrene/dibutylphthalate) solutions upon a plate, which
includes a series of micro-machined Teflon.RTM. posts 100 having
the same basic position relative to each other as shown in FIG. 2A
and FIG. 2B. The colors for the dyes in the middle of FIG. 10 are
summarized in Table 7 below.
7TABLE 7 Sn.sup.4+ - Yellow Co.sup.3+ - Orange Cr.sup.3+ - Yellow
Mn.sup.3+ - Yellow Fe.sup.3+ - Orange Co.sup.2+ - Orange Cu.sup.2+
- Orange Ru.sup.2+ - Dark Yellow Zn.sup.2+ - Orange Ag.sup.2+ -
Orange 2H.sup.+ (Free Base "FB") -- Red
[0071] The colors for the dyes on the right hand side of FIG. 10
are summarized in Table 8 below.
8TABLE 8 Sn.sup.4+ - No Change Co.sup.3+ - Green Cr.sup.3+ - Red
Mn.sup.3+ - Blue Fe.sup.3+ - Red Co.sup.2+ - Red, Green, Blue, and
Yellow Cu.sup.2+ - Green with some Blue Ru.sup.2+ - Blue (very
faint) Zn.sup.2+ - Yellow with some Red Ag.sup.2+ - Green with some
Blue 2H.sup.+ (Free Base "FB") -- Green with some Blue
EXAMPLE 5
[0072] FIG. 11 shows the color profile changes from a microplate of
the type shown in FIG. 10. The microplate, consisting of a
minimized array of four metalloporphyrins, i.e., Sn(TPP)(CL.sub.2),
Co(TPP)(Cl), Zn(TPP), Fe(TFPP)(Cl), clockwise from the upper left
(where TFPP stands for
5,10,15,20-tetrakis(pentafluorophenyl)porphyrinate). The color
profile changes are shown in FIG. 11 after exposure to low levels
of n-octylamine, dodecanethiol (C.sub.12H.sub.25 SH), and
tri-n-butylphosphine (P(C.sub.4H.sub.9).sub.3), each at 1.8 ppm,
which is summarized in Table 9 below.
9TABLE 9 Dyes on Teflon .RTM. Sn -- Dark Yellow Co -- Red Zn -- Red
Fe -- Orange with Red outline Dyes exposed to n-octylamine Sn -- No
Change Co -- Green (very faint) Zn -- Red Fe -- Green Dyes exposed
to C.sub.12H.sub.25SH Sn -- Red Co -- Green with some red, yellow
and blue (faint) Zn -- Red with some green and yellow Fe -- Blue
(very faint) Dyes exposed to P(C.sub.4H.sub.9).sub.3 Sn -- No
Change Co -- Yellow with red center and some red periphery Zn --
Green Fe -- Yellow with some Green and Blue
[0073] The low ppm levels of octylamine, an analyte of interest,
were generated from temperature-regulated octylamine/dodecane
solutions with the assumption of solution ideality. The dodecane
acts as a diluent to lower the level of octylamine vapor pressure
for the purposes of this demonstration of the invention.
EXAMPLE 6
[0074] FIG. 12 illustrates the immunity of the present invention to
interference from water vapor. The hydrophobicity of the reverse
phase support greatly any possible effects from varying water vapor
in the atmosphere to be tested. For instance, as shown in FIG. 12,
a color fingerprint generated from exposure of the array to
n-hexylamine (0.86% in N.sub.2) was identical to that for
n-hexylamine spiked heavily with water vapor (1.2% H.sub.2O, 0.48%
hexylamine in N.sub.2). See scans 120, 122 and 124. The ability to
easily detect species in the presence of a large water background
represents a substantial advantage over mass-sensitive sensing
techniques or methodologies that employ polar polymers as part of
the sensor array. The color patterns shown in FIG. 12 are
summarized in Table 10 below.
10TABLE 10 Scan 120 Sn.sup.4+ - No Change Co.sup.3+ - Green
Cr.sup.3+ - Green Mn.sup.3+ - No Change Fe.sup.3+ - Red Co.sup.2+ -
No Change Cu.sup.2+ - No Change Ru.sup.2+ - No Change Zn.sup.2+ -
Green Ag.sup.2+ - No Change 2H.sup.+ (Free Base "FB") -- Dark Blue
Scan 122 Sn.sup.4+ - No Change Co.sup.3+ - Green Cr.sup.3+ - Green
Mn.sup.3+ - No Change Fe.sup.3+ - Red Co.sup.2+ - No Change
Cu.sup.2+ - No Change Ru.sup.2+ - Green (small dot) Zn.sup.2+ -
Green Ag.sup.2+ - No Change 2H.sup.+ (Free Base "FB") -- Dark Blue
Scan 124 Sn.sup.4+ - Bluish Circle Co.sup.3+ - Bluish Circle
Cr.sup.3+ - Bluish Circle
[0075]
11 Sn.sup.4+ - Bluish Circle Co.sup.3+ - Bluish Circle Cr.sup.3+ -
Bluish Circle Mn.sup.3+ - Bluish Circle Fe.sup.3+ - Bluish Circle
Co.sup.2+ - Bluish Circle Cu.sup.2+ - Bluish Circle Ru.sup.2+ -
Bluish Circle Zn.sup.2+ - Bluish Circle Ag.sup.2+ - Bluish Circle
2H.sup.+ (Free Base "FB") -- Bluish Circle
[0076] Additional Features of the Preferred Embodiments of the
Invention
[0077] Having demonstrated electronic differentiation, an important
further goal is the shape-selective distinction of analytes (e.g.,
n-hexylamine vs. cyclohexylamine). Functionalized metalloporphyrins
that limit steric access to the metal ion are candidates for such
differentiation. For instance, we have been able to control
ligation of various nitrogenous ligands to
dendrimer-metalloporphyrins and induce selectivities over a range
of more than 10.sup.4. As an initial attempt toward shape-selective
detection, we employed the slightly-hindered
tetrakis(2,4,6-trimethoxyphenyl)porphyrins (TTMPP) in our sensing
array. With these porphyrins, fingerprints for t-butylamine and
n-butylamine showed subtle distinctions, as did those for
cyclohexylamine and n-hexylamine. Using more hindered
metalloporphyrins, it is contemplated that the present invention
can provide greater visual differentiation. Such porphyrins include
those whose periphery is decorated with dendrimer, siloxyl, phenyl,
t-butyl and other bulky substituents, providing sterically
constrained pockets on at least one face (and preferably both) of
the porphyrin.
[0078] In a similar fashion, it is contemplated that the sensor
plates of the present invention can be used for the detection of
analytes in liquids or solutions, or solids. A device that detects
an analyte in a liquid or solution or solid can be referred to as
an artificial tongue. Proper choice of the metal complexes and the
solid support must preclude their dissolution into the solution to
be analyzed. It is preferred that the surface support repel any
carrier solvent to promote the detection of trace analytes in
solution; for example, for analysis of aqueous solutions, reverse
phase silica has advantages as a support since it will not be
wetted directly by water.
[0079] Alternative sensors in accordance with the present invention
may include any other dyes or metal complexes with intense
absorbance in the ultraviolet, visible, or near infrared spectra
that show a color change upon exposure to analytes. These
alternative sensors include, but are not limited to, a variety of
macrocycles and non-macrocycles such as chlorins and chlorophylls,
phthalocyanines and metallophthalocyanines, salen-type compounds
and their metal complexes, or other metal-containing dyes.
[0080] The present invention can be used to detect a wide variety
of analytes regardless of physical form of the analytes. That is,
the present invention can be used to detect any vapor emitting
substance, including liquid, solid, or gaseous forms, and even when
mixed with other vapor emitting substances, such solution mixtures
of substances.
[0081] The present invention can be used in combinatorial libraries
of metalloporphyrins for shape selective detection of substrates
where the substituents on the periphery of the macrocycle or the
metal bound by the porphyrin are created and then physically
dispersed in two dimensions by (partial) chromatographic or
electrophoretic separation.
[0082] The present invention can be used with chiral substituents
on the periphery of the macrocycle for identification of chiral
substrates, including but not limited to drugs, natural products,
blood or bodily fluid components.
[0083] The present invention can be used for analysis of biological
entities based on the surface proteins, oligosacharides, antigens,
etc., that interact with the metalloporphyrin array sensors of the
present invention. Further, the sensors of the present invention
can be used for specific recognition of individual species of
bacteria or viruses.
[0084] The present invention can be used for analysis of nucleic
acid sequences based on sequence specific the surface interactions
with the metalloporphyrin array sensors. The sensors of the present
invention can be used for specific recognition of individual
sequences of nucleic acids. Substituents on the porphyrins that
would be particularly useful in this regard are known DNA
intercalating molecules and nucleic acid oligomers.
[0085] The present invention can be used with ordinary flat bed
scanners, as well as portable miniaturized detectors, such as CCD
detectors with microarrays of dyes such as metalloporphyrins.
[0086] The present invention can be used for improved sensitivity,
automation of pattern recognition of liquids and solutions, and
analysis of biological and biochemical samples.
[0087] Superstructure Bonded to the Periphery of the Porphyrin
[0088] The present invention includes modified porphyrins that have
a super structure bonded to the periphery of the porphyrin. A super
structure bonded to the periphery of the porphyrin in accordance
with the present invention includes any additional structural
element or chemical structure built at the edge of the porphyrin
and bonded thereto.
[0089] The super structures can include any structural element or
chemical structure characterized in having a certain selectivity.
Those of skill in the art will recognize that the super structures
of the present invention include structures that are shape
selective, polarity selective, inantio selective, regio selective,
hydrogen bonding selective, and acid-base selective. This
structures can include siloxyl-substituted substituents,
nonsiloxyl-substituted substituents and nonsiloxyl-substituted
substituents, including but not limited to aryl substituents, alkyl
substituents, and organic, organometallic, and inorganic functional
group substituents.
[0090] Superstructure Bis-Pocket Porphyrins
[0091] A number of modified porphyrins have been synthesized to
mimic various aspects of the enzymatic functions of heme proteins,
especially oxygen binding (myoglobin and hemoglobin) and substrate
oxidation (cytochrome P-450). See Suslick, K. S.; Reinert, T. J. J.
Chem. Ed. 1985, 62, 974; Collman, J. P.; Zhang, X.; Lee, V. J.;
Uffelman, E. S.; Brauman, J. I. Science 1993, 261, 1404; Collman,
J. P.; Zhang, X. in Comprehensive Supramolecular Chemistry; Atwood,
J. L.; Davies, J. E. D.; MacNicol, D. D.; Vogtel, F. Eds.;
Pergamon: New York, 1996; vol. 5, pp. 1-32; Suslick, K. S.; van
Deusen-Jeffries, S. in Comprehensive Supramolecular Chemistry;
Atwood, J. L.; Davies, J. E. D.; MacNicol, D. D.; Vogtel, F. Eds.;
Pergamon: New York, 1996; vol.5, pp. 141-170; Suslick, K. S. in
Activation and Functionalization of Alkanes; Hill, C. L., ed.;
Wiley & Sons: New York, 1989; pp. 219-241. The notable property
of many heme proteins is their remarkable substrate selectivity;
the development of highly regioselective synthetic catalysts,
however, is still at an early stage. Discrimination of one site on
a molecule from another and distinguishing among many similar
molecules presents a difficult and important challenge to both
industrial and biological chemistry. See Metalloporphyrins in
Catalytic Oxidations; Sheldon, R. A. Ed. Marcel Dekker: New York,
1994). Although the axial ligation properties of simple synthetic
metalloporphyrins are well documented in literature, see Bampos,
N.; Marvaud, V.; Sanders, J. K. M. Chem. Eur. J. 1998, 4, 325;
Stibrany, R. T.; Vasudevan, J.; Knapp, S.; Potenza, J. A.; Emge,
T.; Schugar, H. J. J. Am. Chem. Soc. 1996, 118, 3980, size and
shape control of ligation to peripherally modified
metalloporphyrins has been largely unexplored, with few notable
exceptions, where only limited selectivities have been observed.
See Bhyrappa, P.; Vaijayanthimala, G.; Suslick, K. S. J. Am. Chem.
Soc. 1999, 121, 262; Imai, H.; Nakagawa, S.; Kyuno, E. J. Am. Chem.
Soc. 1992, 114, 6719.
[0092] The present invention includes the synthesis,
characterization and remarkable shape-selective ligation of
silylether-metalloporphyrin scaffolds derived from the reaction of
5,10,15,20-tetrakis(2',6'-dihydrox- yphenyl)porphyrinatozinc(II)
with t-butyldimethylsilyl chloride, whereby the two faces of the
Zn(II) porphyrin were protected with six, seven, or eight siloxyl
groups. This results in a set of three porphyrins of nearly similar
electronics but with different steric encumbrance around central
metal atom present in the porphyrin. Ligation to Zn by classes of
different sized ligands reveal shape selectivities as large as
10.sup.7.
[0093] A family of siloxyl-substituted bis-pocket porphyrins were
prepared according to the scheme of FIG. 13. The abbreviations of
the porhyrins that can be made in accordance with the scheme shown
in FIG. 13 are as follows:
[0094] Zn(TPP), 5,10,15,20-tetraphenylporphyrinatozinc(II);
[0095] Zn[(OH).sub.6PP],
5-phenyl-10,15,20-tris(2/,6/-dihydroxyphenyl)porp-
hyrinatozinc(II);
[0096] Zn[(OH).sub.8PP],
5,10,15,20-tetrakis(2/,6/-dihydroxyphenyl)porphyr-
inatozinc(II);
[0097] Zn(Si.sub.6PP),
5(phenyl)-10,15,20-trikis(2/,6/-disilyloxyphenyl)po-
rphyrinatozinc(II);
[0098] Zn(Si.sub.7OHPP),
5,10,15-trikis(2/,6/-disilyloxyphenyl)-20-(2/-hyd-
roxy-6/-silyloxyphenyl)porphyrinatozinc(II);
[0099] Zn(Si8PP),
5,10,15,20-tetrakis(2/,6/-disilyloxyphenyl)porphyrinatoz- inc(II).
The synthesis of Zn[(OH).sub.6PP], Zn(Si.sub.6PP), and Zn(Si8PP) is
detailed below. Zn[(OH).sub.6PP] and Zn[(OH).sub.8PP] were obtained
(see Bhyrappa, P.; Vaijayanthimala, G.; Suslick, K. S. J. Am. Chem.
Soc. 1999, 121, 262) from demethylation (see Momenteau, M.;
Mispelter, J.; Loock, B.; Bisagni, E. J. Chem. Soc. Perkin Trans.
1, 1983, 189) of corresponding free base methoxy compounds followed
by zinc(II) insertion. The methoxy porphyrins were synthesized by
acid catalysed condensation of pyrrole with respective
benzaldehydes following Lindsey procedures. See Lindsey, J. S.;
Wagner, R. W. J. Org. Chem. 1989, 54, 828. Metalation was done in
methanol with Zn(O.sub.2CCH.sub.3).sub.2. The t-butyldimethylsilyl
groups were incorporated into the metalloporphyrin by stirring a
DMF solution of hydroxyporphyrin complex with TBDMSiCl (i.e.,
t-butyldimethylsilyl chloride) in presence of imidazole. See Corey,
E. J; Venkateswarlu, A. J. Am. Chem. Soc. 1972, 94, 6190. The octa
(Zn(Si.sub.8PP)), hepta (Zn(Si.sub.7OHPP)), and hexa
(Zn(Si.sub.6PP)) silylether porphyrins were obtained from
Zn[(OH)gPP] and Zn[(OH).sub.6PP], respectively. The compounds were
purified by silica gel column chromatography and fully
characterized by UV-Visible, .sup.1H-NMR, HPLC, and MALDI-TOF
MS.
[0100] The size and shape selectivities of the binding sites of
these bis-pocket Zn silylether porphyrins were probed using the
axial ligation of various nitrogenous bases of different shapes and
sizes in toluene at 25.degree. C. Zn(II) porphyrins were chosen
because, in solution, they generally bind only a single axial
ligand. Successive addition of ligand to the porphyrin solutions
caused a red-shift of the Soret band typical of coordination to
zinc porphyrin complexes. There is no evidence from the electronic
spectra of these porphyrins for significant distortions of the
electronic structure of the porphyrin. The binding constants
(K.sub.eq) and binding composition (always 1:1) were evaluated
using standard procedures. See Collman, J. P.; Brauman, J. I.;
Doxsee, K. M.; Halbert, T. R.; Hayes, S. E.; Suslick, K. S. J. Am.
Chem. Soc. 1978, 100,2761; Suslick, K. S.; Fox, M. M.; Reinert, T.
J. Am. Chem. Soc. 1984, 106, 4522. The Kq values of the silylether
porphyrins with nitrogenous bases of different classes are compared
with the sterically undemanding Zn(TPP) in FIGS. 14a, 14b, and 14c.
It is worth noting the parallel between shape selectivity in these
equilibrium measurements and prior kinetically-controlled
epoxidation and hydroxylation. See Collman, J. P.; Zhang, X. in
Comprehensive Supramolecular Chemistry; Atwood, J. L.; Davies, J.
E. D.; MacNicol, D. D.; Vogtel, F. Eds.; Pergamon: New York, 1996;
vol. 5, pp. 1-32; Suslick, K. S.; van Deusen-Jeffries, S. in
Comprehensive Supramolecular Chemistry; Atwood, J. L.; Davies, J.
E. D.; MacNicol, D. D.; Vogtel, F. Eds.; Pergamon: New York, 1996;
vol. 5, pp. 141-170; Suslick, K. S. in Activation and
FunctionalizationofAlkanes; Hill, C. L., ed.; Wiley& Sons: New
York, 1989; pp.219-241; Bhyrappa, P.; Young, J.K.; Moore, J.S.;
Suslick, K. S. J. Am. Chem. Soc., 1996,118,5708-5711. Suslick, K.
S.; Cook, B. R. J. Chem. Soc., Chem. Comm. 1987, 200-202; Cook, B.
R.; Reinert, T. J.; Suslick, K. S. J. Am. Chem. Soc. 1986, 108,
7281-7286; Suslick, K. S.; Cook, B. R.; Fox, M. M. J. Chem. Soc.,
Chem. Commun. 1985, 580-582. The selectivity for equilibrated
ligation appears to be substantially larger than for irreversible
oxidations of similarly shaped substrates.
[0101] The binding constants of silylether porphyrins are
remarkably sensitive to the shape and size of the substrates
relative to Zn(TPP). See FIGS. 14a, 14b, and 14c. The binding
constants of different amines could be controlled over a range of
10.sup.1 to 10.sup.7 relative to Zn(TPP). It is believed that these
selectivities originate from strong steric repulsions created by
the methyl groups of the t-butyldimethylsiloxyl substituents. The
steric congestion caused by these bulky silylether groups is
pronounced even for linear amines and small cyclic amines (e.g.,
azetidine and pyrrolidine).
[0102] There are very large differences in K.sub.eq for porphyrins
having three versus four silylether groups on each face (e.g.,
hexa- vs. octa-silylether porphyrins), as expected based on obvious
steric arguments (see FIGS. 14a, 14b, and 14c). Even between the
hexa-over hepta-silylether porphyrins, however, there are still
substantial differences in binding behavior. It is believed that
this is probably due to doming of the macrocycle in the hexa- and
hepta-silylether porphyrins, which lessens the steric constraint
relative to the octasilylether porphyrin. Such doming will be
especially important in porphyrins whose two faces are not
identical. The free hydroxy functionality of the hepta-silylether
may play a role in binding of bi-functionalized ligands (e.g., free
amino acids); for the simple amines presented here, however, we
have no evidence of any special effects.
[0103] These silylether porphyrins showed remarkable selectivities
for normal, linear amines over their cyclic analogues. For a series
of linear amines (n-propylamine through n-decylamine), K.sub.eq
were very similar for each of the silylether porphyrins. In
comparison, the relative K.sub.eq for linear versus cyclic primary
amines (FIG. 14a, n-butylamine vs. cyclohexylamine) were
significantly different: K.sub.eq.sup.linear/K.sub.eq.sup.cyclic
ranges from 1 to 23 to 115 to >200 for Zn(TPP), Zn(Si.sub.6PP),
Zn(Si.sub.7OHPP), and Zn(SigPP), respectively. The ability to
discriminate between linear and cyclic compounds is thus
established.
[0104] A series of cyclic 2.degree. amines (FIG. 14b) demonstrate
the remarkable size and shape selectivities of this family of
bis-pocket porphyrins. Whereas the binding constants to Zn(TPP)
with those amines are virtually similar. In contrast, the K.sub.eq
values for silylether porphyrins strongly depend on the ring size
and its peripheral substituents. The effect of these
shape-selective binding sites is clear, even for compact aromatic
ligands with non-ortho methyl substituents (FIG. 14c).
[0105] The molecular structures of these silylether porphyrins
explains their ligation selectivity. The x-ray single crystal
structure of Zn(Si.sub.8PP) has been solved in the triclinic P lbar
space group. See Single crystal x-ray structure of Zn(Si8PP) shown
in FIG. 15. As shown in FIG. 15, Zn(Si.sub.6PP) (energy minimized
molecular model) and Zn(Si.sub.8PP) (single crystal x-ray
structure) have dramatically different binding pockets. In the
octasilylether porphyrin, the top access on both faces of the
porphyrin is very tightly controlled by the siloxyl pocket. In
contrast, the metal center of the hexasilylether porphyrin is
considerably more exposed for ligation.
[0106] FIG. 15 illustrates molecular models of Zn(Si.sub.6PP) (left
column) and Zn(Si.sub.8PP) (right column). The pairs of images from
top to bottom are cylinder side-views, side-views, and top-views,
respectively; space filling shown at 70% van der Waals radii; with
the porphyrin carbon atoms shown in purple, oxygen atoms shown in
red, silicon atoms in green, and Zn in dark red. The x-ray single
crystal structure of Zn(Si8PP) is shown; for Zn(Si.sub.6PP), an
energy-minimized structure was obtained using Cerius 2 from
MSI.
[0107] In summary, a series of bis-pocket siloxyl metalloporphyrin
complexes were prepared with sterically restrictive binding pockets
on both faces of the macrocycle. Ligation to Zn by various
nitrogenous bases of different sizes and shapes were investigated.
Shape selectivities as large as 10.sup.7 were found, compared to
unhindered metalloporphyrins. Fine-tuning of ligation properties of
these porphyrins was also possible using pockets of varying steric
demands. The shape selectivities shown here rival or surpass those
of any biological system.
[0108] Examples of Synthesis of Super Structures
[0109] Synthesis of
5-phenyl-10,15,20-tris(2/,6/-dihydroxy-phenyl)-porphyr-
inatozinc(II), Zn[(OH).sub.6PP]:
[0110] The free base 5-phenyl-10,1
5,20-tris(2/,6/-dimethoxyphenyl)-porphy- rin was synthesized by
Lewis acid catalyzed condensation of 2,6-dimethoxybezaldehyde and
benzaldehyde with pyrrole (3:1:4 mole ratio) following the Lindsey
procedure. See Lindsey, J. S.; Wagner, R. W. J. Org. Chem. 1989,
54, 828. The mixture of products thus formed was purified by silica
gel column chromatography (if necessary, using CH.sub.2Cl.sub.2 as
eluant). The isolated yield of the desired product was found to be
7% (wrt pyrrole used). The corresponding hydroxyporphyrins were
obtained by demethylation with pyridine hydrochloride. See
Momenteau, M.; Mispelter, J.; Loock, B.; Bisagni, E. J. Chem. Soc.
Perkin Trans. 1, 1983, 189. After typical work-up known to those
skilled in the art, the crude compound was purified by silica gel
column chromatography using ethylacetate as eluant. The first
fraction was Zn[(OH).sub.6PP], which was collected and the solvent
was removed. The yield of the product was 90% (based on starting
hydroxyporphryin). .sup.1H NMR of H.sub.2[(OH).sub.6PP] in
acetone-d.sub.6 (pPm): 8.96-8.79 (m, 8H, b-pyrrole H), 8.24 (m, 2H,
o-H 5-Phenyl), 8.07 and 8.02 (2s, 6H, --OH), 7.83 (m, 3H, m,p-H
5-Phenyl), 7.50 (t, 3H, p-H hydroxyphenyl), 6.90 (d, 6H, m-H
hydroxyphenyl), -2.69 (s, 2H, imino-H). Elemental analysis, calcd.
for C.sub.44H.sub.30O.sub.6N.sub.4.H.sub.2O: C=72.5, H=4.4 and
N=7.7%. Found C=72.7, H=4.4 and N=7.4%. The compound showed
molecular ion peak at 711 (m/z calcd. for
C.sub.44H.sub.30O.sub.6N.sub.4=- 710) in FAB-MS.
[0111] The Zn derivative was obtain by stirring methanol solution
of H.sub.2[(OH).sub.6PP] with excess
Zn(O.sub.2CCH.sub.3).sub.22H.sub.2O for 1 hour. Methanol was
evaporated to dryness and the residue was dissolved in
ethylacetate, washed with water, and the organic layer passed
through anhyd. Na.sub.2SO.sub.4. The concentrated ethylacetate
solution was passed through a silica gel column and the first band
was collected as the desired product. The yield of the product was
nearly quantitative. .sup.1H NMR of Zn(OH).sub.6PP in
acetone-d.sub.6 (ppm): 8.95-8.79 (m, 8H, b-pyrrole H), 8.22 (m, 2H,
o-H 5-Phenyl), 7.79 (m, 3H, m,p-H 5-Phenyl), 7.75 and 7.65 (2s, 6H,
--OH), 7.48 (t, 3H, p-H hydroxyphenyl), 6.88 (d, 6H, m-H
hydroxyphenyl). Elemental analysis, calcd. for
ZnC.sub.44H.sub.28O.sub.6N.sub.4.H.sub.2O: C=66.7, H=3.8, N=7.1 and
Zn=8.3%. Found C=66.4, H=3.8, N=6.7 and Zn=8.2%. The compound
showed molecular ion peak at 774 (m/z calcd. for
ZnC.sub.44H.sub.28O.sub.6N.sub.- 4=773) in FAB-MS.
[0112] Synthesis of
5-phenyl-10,15,20-tris(2/,.sup.6/-disilyloxyphenyl)-po-
rphyrinatozinc(II), Zn(Si.sub.6PP):
[0113] The hexasilylether porphyrin was synthesized by stirring a
DMF solution of
5-phenyl-10,15,20-tris(2/,6/-dihydroxyphenyl)-porphyrinatozin-
c(II) (100 mg, 0.13 mmol) with t-butyldimethyl silylchloride (1.18
g, 7.8 mmol) in presence of imidazole (1.2 g, 17.9 mmol) at
60.degree. C. for 24 h under nitrogen. After this period the
reaction mixture was washed with water and extracted in CHCl.sub.3.
The organic layer was dried over anhyd. Na.sub.2SO.sub.4. The crude
reaction mixture was loaded on a short silica gel column and eluted
with mixture of CHCl.sub.3/petether (1:1, v/v) to get rid of
unreacted starting material and lower silylated products. The
desired compound was further purified by running another silica gel
column chromatography using mixture of CHCl.sub.3/petether (1:3,
v/v) as eluant. The yield of the product was 60% based on starting
hydroxyporphyrin.
[0114] .sup.1H NMR in chloroform-d (ppm): 8.94-8.82 (m, 8H,
b-pyrrole H), 8.20 (m, 2H, o-H 5-Phenyl), 7.74 (m, 3H, m,p-H
5-Phenyl), 7.49 (t, 3H, p-H hydroxyphenyl), 6.91 (t, 6H, m-H
hydroxyphenyl), -0.02 and -0.34 (2s, 54H, t-butyl H), -0.43, -0.78
and -1.01 (3s, 36H, methyl H).
[0115] Elemental analysis, calcd. for
ZnC.sub.80H.sub.112O.sub.6N.sub.4Si.- sub.6: C=65.8, H=7.7, N=3.8,
Si=11.5 and Zn=4.5%. Found C=65.5, H=7.7, N=3.8, Si=11.2 and
Zn=4.4%. The low resolution MALDI-TOF mass spectrum showed
molecular ion peak at 1457 (m/z calcd. for ZnC.sub.80H.sub.112O.su-
b.6N.sub.4Si.sub.6=1458).
[0116] Synthesis of
5,10,15-tris(2/,6/-disilyoxyphenyl)-20-(2/-hydr-oxy-6/-
-silyloxyphenyl)porphyrinatozinc(II), [Zn(Si.sub.7OHPP)], and
5,10,15,20-tetrakis(2/,6/-disilyloxyphenyl)porphy-rinato-zinc(II),
[Zn(Si.sub.8PP)]:
[0117] The synthesis of precursor porphyrin
5,10,15,20-tetrakis-(2/,6/-dih- ydroxyphenyl)porphyrin and its Zn
derivative was accomplished as reported earlier. See Bhyrappa, P.;
Vaijayanthimala, G.; Suslick, K. S. J. Am. Chem. Soc. 1999,121,262.
The hepta- and octa-silylether porphyrins were synthesized by
stirring DMF solution of 5,10,15,20-tetrakis(2/,6/-dihydro-
xyphenyl)porphyrinatozinc(II) (100 mg, 0.12 mmol) with
t-butyldimethyl silylchloride (1.45 g, 9.6 mmol) in presence of
imidazole (1.50 g, 22.1 mmol) at 60.degree. C. for 24 h under
nitrogen. After usual work-up the mixture of crude products were
loaded on a silica gel column and eluted with mixture of
CHCl.sub.3/pet. ether (1: 1, v/v) to remove unreacted starting
material and lower silylated products. The major product isolated
from this column is a mixture of hepta- and octa-silylated
porphyrins. The mixture thus obtained was further purified by
another silica gel column chromatography using mixture of
CHCl.sub.3/pet. ether (1:3, v/v) as eluant. The first two bands
were isolated as octa- and hepta-silylether porphyrin at 45% and
30% yield, respectively. Both the compounds were characterized by
UV-Visible, .sup.1H NMR and MALDI-TOF spectroscopic techniques. The
homogeneity of the sample was verified by HPLC.
[0118] For Zn(Si.sub.7OHPP), .sup.1HNMR in chloroform-d (ppm): 8.91
(m, 8H, b-pyrrole H), 7.50 (m, 4H, p-H), 7.01-6.81 (m, 8H, m-H),
0.11 to -0.03 (12s, 105H, t-butyl and methyl H). Elemental
analysis, caled. for ZnC.sub.86H.sub.126O.sub.8N.sub.4Si.sub.7:
C=64.3, H=7.8, N=3.5, Si=12.3 and Zn=4.1%. Found C=63.6, H=8.1,
N=3.5, Si=12.1 and Zn=3.9%. The low resolution MALDI-TOF mass
spectrum showed molecular ion peak at 1604 (m/z calcd. for
ZnC.sub.86H.sub.126O.sub.8N.sub.4Si.sub.7=1604).
[0119] For Zn(Si.sub.8PP), .sup.1H NMR in chloroform-d (ppm): 8.89
(s, 8H, b-pyrrole H), 7.49 (t, 4H, p-H), 6.92 (d, 8H, m-H), 0.09
(s, 72H, t-butyl H), -1.01 (s, 48H, methyl H). Elemental analysis,
calcd. for ZnC.sub.92H.sub.140O.sub.8N.sub.4Si.sub.8: C=64.2,
H=8.1, N=3.3, Si=13.1 and Zn=3.8%. Found C=63.5, H=8.4, N=3.3,
Si=12.8 and Zn=4.0%. The low resolution MALDI-TOF mass spectrum
showed molecular ion peak at 1719 (m/z calcd. for
ZnC.sub.92H.sub.140O.sub.8N.sub.4Si.sub.8=1718).
[0120] Additional Features of the Preferred Embodiments of the
Invention
[0121] Having demonstrated electronic differentiation and
shape-selective distinction of analytes that bind to metal ions in
metallodyes, an important further goal is the differentiation of
analytes that do not bind or bind only weakly to metal ions. Such
analytes include acidic compounds, such as carboxylic acids, and
certain organic compounds lacking ligatable functionality, such as
simple alkanes, arenes, some alkenes and alkynes (especially if
sterically hindered), and molecules sterically hindered as to
preclude effective ligation. One approach that has been developed
to achieve this goal in accordance with the present invention is to
include in the sensor array other chemoresponsive dyes, including
pH sensitive dyes (i.e., pH indicator or acid-base indicator dyes
that change color upon exposure to acids or bases), and/or
solvatochromic dyes (i.e., dyes that change color depending upon
the local polarity of their micro-environment).
[0122] It has been discovered that the addition of pH sensitive
dyes and solvatochromic dyes to other arrays containing
metalloporphyrins as described above expands the range of analytes
to which the arrays are sensitive, improves sensitivities to some
analytes, and increases the ability to discriminate between
analytes.
[0123] The present invention includes an artificial nose comprising
an array, the array comprising at least a first dye and a second
dye deposited directly onto a single support in a predetermined
pattern combination, the combination of the dyes in the array
having a distinct and direct spectral absorbance or reflectance
response to an analyte wherein the first dye and the second dye are
selected from the group consisting of chemoresponsive dyes, and the
second dye is distinct from the first dye. In a preferred
embodiment, the first dye is selected from the group consisting of
porphyrin, chlorin, chlorophyll, phtahlocyanine, and salen and
their metal complexes. In another preferred embodiment, the second
dye is selected from the group of dyes consisting of acid-base
indicator dyes and solvatochromic dyes.
[0124] The present invention includes a method of detecting an
analyte comprising the steps of: (a) forming an array of at least a
first dye and a second dye deposited directly onto a single support
in a predetermined pattern combination, the combination of the dyes
in the array having a distinct and direct spectral absorbance or
reflectance response to an analyte wherein the first dye and the
second dye are selected from the group consisting of
chemoresponsive dyes, and the second dye is distinct from the first
dye; (b) subjecting the array to an analyte; (c) inspecting the
array for a distinct and direct spectral absorbance or reflectance
response; and (d) correlating the distinct and direct spectral
response to the presence of the analyte. In a preferred method, the
first dye is selected from the group consisting of porphyrin,
chlorin, chlorophyll, phtahlocyanine, and salen and their metal
complexes. In another preferred method, the second dye is selected
from the group of acid-base indicator dyes and solvatochromic
dyes.
[0125] The present invention includes an artificial tongue
comprising an array, the array comprising at least a first dye and
a second dye deposited directly onto a single support in a
predetermined pattern combination, the combination of the dyes in
the array having a distinct and direct spectral absorbance or
reflectance response to an analyte wherein the first dye and the
second dye are selected from the group consisting of
chemoresponsive dyes, and the second dye is distinct from the first
dye. In a preferred embodiment, the first dye is selected from the
group consisting of porphyrin, chlorin, chlorophyll,
phtahlocyanine, and salen and their metal complexes. In another
preferred embodiment, the second dye is selected from the group of
dyes consisting of acid-base indicator dyes and solvatochromic
dyes.
[0126] Chemoresponsive dyes are those dyes that change color, in
either reflected or absorbed light, upon changes in their chemical
environment. Three general classes of chemoresponsive dyes are (1)
Lewis acid/base dyes, (2) pH indicator dyes, and (3) solvatochromic
dyes.
[0127] Lewis acid/base dyes are those dyes that contain a Lewis
acidic or basic center (where a Lewis acid is an electron pair
acceptor and a Lewis base is an electron pair donor) and change
color in response to changes in the Lewis acidity or basicity of
their environment. A specific set of Lewis acid/base dyes includes
dyes such as porphyrin, chlorin, chlorophyll, phtahlocyanine, and
salen and their metal complexes.
[0128] pH indicator or acid-base indicator dyes are those that
change color in response to changes in the proton acidity or
basicity (also called Bronsted acidity or basicity) of their
environment. A specific set of pH indicator dyes include
Chlorphenol Red, Bromocresol Green, Bromocresol Purple, Bromothymol
Blue, Phenol Red, Thymol Blue, Cresol Red, Alizarin, Mordant
Orange, Methyl Orange, Methyl Red, Congo Red, Victoria Blue B,
Eosin Blue, Fat Brown B, Benzopurpurin 4B, Phloxine B, Orange G,
Metanil Yellow, Naphthol Green B, Methylene Blue, Safranine O,
Methylene Violet 3RAX, Sudan Orange G, Morin Hydrate, Neutral Red,
Disperse Orange 25, Rosolic Acid, Fat Brown RR, Cyanidin chloride,
3,6-Acridineamine, 6'-Butoxy-2,6-diamino-3,3'-azodipyridine,
para-Rosaniline Base, Acridine Orange Base, Crystal Violet, and
Malachite Green Carbinol Base.
[0129] Solvatochromic dyes are those that change color in response
to changes in the general polarity of their environment, primarily
through strong dipole-dipole interactions. To some extent, all dyes
inherently are solvatochromic, although some are much more
responsive than others. A specific set of highly responsive
solvatochromic dyes include Reichardt's Dye and Nile Red.
[0130] It has been discovered that the following pH indicator
(i.e., acid-base indicator) dyes and solvatochromic dyes are useful
to expand the range of analytes to which the arrays containing
metalloporphyrins are sensitive, improve sensitivities to some
analytes, and increase the ability to discriminate between
analytes. Those skilled in the art will recognize that other
modifications and variations in the choice of such auxiliary dyes
may be made in addition to those described and illustrated herein
without departing from the spirit and scope of the present
invention. Accordingly, the choice of dyes described and
illustrated herein should be understood to be illustrative only and
not limiting upon the scope of the present invention.
[0131] Chlorphenol Red
[0132] Molecular Formula: Cl.sub.9H.sub.12Cl.sub.2O.sub.5S
[0133] Molecular Weight: 423.28
[0134] CAS: 4430-20-0
[0135] Transition interval: pH 4.8 (yellow) to pH 6.7 (violet)
[0136] Bromocresol Green
[0137] Synonyms: 3',3",5',5"Tetrabromo-m-cresolsulfonphthalein;
Bromcresol Green
[0138] Molecular Formula: C.sub.21H.sub.14Br.sub.4O.sub.5S
[0139] Molecular Weight: 698.04
[0140] CAS: 76-60-8
[0141] pH=3.8 yellow
[0142] =5.4 blue
[0143] Bromocresol Purple
[0144] Synonyms: 5',5" dibromo-m-cresolsulfonphthalein; Bromcresol
Purple
[0145] Molecular Formula: C.sub.21H.sub.16Br.sub.2O.sub.5S
[0146] Molecular Weight: 698.04
[0147] CAS:1 15-40-2
[0148] pH=5.2 yellow
[0149] =6.8 blue
[0150] Bromothymol Blue
[0151] Synonyms: 3',3"-Dibromothymolsulfonphthalein; Bromthymol
Blue
[0152] Molecular Formula: C.sub.27H.sub.28Br.sub.2O.sub.5S
[0153] Molecular Weight: 624.41
[0154] CAS: 76-59-5
[0155] pH=6.0 yellow
[0156] =7.6 blue
[0157] Phenol Red
[0158] Synonyms: Phenolsulfonphthalein
[0159] Molecular Formula: C.sub.19H.sub.14O.sub.5S
[0160] Molecular Weight: 354.38
[0161] CAS: 143-74-8
[0162] pH=6.8 yellow
[0163] =8.2 red
[0164] Thymol Blue
[0165] Synonyms: Thymolsulfonphthalein
[0166] Molecular Formula: C.sub.27H.sub.30O.sub.5S
[0167] Molecular Weight: 466.60
[0168] CAS: 76-61-9
[0169] pH=1.2 red
[0170] =2.8 yellow
[0171] =8 yellow
[0172] =9.2 blue
[0173] Cresol Red
[0174] Synonyms: Phenol,
4,4'-(1,1-dioxido-3H-2,1-benzoxathiol-3-ylidene)b-
is[2-methyl-(9CI)]
[0175] Molecular Formula: C.sub.21H.sub.18O.sub.5S
[0176] Molecular Weight: 382.43
[0177] CAS: 1733-12-6
[0178] pH 1.8 (orange) to pH 2.0 (yellow); Transition interval
(alkaline): pH 7.0 (yellow) to pH 8.8 (violet)
[0179] Alizarin
[0180] Synonyms: 1,2-Dihydroxyanthraquinone, 9,10-Anthracenedione,
1,2-dihydroxy-(9CI)
[0181] Molecular Formula: C.sub.14H.sub.8O.sub.4
[0182] Molecular Weight: 240.22
[0183] CAS: 72-48-0
[0184] pH=5.5 yellow
[0185] =6.8 red
[0186] =10.1 red
[0187] =12.1 violet
[0188] Mordant Orange 1
[0189] Synonyms: Alizarin Yellow R, C.I. 14030,
5-(4-nitrophenylazo)salicy- lic acid
[0190] Molecular Formula: C.sub.13H.sub.9N.sub.3O.sub.5
[0191] Molecular Weight: 287.23
[0192] CAS: 2243-76-7
[0193] Methyl Orange
[0194] Synonyms: 4-(p-[Dimethylamino]phenylazo)benzenesulfonic
acid, sodium salt
[0195] Acid Orange 52
[0196] Molecular Formula: C.sub.14Hl.sub.4N.sub.3O.sub.3SNa
[0197] Molecular Weight: 327.3
[0198] pH 3.0 (pink)-pH 4.4 (yellow)
[0199] Methyl Red
[0200] Synonyms: 4-Dimethylaminoazobenzene-2'carboxylicacid;
2-(4-Dimethylaminophenylazo)-benzoic acid
[0201] Molecular Formula: C.sub.15H.sub.15N.sub.3O.sub.2
[0202] Molecular Weight: 269.31
[0203] CAS: 493-52-7
[0204] pH=4.2 pink
[0205] =6.2 yellow
[0206] Reichardt's Dye
[0207] Synonyms:
[2,6-diphenyl-4-(2,4,6-triphenylpyridinio)phenolate]
[0208] Molecular Formula: C.sub.41H.sub.29NO
[0209] Molecular Weight: 551.69
[0210] CAS: 10081-39-7
[0211] Nile Red
[0212] Synonyms: 5H-Benzo[a]phenoxazin-5-one,
9-(diethylamino)-(7CI, 8CI, 9CI),
9-(Diethylamino)-5H-benzo[a]phenoxazin-5-one; Nile Blue A
oxazone
[0213] Molecular Formula: C.sub.20H.sub.18N.sub.2O.sub.2
[0214] Molecular Weight: 318.38
[0215] CAS: 7385-67-3
[0216] Congo Red
[0217] Molecular Formula: C.sub.32H.sub.24N.sub.6O.sub.6S2
Na.sub.2
[0218] Molecular Weight: 696.67
[0219] CAS: 573-58-0
[0220] pH range: blue 3.1-4.9 red
[0221] Victoria Blue B
[0222] Synonyms: Basic Blue 26, C.I. 44045
[0223] Molecular Formula: C.sub.33H.sub.32ClN.sub.3
[0224] Molecular Weight: 506.10
[0225] CAS: 2580-56-5
[0226] Eosin Blue
[0227] Synonyms: (Acid Red 91, C.I. 45400,
4',5'-dibromo-2',7'-dinitrofluo- rescein, disodium salt)
[0228] Molecular Formula: C.sub.20H.sub.8Br.sub.2N.sub.2O.sub.9
[0229] Molecular Weight: 624.08
[0230] CAS: 548-24-3
[0231] Fat Brown B
[0232] Synonyms: Solvent red 3
[0233] Molecular Formula: C.sub.18H.sub.16N.sub.2O.sub.2
[0234] Molecular Weight: 292.3
[0235] CAS: 6535-42-8
[0236] Benzopurpurin 4B
[0237] Synonyms: (C.I. 23500, Direct Red 2)
[0238] Molecular Formula: C.sub.34H.sub.28N.sub.6O.sub.6S.sub.2
[0239] Molecular Weight: 724.73
[0240] CAS: 992-59-6
[0241] pH range: violet 1.2-3.8 yellow
[0242] Phloxine B
[0243] Molecular Formula:
C.sub.20H.sub.4Br.sub.4Cl.sub.4O.sub.5
[0244] CAS: 18472-87-2
[0245] pH range: colorless 2.1-4.1 pink
[0246] Orange G
[0247] Synonyms: 1-Phenylazo-2-naphthol-6,8-disulfonic acid
disodium salt
[0248] Molecular Formula:
C.sub.16H.sub.10N.sub.2Na.sub.2O.sub.7S.sub.2
[0249] Molecular Weight: 452.
[0250] pH range: yellow 11.5-14.0 pink
[0251] Metanil Yellow
[0252] Synonyms: (Acid Yellow 36, C.I. 13065)
[0253] Molecular Formula: C.sub.18H.sub.15N.sub.3O.sub.3S Na
[0254] Molecular Weight: 375.38
[0255] CAS: 587-98-4
[0256] pH 1.5 (red) to pH 2.7 (yellow)
[0257] Naphthol Green B
[0258] Synonyms: (Acid Green 1, C.I. 10020)
[0259] Molecular Formula: C.sub.10H.sub.7NO.sub.5S
[0260] Molecular Weight: 878.47
[0261] CAS: 19381-50-1
[0262] Methylene Blue
[0263] Synonyms: (Basic Blue 9, C.I. 52015)
[0264] Molecular Formula: C.sub.16H.sub.18ClN.sub.3S
[0265] Molecular Weight: 373.90
[0266] CAS: 7220-79-3
[0267] Safranine O
[0268] Synonyms: (C.I. 50240,
3,7-diamino-2,8-dimethyl-5-phenylphenazinium chloride)
[0269] Molecular Formula: C.sub.20H.sub.19ClN.sub.4
[0270] Molecular Weight: 350.85
[0271] CAS: 477-73-6
[0272] Methylene Violet 3RAX
[0273] Synonyms: [3-amino-7-(diethylamino)-5-phenylphenazinium
chloride, C.I. 50206, N,N-diethylphenosafranine]
[0274] Molecular Formula: C.sub.22H.sub.23ClN.sub.4
[0275] Molecular Weight: 378.91
[0276] CAS: 4569-86-2
[0277] Sudan Orange G
[0278] Synonyms: [C.I. 11920, 4-(phenylazo)resorcinol, Solvent
Orange 1]
[0279] Molecular Formula:
C.sub.6H.sub.5N.dbd.NC.sub.6H.sub.3-1,3-(OH).sub- .2
[0280] Molecular Weight: 214.22
[0281] CAS: 2051-85-6
[0282] Morin Hydrate
[0283] Synonyms: (2',3,4',5,7-pentahydroxyflavone)
[0284] Molecular Formula: C.sub.15H.sub.10O.sub.7
[0285] Molecular Weight: 302.24
[0286] Neutral Red
[0287] Molecular Formula: C.sub.15H.sub.16 N.sub.4.HCl
[0288] Molecular Weight: 288.78
[0289] CAS: 553-24-2
[0290] pH=6.8 red
[0291] =8.0 yellow
[0292] Disperse Orange 25
[0293] Molecular Formula: C.sub.17H.sub.17 N.sub.5O.sub.2
[0294] Molecular Weight: 323.36
[0295] CAS: 31482-56-1
[0296] Rosolic Acid
[0297] Molecular Formula: C.sub.20H.sub.16O.sub.3
[0298] Molecular Weight: 290.32
[0299] CAS: 603-45-2
[0300] pH=5.0 yellow
[0301] =6.8 pink
[0302] Fat Brown RR
[0303] Molecular Formula: C.sub.16H.sub.14N.sub.4
[0304] Molecular Weight: 262.32
[0305] CAS: 6416-57-5
[0306] Cyanidin Chloride
[0307] Molecular Formula: C15H11O6.Cl
[0308] Molecular Weight: 322.7
[0309] CAS: 528-58-5
[0310] 3,6-Acridineamine
[0311] Molecular Formula: C.sub.13H.sub.11N.sub.3
[0312] Molecular Weight: 209.25
[0313] CAS Number: 92-62-6
[0314] 6'-Butoxy-2,6-diamino-3,3'-azodipyridine
[0315] Synonym: Azodipyridine
[0316] Molecular Formula: C.sub.14H.sub.18N.sub.6O
[0317] Molecular Weight: 286.34
[0318] CAS: 617-19-6
[0319] para-Rosaniline Base
[0320] Synonym: Rosaniline
[0321] Molecular Formula: C.sub.19H.sub.19N.sub.3O
[0322] Molecular Weight: 305.4
[0323] CAS: 25620-78-4
[0324] Acridine Orange Base
[0325] Molecular Formula: C.sub.17H.sub.19N.sub.3
[0326] Molecular Weight: 265.36
[0327] CAS: 494-38-2
[0328] Crystal Violet
[0329] Molecular Formula: C.sub.25H.sub.30N.sub.3Cl
[0330] Molecular Weight: 407.99
[0331] CAS: 548-62-9
[0332] pH=0 yellow
[0333] =1.8 blue
[0334] Malachite Green Carbinol Base
[0335] Molecular Formula: C.sub.23H.sub.26N.sub.2O
[0336] Molecular Weight: 346.48
[0337] CAS: 510-13-4
[0338] pH=0.2 yellow
[0339] =1.8 blue-green
[0340] In a preferred embodiment, a low volatility liquid, e.g., a
plasticizer, is used in an array of the present invention to keep
the dyes in the array from crystallizing and to enhance then
response of the array to an analyte. Examples of suitable low
volatility liquids include, but are not limited to DOW CORNING 704
silicone diffusion pump fluid (Molecular Weight: 484.82, Density:
1.070, CAS Number: 3982-82-9), and diundecyl phthalate (Molecular
Weight: 474.73, Density: 0.950, CAS Number: 3648-20-2, Formula:
C.sub.30H.sub.50O.sub.4, Boiling Point (.degree. C.): 523 at 760
torr), dibutyl phthalate (Molecular Weight: 278.4, Density: 1.048,
CAS Number: 84-74-2, Formula: C.sub.16H.sub.22O.sub.4, Boiling
Point (.degree. C.): 340 at 760 torr), diisopropyl phthalate
(Molecular Weight: 250.3, Density: 1.063, CAS Number: 605-45-8,
Formula: C.sub.14H.sub.18O.sub.4), squalane (Molecular Weight:
422.83, Density: 0.810, CAS Number: 111-01-3, Formula:
C.sub.30H.sub.62, Boiling Point (.degree. C.): 176 at 0.05 torr),
triethylene glycol dimethyl ether (synonym: Trigluyme, Molecular
Weight: 178.23, Density: 0.986, CAS Number: 112-49-2, Formula:
C.sub.8H.sub.18O.sub.4, Boiling Point (.degree. C.): 216 at 760
torr), and tetraethlyene glycol dimethyl ether (synonym:
Tetraglyme, (Molecular Weight: 222.28, Density: 1.009, CAS Number:
143-24-8, Formula: C.sub.10H.sub.22O.sub.5, Boiling Point (.degree.
C.): 275-276at 760 torr).
[0341] FIG. 16 illustrates an array containing illustrative
examples of porphyrin, metalloporphyrin, acid-base indicator, and
solvatochromatic dyes. Typical sizes can range from 0.5 mm to 2 cm
on a side. Linear, hexagonal, or rectangular arrays are also easily
used. From left to right and top to bottom the identities and
colors of the dyes used in the illustrative example of FIG. 16 are
listed in Table 11 as follows (the exact colors depend, among other
things, upon scanner settings).
12TABLE 11 (Summarizing the Dyes and Colors in FIG. 16, i.e., "Dye
- Color") SnTPPCl.sub.2 - CoTPP - CrTPPCl - MnTPPCl - FeTPPCl -
Light CuTPP - Light Green Peach Green Green Brownish Green Salmon
AgTPP - NiTPP - InTPPCL - IrTPPCl - ZnTPP - Salmon FeTFPPCl -
Salmon Pink Tan Pink Olive ZnSi.sub.6PP - ZnSi.sub.7OHPP -
ZnSi.sub.8PP - H.sub.2TPP - H.sub.2FPP - Light Alizarin basic -
Pink Deep Pink Pink Carmel Brown Violet Me Red - BCP - Dark
BCPbasic - BTB - Dark BTB basic - Blue Ph Red basic - Orange Green
Blue Yellow Lavender Nile Red - BCG - Blue BCG basic - CresRed -
CresRed basic - CP Red - Violet Blue Brownish Purple Purple Purple
R Dye - TB - Yellow TB basic - MeOr - MeOr basic - CP Red basic -
Light Blue Greenish Yellow Orangish Brown Bluish Gray Purple where
TPP = 5,10,15,20-tetraphenylporphyrinate(-2); Zn(Si.sub.6PP) =
5(phenyl)-10,15,20-trikis(2',6'-disilyloxyphenyl)porphyr-
inatozinc(II); Zn(Si.sub.7OHPP) = 5,10,15-trikis(2',6',disilyloxyp-
henyl)-20-(2'-hydroxy-6'-siloxyphenyl)porphyrinatozinc(II);
Zn(Si.sub.8PP) =
5,10,15,20-tetrakis(2',6'-disilyloxyphenyl)porphyrinatoz- inc(II);
Me Red = Methyl Red; BCP = Bromocresol Purple; BTB = Bromothymol
Blue; Ph Red = Phenol Red; BCG = Bromocresol Green; CresRed =
Cresol Red; CP Red = Chlorophenol Red; R Dye = Reichardt's Dye; TB
= Thymol Blue; MeOr = Methyl Orange; and basic indicates the
addition of KOH until the color of the basic form of the indicator
dye was observed. Note: DOW CORNING 704 silicone diffusion pump
fluid (Molecular Weight: 484.82, Density: 1.070, CAS Number:
3982-82-9) was added to all porphyrin solutions: 40 .mu.l/ml.
[0342] FIG. 17 illustrates the response of the array described in
FIG. 16 to acid vapors, specifically formic acid, acetic acid,
iso-valeric acid, and 3-methyl-2-hexenoic acid. As shown in FIG. 17
and summarized in Table 12 below, the color changes of each dye in
response to a particular analyte are shown as color difference
maps, as follows (the exact colors depend, among others things,
upon scanner settings). The color changes are derived simply by
comparing the before exposure and after exposure colors and
subtracting the two images (i.e., the absolute value of the
difference of the red values becomes the new red value in the color
difference map; etc. for green values and blue values). If there is
no change in the red, green, and blue color values of a dye in the
after-exposure image, then the color difference map will show black
(i.e., red value =green value =blue value =0).
13TABLE 12 (Summarizing the Dyes and Color Changes in FIG. 17, i.e.
"Dye - Difference Map Color") (Analyte: Formic Acid 140 ppb)
SnTPPCl.sub.2 - CoTPP - CrTPPCl MnTPPCl FeTPPCl - CuTPP - Black
Black (no Black Black Faint Blue Black (no (no change) (no (no
Periphery change) change) change) change) AgTPP - NiTPP - InTPPCL -
IrTPPCl - ZnTPP - FeTFPPCl - Black (no Black (no Black Black (no
Black (no Black (no change) change) (no change) change) change)
change) ZnSi.sub.6PP - ZnSi.sub.7OHPP - ZnSi.sub.8PP - H.sub.2TPP -
H.sub.2FPP - Alizarin basic - Black (no Black (no Black (no Black
(no Black (no Dark Blue change) change) change) change) change) Me
Red - BCP - BCP basic - BTB - BTB basic - Ph Red basic - Black (no
Yellow White Black (no Red Green change) change) Periphery w/Yellow
Center Nile Red - BCG - BCG CresRed - CresRed CP Red - Black (no
Black (no basic - Black (no basic - Light Black (no change) change)
Dark change) Green change) Purple R Dye - TB - Black TB basic -
MeOr - MeOr basic - CP Red basic - Black (no (no change) Black (no
Green and Dark Yellow change) change) Purple Purple Periphery and
Purple center (Analyte: Formic Acid 210 ppb) SnTPPCl.sub.2 - CoTPP
- CrTPPCl - MnTPPCl FeTPPCl - CuTPP - Black Black Black (no Black
(no Black (no Black (no (no change) (no change) change) change)
change) change) AgTPP - NiTPP - InTPPCL - IrTPPCl - ZnTPP - Black
FeTFPPCl - Black (no Black (no Black (no Black (no (no change)
Black (no change) change) change) change) change) ZnSi.sub.6PP -
ZnSi.sub.7OH ZnSi.sub.8PP - H.sub.2TPP - H.sub.2FPP - Black
Alizarin basic - Black (no PP - Black (no Black (no (no change)
Black (no change) Black (no change) change) change) change) Me Red
- BCP - BCP basic - BTB - BTB basic - Ph Red basic - Black (no Red
Yellow Black (no Red Green change) Periphery and change) Red Center
Nile Red - BCG - BCG basic - CresRed - CresRed basic - CP Red -
Black Black (no Black (no Red periphery Black (no Green (no change)
change) change) change) R Dye - TB - TB basic - MeOr - MeOr basic -
CP Red basic - Black (no Black (no Black (no Black (no Black (no
Yellow change) change) change) change) change) Periphery and Purple
Center (Analyte: Formic Acid 340 ppb) SnTPPCl.sub.2 - CoTPP -
CrTPPCl - MnTPPCl - FeTPPCl - CuTPP - Black Black Black (no Black
(no Black (no Black (no (no change) (no change) change) change)
change) change) AgTPP - NiTPP - InTPPCL - IrTPPCl - ZnTPP -
FeTFPPCl - Black Black (no Black (no Black (no Black (no Black (no
(no change) change) change) change) change) change) ZnSi.sub.6PP -
ZnSi.sub.7OHPP ZnSi.sub.8PP - H.sub.2TPP - H.sub.2FPP - Alizarin
basic - Black (no Black (no Black (no Black (no Black (no Green and
Purple change) change) change) change) change) Me Red - BCP - BCP
basic - BTB - BTB basic - Ph Red basic - Black (no Yellow White
Black (no Yellow Green change) change) Nile Red - BCG - Red BCG
basic - CresRed - CresRed CP Red - Green Black (no Red and Black
(no basic - Light change) Purple change) Green R Dye - TB - Black
TB basic - MeOr - MeOr basic - CP Red basic - Black (no (no change)
Black (no Blue Purple White change) change) (Analyte: Formic Acid
680 ppb) SnTPPCl.sub.2 - CoTPP - CrTPPCl - MnTPPCl FeTPPCl - CuTPP
- Black (no Black Black (no Black (no Black (no Black (no change)
(no change) change) change) change) change) AgTPP - NiTPP - InTPPCL
- IrTPPCl - ZnTPP - FeTFPPCl - Black Black (no Black (no Black (no
Black (no Black (no (no change) change) change) change) change)
change) ZnSi.sub.6PP - ZnSi.sub.7OHPP ZnSi.sub.8PP - H.sub.2TPP -
H.sub.2FPP - Alizarin basic - Black (no Black (no Black (no Black
(no Black (no Green and Purple change) change) change) change)
change) Me Red - BCP - BCP basic - BTB - BTB basic - Ph Red basic -
Black (no Yellow White Black (no Red Green change) change)
Periphery and Yellow Center Nile Red - BCG Red BCG CresRed -
CresRed CP Red - Black Black and Purple basic - Red Black (no basic
- Green (no change) (no and Purple change) change) R Dye - TB -
Black TB basic - MeOr - MeOr basic - CP Red basic - Black (no (no
change) Black (no Light blue Purple White change) change) (Analyte:
Acetic Acid 170 ppb) SnTPPCl.sub.2 - CoTPP - Black CrTPPCl -
MnTPPCl FeTPPCl - CuTPP - Black (no change) Black (no Black (no
Black (no Black (no (no change) change) change) change) change)
AgTPP - NiTPP - Black InTPPCL - IrTPPCl - ZnTPP - Black FeTFPPCl -
Black (no (no change) Black (no Black (no (no change) Black (no
change) change) change) change) ZnSi.sub.6PP - ZnSi.sub.7OHPP -
ZnSi.sub.8PP - H.sub.2TPP - H.sub.2FPP - Black Alizarin basic -
Black (no Black (no Black (no Black (no (no change) Black (no
change) change) change) change) change) Me Red - BCP - Red BCP
basic - BTB - BTB basic - Ph Red basic - Black (no Orange Black (no
Red Black (no change) change) change) Nile Red - BCG - Purple BCG
basic - CresRed - CresRed basic - CP Red. - Black (no and Orange
Purple Black (no Black (no Black (no change) Orange change) change)
change) R Dye - TB - Black (no TB basic - MeOr - MeOr basic - CP
Red Black (no change) Black (no Black (no Black (no basic - Black
change) change) change) change) (no change) (Analyte: Acetic Acid
250 ppb) SnTPPCl.sub.2 - CoTPP - CrTPPCl - MnTPPCl - FeTPPCl -
CuTPP - Black (no Black Black (no Black (no Black (no Black (no
change) (no change) change) change) change) change) AgTPP - NiTPP -
InTPPCL - IrTPPCl - ZnTPP - FeTFPPCl - Black Black (no Black (no
Black (no Black (no Black (no (no change) change) change) change)
change) change) ZnSi.sub.6PP - ZnSi.sub.7OHPP ZnSi.sub.8PP -
H.sub.2TPP - H.sub.2FPP - Alizarin basic - Black (no Black (no
Black (no Black (no Black (no Black (no change) change) change)
change) change) change) Me Red - BCP - BCP basic - BTB - BTB basic
- Ph Red basic - Black (no Yellow with Red Black (no Red Green
change) Red Center change) Nile Red - BCG - BCG basic - CresRed -
CresRed CP Red - Black Black (no Orange Red and Black (no basic -
(no change) change) Purple change) Black (no change) R Dye - TB -
Black TB basic - MeOr - MeOr basic - CP Red basic - Black (no (no
change) Black (no Black (no Black (no White change) change) change)
change) (Analyte: Acetic Acid 340 ppb) SnTPPCl.sub.2 - CoTPP -
CrTPPCl - MnTPPCl - FeTPPCl - CuTPP - Black (no Black Black (no
Black (no Black (no Black (no change) (no change) change) change)
change) change) AgTPP - NiTPP - InTPPCL - IrTPPCl - ZnTPP -
FeTFPPCl - Black Black (no Black (no Black (no Black (no Black (no
(no change) change) change) change) change) change) ZnSi.sub.6PP -
ZnSi.sub.7OHPP ZnSi.sub.8PP - H.sub.2TPP - H.sub.2FPP - Alizarin
basic - Black (no Black (no Black (no Black (no Black (no Black (no
change) change) change) change) change) change) Me Red - BCP - BCP
basic - BTB - BTB basic - Ph Red basic - Black (no Yellow Yellow
Black (no Ornage Green change) change) Nile Red - BCG - BCG basic -
CresRed - CresRed CP Red - Black Black (no Faint Purple Black (no
basic - (no change) change) Orange and change) Green Purple R Dye -
TB - Black TB basic - MeOr - MeOr basic - CP Red basic - Black (no
(no change) Black (no Black (no Black (no White change) change)
change) change) (Analyte: Acetic Acid 650 ppb) SnTPPCl .sub.2 -
CoTPP - CrTPPCl - MnTPPCl - n FeTPPCl - CuTPP - Black (no Black
Black (no Black (no Black (no Black (no change) (no change) change)
change) change) change) AgTPP - NiTPP - InTPPCL - IrTPPCl - ZnTPP -
FeTFPPCl - Black Black (no Black (no Black (no Black (no Black (no
(no change) change) change) change) change) change) ZnSi.sub.6PP -
ZnSi.sub.7OHPP ZnSi.sub.8PP - H.sub.2TPP - H.sub.2FPP - Alizarin
basic - Black (no Black (no Black (no Black (no Black (no Faint
Green change) change) change) change) change) Me Red - BCP - BCP
basic - BTB - BTB basic - Ph Red basic - Black (no Yellow and Faint
Orange Yellow Green change) Orange) Yellow Nile Red - BCG - BCG
basic - CresRed - CresRed CP Red - Faint Black (no Black (no Purple
Black (no basic - Green change) change) change) White R Dye - TB -
Black TB basic - MeOr - MeOr basic - CP Red basic - Black (no (no
change) Black (no Black (no Green White change) change) change)
(Analyte: Iso-Valeric Acid 280 ppb) SnTPPCl.sub.2 - CoTPP - CrTPPCl
- MnTPPCl - FeTPPCl - CuTPP - Black (no Black Black (no Black (no
Black (no Black (no change) (no change) change) change) change)
change) AgTPP - NiTPP - InTPPCL - IrTPPCl - ZnTPP - FeTFPPC - Black
Black (no Black (no Black (no Black (no Black (no (no change)
change) change) change) change) change) ZnSi.sub.6PP -
ZnSi.sub.7OHPP ZnSi.sub.8PP - H.sub.2TPP - H.sub.2FPP - Alizarin
basic - Black (no Black (no Black (no Black (no Black (no Black (no
change) change) change) change) change) change) Me Red - BCP - Red
BCP basic - BTB - BTB basic - Ph Red basic - Black (no Black (no
Faint Red Black (no Orange Orange change) change) change) Nile Red
- BCG - BCG basic - CresRed - CresRed CP Red - Black Black (no
Faint Purple Red Black (no basic - Dark (no change) change)
Periphery Periphery change) Green R Dye - TB - Red TB basic - MeOr
- MeOr basic - CP Red basic - Black (no and Purple Red Green Green
Green Periphery change) Periphery Periphery Center Periphery
(Analyte: Iso-Valeric 420 ppb) SnTPPCl.sub.2 - CoTPP - CrTPPCl -
MnTPPCl - FeTPPCl - CuTPP - Black (no Black Black (no Black (no
Black (no Black (no change) (no change) change) change) change)
change) AgTPP - NiTPP - InTPPCL - IrTPPCl - ZnTPP - FeTFPPCl -
Black Black (no Black (no Black (no Black (no Black (no (no change)
change) change) change) change) change) ZnSi.sub.6PP -
ZnSi.sub.7OHPP ZnSi.sub.8PP - H.sub.2TPP - H.sub.2FPP - Alizarin
basic - Black (no Black (no Black (no Black (no Black (no Black (no
change) change) change) change) change) change) Me Red - BCP - Red
BCP basic - BTB - BTB basic - Ph Red basic - Black (no Faint Black
(no Orange and Faint Orange and change) Green and change) Yellow
Green orange Nile Red - BCG - BCG basic - CresRed - CresRed CP Red
- Black Black (no Orange Orange Black (no basic - (no change)
change) Periphery change Green R Dye - TB - Black TB basic - MeOr -
MeOr basic - CP Red basic - Black (no (no change) Black (no Green
Green Green change) change) (Analyte: Iso-Valeric Acid 850 ppb)
SnTPPCl.sub.2 - CoTPP - CrTPPCl - MnTPPCl - FeTPPCl - CuTPP - Black
Faint Faint Purple Faint Faint Purple Faint Purple (no change) blue
Purple AgTPP - NiTPP - InTPPCL - IrTPPC1 - ZnTPP - FeTFPPCl - Black
Faint Blue Black (no Faint Pink Black (no Black (no (no change)
change) change) change) ZnSi.sub.6PP - ZnSi.sub.7OHPP ZnSi.sub.8PP
- H.sub.2TPP - H.sub.2FPP - Alizarin basic - Faint Blue Faint Blue
Black (no Faint Blue Black (no Black (no change) change) change) Me
Red - BCP - White BCP basic - BTB - Blue BTB basic - Ph Red basic -
Black (no and Red Yellow and Red Red and Yellow and Red change) and
Red Yellow Nile Red - BCG - White, BCG basic - CresRed - CresRed CP
Red - Faint Black (no Red and Blue White Purple basic - Orange
change) and Red Periphery Light Green R Dye - TB - Light TB basic -
MeOr - MeOr basic - CP Red basic - Faint Red Blue Purple Green and
Light Light Green Periphery Periphery Blue Green and Red Center
(Analyte: Iso-Valeric Acid 1700 ppb) SnTPPCl.sub.2 - CoTPP -
CrTPPCl - MnTPPCl - FeTPPCl - CuTPP - Black (no Black Black (no
Black (no Black (no Black (no change) (no change) change) change)
change) change) AgTPP - NiTPP - InTPPCL - IrTPPCl - ZnTPP -
FeTFPPCl - Black Black (no Black (no Black (no Black (no Black (no
(no change) change) change) change) change) change) ZnSi.sub.6PP -
ZnSi.sub.7OHPP ZnSi.sub.8PP - H.sub.2TPP - H.sub.2FPP - Alizarin
basic - Black (no Black (no Black (no Black (no Black (no Faint
Purple change) change) change) change) change) Me Red - BCP - Red
BCP basic - BTB - BTB basic - Ph Red basic - Black (no White Black
(no White White and Purple change) change) Nile Red - BCG - Red BCG
basic - CresRed - CresRed CP Red - Black Black and Purple White,
Black (no basic - (no change) (no Red, and change) White change)
Purple R Dye - TB - Black TB basic - MeOr - MeOr basic - CP Red
basic - Black (no (no change) Faint Red Black (no Faint Green
change) change) Green (Analyte: 3-Methyl-2-hexenoic Acid 12 ppb)
SnTPPCl.sub.2 - CoTPP - CrTPPCl - MnTPPCl - FeTPPCl - CuTPP - Black
(no Black Black (no Black (no Black (no Black (no change) (no
change) change) change) change) change) AgTPP - NiTPP - InTPPCL -
IrTPPCl - ZnTPP - FeTFPPCl - Black Black (no Black (no Black (no
Black (no Black (no (no change) change) change) change) change)
change) ZnSi.sub.6PP - ZnSi.sub.7OHPP ZnSi.sub.8PP - H.sub.2TPP -
H.sub.2FPP - Alizarin basic - Black (no Black (no Black (no Black
(no Black (no Black (no change) change) change) change) change)
change) Me Red - BCP - Faint BCP basic - BTB - BTB basic - Ph Red
basic - Black (no Purple White Black (no Red Purple and Green
change) and Purple change) Nile Red - BCG - BCG basic - CresRed -
CresRed CP Red - Black Black (no Faint Red Faint Black (no basic -
Light (no change) change) and Purple White and change) Blue and
Purple Green R Dye - TB - Black TB basic - MeOr - MeOr basic - CP
Red basic - Black (no (no change) Black (no Black (no Blue and
Green change) change) change) Green
[0343] FIG. 18 illustrates a preferred array containing
illustrative examples of porphyrin, metalloporphyrin, acid-base
indicator, and solvatochromatic dyes. Typical sizes of the array
can range from 0.5 mm to 2 cm on a side. Linear, hexagonal or
rectangular arrays are also easily used. From left to right and top
to bottom the identities and colors of the dyes used in the
illustrative example of FIG. 18 are listed in Table 13 as follows
(the exact colors depend, among other things, upon scanner
setting).
14TABLE 13 (Summarizing the Dyes and Colors in FIG. 18, i.e., "Dye
- Color") SnTPPCl.sub.2- CoTPP - Tan CrTPPCl - Green MnTPPCl -
FeTPPCl - Light CuTPP - Light Green with Dark Green Green Green
Light Pink Center Zn(C.sub.3F.sub.7).sub.4P - ZnF.sub.2PP - InTPPCl
- ZnTMP - ZnTPP - FeTFPPCl - Gray Light Pink Reddish Beige Pink
Salmon Beige ZnSi.sub.6PP - ZnSi.sub.7OHPP - ZnSi.sub.8PP - Light
H.sub.2TPP - H.sub.2FPP - Neutral Red Pink Pink Pink Light Greenish
Yellow Pink with Reddish Brown Beige Center Methyl Red - Disperse
Rosolic Acid - Fat Brown Cyanidin Metanil Orange Orange 25 - Red RR
- Dark Chloride - Yellow - Pinkish Reddish Brown Light Orange
Yellow Nile Red - Mordant 3,6-Acridineamine Bromocresol
Azodipyridine - Rosaniline - Yellow Light Purple Orange 1 - Yellow
Green - Pink Light Yellow Dark Yellow Reichardt's Acridine Crystal
Violet - Thymol Blue Congo Red - Malachite Dye - Teal Orange Dark
Blue Purple Dark Red Green Base - Carbinol Yellow base - Light Blue
Note: DOW CORNING 704 silicone diffusion pump fluid (Molecular
Weight: 484.82, Density: 1.070, CAS Number: 3982-82-9) was added to
all porphyrin solutions: 40 .mu.l/ml.
[0344] where
[0345] SnTPPCl.sub.2 is 5,10,15,20-Tetraphenyl-21H,23H-porphine
tin(IV) dichloride
[0346] Molecular Formula: C.sub.44H.sub.28SnCl.sub.2N.sub.4
[0347] Molecular Weight: 802
[0348] CAS: 26334-85-0;
[0349] CoTPP is 5,10,15,20-Tetraphenyl-21H,23H-porphine
cobalt(II)
[0350] Molecular Formula: C.sub.44H.sub.28CoN.sub.4
[0351] Molecular Weight: 671
[0352] CAS: 14172-90-8;
[0353] CrTPPCl is 5,10,15,20-Tetraphenyl-21H,23H-porphine
chromium(III) chloride
[0354] Molecular Formula: C.sub.44H.sub.28CrClN.sub.4
[0355] Molecular Weight: 700
[0356] CAS: 28110-70-5;
[0357] MnTPPCl is 5,10,15,20-Tetraphenyl-21H,23H-porphine
manganese(III) chloride
[0358] Molecular Formula: C.sub.44H.sub.28ClMnN.sub.4
[0359] Molecular Weight: 703
[0360] CAS: 32195-55-4;
[0361] FeTPPCl is 5,10,15,20-Tetraphenyl-21H,23H-porphine iron(III)
chloride
[0362] Molecular Formula: C.sub.44H.sub.28ClFeN.sub.4
[0363] Molecular Weight: 704
[0364] CAS: 16456-81-8;
[0365] CuTPP is 5,10,15,20-Tetraphenyl-21H,23H-porphine
copper(II)
[0366] Molecular Formula: C.sub.44H.sub.28CuN.sub.4
[0367] Molecular Weight: 676
[0368] CAS: 14172-91-9;
[0369] Zn(C.sub.3F.sub.7).sub.4P is meso
tetra(heptafluoropropyl)porphine zinc(II)
[0370] Molecular Formula: C.sub.32H.sub.8ZnF.sub.28N.sub.4
[0371] Molecular Weight: 1044;
[0372] ZnF.sub.2PP is
5,10,15,20-Tetrakis(2,6-difluorophenyl)-21H,23H-porp- hine
zinc(II)
[0373] Molecular Formula: C44H.sub.20F.sub.8N.sub.4Zn
[0374] Molecular Weight: 820;
[0375] InTPPCl is 5,10,15,20-Tetraphenyl-21H,23H-porphine
indium(III) chloride
[0376] Molecular Formula: C.sub.44H.sub.28ClInN.sub.4
[0377] Molecular Weight: 763;
[0378] ZnTMP is
5,10,15,20-Tetrakis(2,4,6-trimethylphenyl)-21H,23H-porphin- e
zinc(II)
[0379] Molecular Formula: C.sub.56H.sub.52N.sub.4Zn
[0380] Molecular Weight: 846
[0381] CAS: 104025-54-9;
[0382] ZnTPP is 5,10,15,20-Tetraphenyl-21H,23H-porphine
zinc(II)
[0383] Molecular Formula: C.sub.44H.sub.28N.sub.4Zn
[0384] Molecular Weight: 678
[0385] CAS: 14074-80-7;
[0386] FeTFPPCl is
5,10,15,20-Tetrakis(pentafluorophenyl)-21H,23H-porphine iron(III)
chloride
[0387] Molecular Formula: C.sub.44H.sub.8CIF.sub.20FeN.sub.4
[0388] Molecular Weight: 1063.85
[0389] CAS: 36965-71-6;
[0390] ZnSi.sub.6PP is 5(phenyl)-10,15,20-trikis(2
,6-disilyloxyphenyl)por- phyrinatozinc(II)
[0391] Molecular Formula:
ZnC.sub.80H.sub.112O.sub.6N.sub.4Si.sub.6
[0392] Molecular Weight: 1458;
[0393] ZnSi.sub.7OHPP is
5,10,15-trikis(2',6'-disilyloxyphenyl)-20-(2/-hyd-
roxy-6/-silyloxyphenyl)porphyrinatozinc(II)
[0394] Molecular Formula:
ZnC.sub.86H.sub.126O.sub.8N.sub.4Si.sub.7
[0395] Molecular Weight: 1604;
[0396] ZnSi.sub.8PP is
5,10,15,20-tetrakis(2/,6/-disilyloxyphenyl)porphyri-
natozinc(II)
[0397] Molecular Formula:
ZnC.sub.92H.sub.140O.sub.8N.sub.4Si.sub.8
[0398] Molecular Weight: 1718;
[0399] H.sub.2TPP is 5,10,15,20-Tetraphenyl-21H,23H-porphine
[0400] Molecular Formula: C.sub.44H.sub.30N.sub.4
[0401] Molecular Weight: 614.75
[0402] CAS: 917-23-7;
[0403] H.sub.2FPP is
5,10,15,20-Tetrakis(pentafluorophenyl)-21H,23H-porphi- ne
[0404] Molecular Formula: C.sub.44H.sub.10F.sub.2ON.sub.4
[0405] Molecular Weight: 974.57
[0406] CAS: 25440-14-6;
[0407] Azodipyridine is
6'-Butoxy-2,6-diamino-3,3'-azodipyridine
[0408] Molecular Formula: C.sub.14H.sub.18N.sub.6O
[0409] Molecular Weight: 286.34
[0410] CAS: 617-19-6;
[0411] Rosaniline is Para-Rosaniline Base
[0412] Molecular Formula: C.sub.19H.sub.19N.sub.3O
[0413] Molecular Weight: 305.4
[0414] CAS: 25620-78-4
[0415] FIG. 19 illustrates the response of the array described in
FIG. 18 to acetone. As shown in FIG. 18 and summarized in Table 14
below, the color changes of each dye in response to aceteone are as
follows (the exact colors depend, among other things, upon scanner
settings). The color changes are derived simply by comparing the
before exposure and after exposure colors and subtracting the two
images (i.e., the absolute value of the difference of the red
values becomes the new red value in the color difference map; etc.
for green values and blue values). If there is no change in the
red, green, and blue color values of a dye in the after-exposure
image, then the color difference map will show black (i.e., red
value =green value =blue value =0).
15TABLE 14 (Summarizing the Dyes and Colors in FIG. 19, i.e., "Dye
- Color") SnTPPCl.sub.2 - CoTPP - CrTPPCl - MnTPPCl FeTPPCl - CuTPP
- Black Reddish Lavender Gray Pink Black (no (no change) Brown
change) AgTPP - NiTPP - InTPPCL - IrTPPCl - ZnTPP - FeTFPPCl - Dark
White Light Teal Blue Light Black (no Dark Cobalt Green change)
ZnSi.sub.6PP - ZnSi.sub.7OHPP ZnSi.sub.8PP - H.sub.2TPP -
H.sub.2FPP - Alizarin basic - Black (no Aqua Dark Teal Green White
Dark Purple change) Periphery and Blue Center Me Red - BCP - BCP
basic - BTB - BTB basic - Ph Red basic - Dark Blue Green Light
Light Dark Blue Royal Blue Green Green Nile Red - BCG - Tan BCG
basic - CresRed - CresRed CP Red - Gold Olive Black (no Dark Pink
basic - Blue change) R Dye - TB - Brown TB basic - MeOr - MeOr
basic - CP Red basic - Light Green Light Dark Blue Black (no
change) Pink Green
[0416] Partial Oxidation
[0417] Having demonstrated electronic differentiation and
shape-selective distinction of analytes that bind to metal ions in
metallodyes and of acidic or basic analytes that effect other
chemoresponsive dyes (e.g., pH sensitive dyes and solvatochromic
dyes), there are further embodiments of the present invention that
provide for the differentiation of analytes that do not bind or
bind only weakly to metal ions. Such analytes include certain
organic compounds lacking ligatable functionality, such as simple
alkanes, arenes, alkenes and alkynes (especially if sterically
hindered), and molecules sterically hindered as to preclude
effective ligation.
[0418] By partially oxidizing (partial meaning oxidation that does
not convert all of the carbon atoms of the analytes completely to
carbon dioxide) such parent analytes, new mixtures of derivative
analytes are formed that provide a unique analytical fingerprint
for the presence of the parent analytes. The partial oxidation of
such parent analytes to mixtures of alcohols, aldehydes, ketones,
carboxylic acids, including small carboxylic acids (e.g., formic,
acetic, propionic), carbon monoxide, and carbon dioxide can be
easily accomplished, thus effecting the chemical conversion of
weakly-responsive organic compounds to more volatile organic
compounds. These more volatile organic compounds have a stronger
interaction(s) with the array of the present invention, and thus
provide stronger responses, than do the parent analytes with the
array of the present invention. Preferably, for example, after
partial oxidation of a parent analyte, the derivative analyte(s)
may have stronger ligation, acid-base (including Lewis and/or
Br?nsted acids and bases), hydrogen bonding, and/or dipolar
interactions with an array of the present invention than does the
parent analyte. For example, hexane can be partially oxidized to
derivative analytes such as hexanoic acid, hexanol, hexanal, and
C.sub.6-ketones.
[0419] Thus, a table or database of fingerprints of analytes can be
made in accordance with the present invention by subjecting known
analytes to partial oxidation pursuant to a certain protocol, and
then observing and recording the absorbance or reflectance response
an the above-described array to the partially oxidized known
analytes. Later, an unknown analyte can be subjected to the same
protocol of partial oxidation, and the resulting absorbance or
reflectance response or the array to the partially oxidized unknown
analyte can be matched with the corresponding fingerprint in the
table or database of fingerprints. For example, a known source of
hexane can be partially oxidized pursuant to a certain protocol,
and the fingerprint of the resulting analyte can be observed and
recorded. An unknown analyte can then be partially oxidized
pursuant to the same protocol, and if the fingerprint of the
resulting analyte matches that of hexane, then the unknown analyte
will have been identified as hexane.
[0420] In one embodiment, an above-described array is first
subjected to an unknown analyte that has not been partially
oxidized. Should the array have no response or a weak response to
the unknown analyte such that the unknown analyte cannot be
determined, then the unknown analyte can be subjected to a
particular partial oxidation protocol to form at least one
derivative analyte corresponding to the unknown analyte. The array
can then be subjected to the at least one derivative analyte and
inspected for a direct and distinct spectral absorbance or
reflectance response corresponding to the derivative analyte. The
response or fingerprint can then be matched with the corresponding
response or fingerprint of a known analyte that had been subjected
to the same particular partial oxidation protocol, and thus the
unknown analyte can be identified.
[0421] For partial oxidation of the parent analyte to occur, an
oxidizing source must react with the parent analyte. The oxidizing
source can be any suitable source of oxygen gas (e.g., as a
component of air), or other oxidant or oxidizing agent (e.g.,
hydrogen peroxide, hypochlorite, chlorine dioxide, chlorine or
other bleaching agents). To achieve partial oxidation of the parent
analyte, the oxidizing source must be present in a range of
concentration or amount sufficient to result in forming a
derivative analyte that has a stronger response with at least part
of the array of the present invention than the parent analyte, but
below that needed to fully oxidize the parent analyte completely to
carbon dioxide.
[0422] In one embodiment, the incoming gas to be analyzed is
brought into contact with an oxidizing source. For example, the
incoming gas having a parent analyte can be passed through a column
or cartridge comprising a heterogeneous oxidation catalyst. The
outgoing gas coming out of the column or cartridge will comprise at
least one derivative analyte that is then exposed to a dye array
previously described above. The time of transit (so-called
"residence time" of the analyte gas) over or through the bed of
oxidation catalyst can be adjusted by the flow rate or the physical
length of the catalyst bed so as to optimize the partial oxidation
of the parent analyte(s).
[0423] The extent of oxidation can also be adjusted by the
concentration of the oxidant in the analyte gas or liquid (e.g., by
adding O.sub.2 or hydrogen peroxide). Suitable oxidation catalysts
are of many potential types, including but not limited to noble
metals (e.g., Pt or Pd) or their oxides, early transition metal
oxides (e.g., V.sub.2O.sub.5), and metal-containing microporous
zeolites. Such oxidation catalysts can be used either in
substantially pure form or supported on various high surface area
supports, such as silica, alumina, charcoal, or diamtomaceous earth
among others.
[0424] If an oxidation catalyst is used, the extent of oxidation
can also be adjusted by the temperature at which the catalyst is
kept, such as a range that includes 100 K to 1000 K. An embodiment
may often utilize a catalyst of sufficient activity and
concentration to permit its effective use at room temperature.
[0425] FIG. 20 illustrates an embodiment of a vapor exposure
apparatus of the present invention. The basic difference between
the embodiment shown in FIG. 3B is that the embodiment shown in
FIG. 20 further includes a partial oxidation cartridge 200 having a
suitable oxidation catalyst 202. Partial oxidation of the incoming
gas or parent analyte 204 using oxidation catalyst 202 can be used
to provide increased sensitivities to analytes. More specifically,
the oxidation catalyst 202 of partial oxidation cartridge 200 can
used in accordance with the present invention to provide increased
sensitivities to analytes that do not have significant acidic or
basic functionality, including alkanes, arenes, alkenes and alkynes
(especially if sterically hindered), and molecules sterically
hindered as to preclude effective ligation.
[0426] FIG. 20 illustrates top and side views of bottom piece 21
and a top view of top piece 21' of a vapor exposure flow cell 20 of
the present invention. In the embodiment shown in FIG. 20, for
purposes of demonstration, a sensor plate 18 having array 16 is
placed inside of a flow cell 20 equipped with a quartz window 22.
In a preferred embodiment, flow cell 20 is made from stainless
steel. Inlet 23 for the analyte vapor includes partial oxidation
cartridge 200. Preferably, cartridge 200 is packed with a solid or
solid-supported oxidation catalyst 202 optimized for partial
oxidation of the incoming analyte. Cartridge 200 can be
thermostated above or below room temperature as needed to optimize
the partial oxidation of incoming analyte. Outlet 23' permits vapor
flow out from sensor plate 18. In accordance with this embodiment,
incoming gas or parent analyte 204 is partially oxidized as it is
passed through cartridge 200, and the partially oxidized gas 206,
which now contains at least one derivative analyte, flows into
contact array 16 of sensor plate 18, and then exits from outlet
23.'
[0427] In accordance with the present invention, a table of
responses of the array(s) described herein to a plurality of
distinct known analytes can be prepared and used identify an
unknown analytes at a later time.
[0428] The present invention provides methods for detection. In one
embodiment, a method (I) of detecting at least one parent analyte
comprises the steps of (a) forming an array by depositing at least
a first dye and a second dye directly onto a single support in a
predetermined patter combination, the combination of dyes in the
array having a distinct and direct spectral or reflectance response
to distinct analytes comprising one or more parent analytes or
their derivatives, (b) partially oxidizing at least one parent
analyte to form at least one derivative analyte corresponding to
said parent analyte, (c) subjecting the array to the at least one
derivative analyte, and (d) inspecting the first dye and the second
dye for a direct and distinct spectral response corresponding to
the derivative analyte.
[0429] In another embodiment, a method (II) of detecting at least
one unknown parent analyte comprises the steps of
[0430] (a) forming an array by depositing at least a first dye and
a second dye directly onto a single support in a predetermined
pattern combination, the combination of dyes in the array having a
distinct and direct spectral absorbance or reflectance response to
distinct analytes comprising one or more parent analytes or their
derivatives,
[0431] (b) partially oxidizing at least one known parent analyte
pursuant to a certain protocol to form at least one derivative
analyte corresponding to said known parent analyte,
[0432] (c) subjecting the array to the at least one derivative
analyte corresponding to said known parent analyte,
[0433] (d) inspecting the array for a direct and distinct spectral
response to the derivative analyte corresponding to said known
analyte,
[0434] (e) forming an array identical to the array formed in step
(a) by repeating step (a) or returning the array in step (a) to its
condition prior to step (c),
[0435] (f) partially oxidizing at least one unknown parent analyte
pursuant to the certain protocol to form at least one derivative
analyte corresponding to said unknown parent analyte,
[0436] (g) subjecting the array formed in step (e) to the at least
one derivative analyte corresponding to said unknown parent
analyte,
[0437] (h) inspecting the array after step (g) for a direct and
distinct spectral response to the derivative analyte corresponding
to said unknown parent analyte, and
[0438] (i) determining after step (h) whether the direct and
distinct spectral response of the array to the derivative analyte
corresponding to the unknown parent analyte matches the direct and
distinct spectral response of the array to the derivative analyte
corresponding to the known parent analyte in step (d).
[0439] The method (II) of the above paragraph can further comprise
the step of subjecting the array formed in step (e) to the at least
one unknown parent analyte prior to step (f) and determining
whether the array formed in step (e) has a response insufficient to
detect the unknown parent analyte prior to proceeding to step (f).
The method (II) can further comprise the step of subjecting the
array formed in step (a) to the at least one known parent analyte
prior to step (b) and determining whether the array formed in step
(a) has a response insufficient to detect the unknown parent
analyte prior to proceeding to step (b).
[0440] The present invention provides a method (III) of making a
table of responses of an array to a plurality of distinct analytes
comprising the steps of
[0441] (a) forming an array by depositing at least a first die and
a second dye directly onto a single support in a predetermined
pattern combination, the combination of dyes in the array having a
distinct and direct spectral absorbance or reflectance response to
distinct analytes comprising one or more parent analytes or their
derivatives,
[0442] (b) subjecting the array to at least one known parent
analyte,
[0443] (c) inspecting the distinct and direct absorbance or
reflectance response that exists of the array to the at least one
known parent analyte,
[0444] (d) if no distinct and direct absorbance or reflectance
response exists of the array to the at least one known parent
analyte, then partially oxidizing the at least one known parent
analyte pursuant to a certain protocol to form at least one
derivative analyte corresponding to said known parent analyte,
[0445] (e) subjecting the array to the at least one derivative
analyte corresponding to said known parent analyte,
[0446] (f) inspecting the array for a direct and distinct spectral
response to the derivative analyte corresponding to said known
analyte,
[0447] (g) forming an array identical to the array formed in step
(a) by repeating step (a) or returning the array in step (a) to its
condition prior to step (b),
[0448] (h) subjecting the array formed in step (g) to at least one
unknown parent analyte to determine whether the array has a
response sufficient to detect the unknown parent analyte,
[0449] (i) if after step (h) the array has a response sufficient to
detect the unknown parent analyte, then determining whether the
response matches the response of a known patent analyte in step
(c),
[0450] (j) if after step (h) the array does not have a response
sufficient to detect the unknown parent analyte, then partially
oxidizing the at least one unknown parent analyte pursuant to the
certain protocol to form at least one derivative analyte
corresponding to said unknown parent analyte,
[0451] (k) subjecting the array after step (j) to the at least one
derivative analyte corresponding to said unknown parent
analyte,
[0452] (l) inspecting the array after step (k) for a direct and
distinct spectral response corresponding to the derivative analyte
corresponding to said unknown parent analyte, and
[0453] (m) determining after step (l) whether the direct and
distinct spectral response of the array to the derivative analyte
corresponding to the unknown parent analyte matches the direct and
distinct spectral response of the array to the derivative analyte
corresponding to the known parent analyte in step (f).
[0454] Many modifications and variations may be made in the
techniques and structures described and illustrated herein without
departing from the spirit and scope of the present invention.
Accordingly, the techniques and structures described and
illustrated herein should be understood to be illustrative only and
not limiting upon the scope of the present invention.
* * * * *