U.S. patent application number 14/858609 was filed with the patent office on 2016-04-21 for device for multiple tests from a single sample.
The applicant listed for this patent is John W. Symonds, Mark Wells. Invention is credited to John W. Symonds, Mark Wells.
Application Number | 20160109359 14/858609 |
Document ID | / |
Family ID | 39762335 |
Filed Date | 2016-04-21 |
United States Patent
Application |
20160109359 |
Kind Code |
A1 |
Symonds; John W. ; et
al. |
April 21, 2016 |
DEVICE FOR MULTIPLE TESTS FROM A SINGLE SAMPLE
Abstract
A sample device and method for analyzing a sample are claimed.
The sample device is a flat disc containing channels and wells for
directing a sample to reagents located in the disc and for mixing
the sample with the reagents. The disc is mounted on an analyzer
and the sample is pumped into the disc, divided into a plurality of
sub-sample, and at least some of the sub-samples are mixed with a
number of reagents. The resultant analytes are analyzed
spectrophotometrically for a determination of the concentration of
various substances in the sample. The present invention permits
multiple tests to be performed quickly and automatically with
minimal operator involvement.
Inventors: |
Symonds; John W.;
(Huntsville, AL) ; Wells; Mark; (Athens,
AL) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Symonds; John W.
Wells; Mark |
Huntsville
Athens |
AL
AL |
US
US |
|
|
Family ID: |
39762335 |
Appl. No.: |
14/858609 |
Filed: |
September 18, 2015 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
12046792 |
Mar 12, 2008 |
9164111 |
|
|
14858609 |
|
|
|
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60906369 |
Mar 12, 2007 |
|
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Current U.S.
Class: |
436/79 ;
422/82.09; 436/123; 436/124; 436/125; 436/133; 436/165; 436/73;
436/80; 436/84; 436/94 |
Current CPC
Class: |
G01N 27/04 20130101;
G01N 2021/0328 20130101; G01N 33/1853 20130101; G01N 21/11
20130101; G01N 35/00069 20130101; G01N 1/38 20130101; G01N 33/18
20130101; G01N 1/2035 20130101; G01N 27/28 20130101; G01N 21/272
20130101; G01N 21/07 20130101; G01N 33/1813 20130101; G01N 1/18
20130101; G01N 21/253 20130101; G01N 33/182 20130101; G01N 2201/062
20130101; G01N 21/255 20130101 |
International
Class: |
G01N 21/27 20060101
G01N021/27; G01N 1/38 20060101 G01N001/38; G01N 21/25 20060101
G01N021/25; G01N 33/18 20060101 G01N033/18 |
Claims
1. (canceled)
2: A device for preparing a fluid sample for analysis comprising: a
body; an inlet port defined in the body for introducing the sample;
and a plurality of optical wells defined in the body for analyzing
the sample, wherein the optical wells are in fluid communication
with the inlet port
3: The device of claim 2 further comprising means for mixing a
reagent with the sample.
4: The device of claim 2 further comprising: a plurality of reagent
wells defined in the body; a plurality of reagent channels defined
in the body, wherein the reagent channels provide fluid
communication between the inlet port and the reagent wells; and a
plurality of optical channels defined in the body, wherein the
optical channels provide fluid communication between the regent
wells and the optical wells.
5: The device of claim 4 wherein the reagent wells are dimensioned
to contain a reagent, and the reagent wells and the optical
channels are dimensioned to utilize fluid flow for agitation to
assist in dissolving the reagent in the sample.
6: The device of claim 4 further comprising: a waste well defined
in the body; a plurality of waste channels defined in the body,
wherein the waste channels provide fluid communication between the
waste well and the optical channels.
7: The device of claim 2 wherein the body further comprises a
bottom plate and a lid, wherein a seal is formed between the lid
and the bottom plate.
8: The device of claim 2 further comprising an alignment notch
defined in the body and an outer edge of the body such that the
device can be consistently positioned in an analyzer based on the
body outer edge and the alignment notch.
9: The device of claim 2 further comprising an electrochemical
probe and sample device contact points, wherein the electrochemical
probe is received in a well selected from the group consisting of
the reagent well, the optical well, and the waste well, and the
sample device contact points are connected to the electrochemical
probe.
10: The device of claim 2 further comprising a source indicator
received on the body.
11: A device for preparing a fluid sample for analysis comprising:
a body; an inlet port defined in the body for introducing a fluid
sample; a plurality of reagent wells defined in the body; a
plurality of reagent channels defined in the body, wherein each
reagent channel connects one reagent well to the inlet port such
that samples flowing from the inlet port to the reagent well
provide agitation within the reagent well for dissolving a
reagent.
12: The device of claim 11 further comprising: a plurality of
optical wells defined in the body; and a plurality of optical
channels defined in the body, wherein the optical channels connect
the reagent wells to the optical wells.
13: The device of claim 11 wherein the body further comprises a lid
and a bottom plate, and the lid and bottom plate are sealed
together.
14: The device of claim 11 wherein the body is comprised of a
plastic material.
15: A method of analyzing a sample comprising: a) providing a
sample device having an inlet connected to a plurality of optical
wells; b) injecting the sample into the inlet such that the sample
flows through the sample device into the optical wells; and c)
analyzing the sample in the optical wells.
16: The method of claim 15 wherein step c) further comprises:
transmitting electromagnetic radiation in to the optical wells; and
measuring the amount of electromagnetic radiation emanating from
the optical wells.
17: The method of claim 16 wherein step c) further comprises:
placing the sample device in an analyzer; and rotating the sample
device at least one time, wherein the sample device is rotated
between at least two analyses stages.
18: The method of claim 15 wherein step a) further comprises:
injection molding a lid and a bottom plate, wherein the lid and the
bottom plate comprise a body of the sample device; and sealing the
lid and the bottom plate together.
19-21. (canceled)
Description
[0001] This application claims the benefit of U.S. Provisional
Application No. 60/906,369, filed Mar. 12, 2007.
BACKGROUND OF THE INVENTION
[0002] a. Field of the Invention
[0003] The present invention relates generally to the field of
chemical testing of a sample. More particularly, the invention
provides a system and method for rapid testing of water quality via
a small device that permits multiple tests to be performed
simultaneously and automatically from a single sample.
[0004] b. Description of the Related Art
[0005] The process of preparing water for consumption in this
country is highly regulated--nationally by the Environmental
Protection Agency, and locally by state environmental agencies.
Although the water treatment process is fairly straightforward,
documenting that all proper precautions have been taken to protect
the consumer can be a tedious and time-consuming process. In many
other countries, resources are not as readily available to test
water quality and, unfortunately, water is distributed for
consumption containing many dangerous mineral and biological
contaminants. The present invention is intended to simplify and
expedite the analytical aspect of water treatment.
Overview of the Water Treatment Process
[0006] Utilities may obtain water from rain water run-off collected
in rivers, lakes, and streams, or from wells. Fresh, untreated
water is referred to as "raw" water. The raw water is pumped to a
water treatment plant, where analytical tests are performed to
determine the quality of the raw ater. The water is then filtered
to remove debris and other turbid materials, and chemicals are
added to improve the quality of the water. The water is then
referred to as "finished" water. The finished water must be tested
and held to regulated standards before being released to the
distribution system. If the finished water passes all tests, it is
pumped to water tanks where it is held in waiting for the
consumer.
[0007] Almost all water systems currently employ at least one
operator who is responsible for laboratory procedures. Small labs
are kept in-house in order to maintain the water system in
compliance with certain mandatory tests that must be performed
frequently. In fact, many tests are required to be performed every
hour, a laborious and time-consuming undertaking.
[0008] The water quality tests generally consist of a
spectrophotometric analysis on 10-25 milliliter water samples of
both raw and finished water. The water samples are mixed with
chemical reagents and analyzed at a reagent-specific wavelength in
order to determine the concentration of certain components in the
water samples. Most analytes requires their own specific reagent
and each test must be run independently from the other tests. For
tests that are required frequently, this requires a series of
analyses to be performed hourly.
[0009] Although this manual method of testing is the standard
across the industry, it is not without problems. The series of
tests that must be performed is slow and tedious. Operators spend,
on average, approximately twenty minutes of each hour performing
simple analyses, and often more complex tests are left undone just
because there is not enough time or man-power to do them. In some
cases, multiple analytical devices must be purchased to increase
the testing capacity of the water system.
[0010] Sample size is an issue as well, not in that a water plant
cannot spare a few milliliters of water to run these tests, but
because the actual sample being analyzed is not truly indicative of
the entire water sample. A spectrophotometer works by shooting a
beam of electromagnetic radiation at a particular wavelength
through a sample and measuring the amount of electromagnetic
radiation absorbed by the sample. One form of electromagnetic
radiation is light, as from a light bulb. This beam of
electromagnetic is, at most, 10 millimeters in diameter. When
considering the size of a 25 milliliter sample vial, the test
actually sees less than 10% of the total sample volume. If the
sample is not 100% homogenous, the test results can be inaccurate.
By the reagent manufacturer's own standards, a 100% homogenous
mixture may not be achieved on most reagent-sample mixtures unless
constantly stirred for more than one hour, which is not practical
in this situation. Other tests which involve shooting a beam of
electromagnetic radiation at a particular wavelength through a
sample and measuring the amount of electromagnetic radiation coming
from the sample are also possible, such as fluorescence
testing.
[0011] Also, repetitive testing by humans is inefficient. Tedious
analytical tests such as these lead to increased user error and
careless mistakes. Many test operators are not trained as
laboratory technicians, but are expected to perform as such and are
held responsible for laboratory practices.
[0012] Unfortunately, the water treatment industry has been
underserved in the development of new technology to remedy these
problems. Prior art devices have been designed to perform automated
water quality testing, but the prior art devices require
sophisticated manufacturing techniques. It would be desirable to
have a system and method for rapid and repetitive testing of water
quality that permits simple and economical testing of water
samples.
SUMMARY OF THE INVENTION
[0013] The current invention is a sample device where one sample is
injected or input into the device one time, and a plurality of
different chemical analyses are independently performed on the
sample to provide several different test results. The sample is
split into a plurality of different sub-samples, where each
sub-sample is directed through a channel to an optical well.
Electromagnetic radiation is transmitted through the optical well,
and a detector detects how much electromagnetic radiation leaves
the optical well. Light is frequently the preferred type of
electromagnetic radiation used, and the amount of electromagnetic
radiation leaving the optical well indicates the amount of a
substance present in the sample. Before the sub-sample flows into
the optical well, it can be directed through a reagent well
containing a reagent specific to the chemical test to be performed.
The reagent is then dissolved, and can react with specific
compounds which may be in the sub-sample. The use of a specific
reagent is required for many of the tests performed, and the
reagent well and the channel between the reagent and optical well
aid in dissolving the reagent in the sample.
[0014] An analyzer is used in conjunction with the sample device to
perform the chemical tests. The sample device is aligned on the
analyzer, and different sources of electromagnetic radiation are
transmitted through the different optical wells. The analyzer can
be designed with fewer radiation sources than optical wells in the
sample device, so the sample device can be automatically rotated so
the radiation source is transmitted through a second optical well
after the first test is completed. This rotation and subsequent
testing can be repeated as often as desired, so if the sample
device had 16 optical wells, and the analyzer had 4 radiation
sources, there could be 4 consecutive tests performed.
[0015] In one embodiment, the sample device according to the
present invention will allow users to monitor the quality of a
water sample more quickly and more effectively than with
conventional methods. Current testing is very time consuming,
inefficient, and expensive. The sample device method will allow
multiple tests to be run simultaneously and data to be
automatically logged. Sample volumes will also be much reduced and
the training needs for laboratory personnel will be simplified. The
water system operator will simply have to load the water sample
onto the disc and place it in the analytical device. The unit can
be designed to automatically pump the water sample across several
reagents simultaneously, take spectrophotometric readings, and
generate a report showing the findings of each individual test.
[0016] One objective of the present invention to provide a low
cost, disposable device and analysis system to enable rapid and
automatic water quality testing.
[0017] Another objective of the present invention to provide for
automatic uploading of water quality testing data.
[0018] It is a further objective of the present invention to
improve the mixing of the water sample with reagents for a more
homogenized mixture when the sample is mixed.
[0019] Another objective is to provide a simple to operate system
for routine chemical analysis.
[0020] Yet another objective is to improve lab safety by minimizing
the number of operations and the amount and exposure to reagents
for the laboratory technician.
[0021] These and other objectives will be achieved by the device
described in more detail in the detailed description.
DESCRIPTION OF THE DRAWINGS
[0022] FIG. 1 is a top view of the sample device according to one
embodiment of the present invention.
[0023] FIG. 2 is a cross-sectional representation of the sample
device illustrated in FIG. 1, taken approximately along lines
2-2.
[0024] FIG. 3 is a cross-sectional representation of the sample
device mounted on the analyzer according to one embodiment of the
present invention.
[0025] FIG. 4 is a top view of a sample device mounted on the
analyzer, with the sample device shown in dotted lines.
[0026] FIG. 5 is a cross-sectional representation of a sample
device mounted on an analyzer according to another embodiment of
the present invention.
DETAILED DESCRIPTION
[0027] The present invention can be used for a wide variety of
sample testing applications, and this disclosure is not intended to
limit the invention to any one particular embodiment. One potential
use of the current invention is for the routine testing associated
with water treatment facilities, and the current discussion is
geared for this particular application. However, other possible
uses also exist, and this discussion is not intended to limit the
invention to this application. Those skilled in the art will
recognize there are other uses and/or applications of the current
invention which are intended to be included in this
description.
Sample Testing Background
[0028] The principles and method of operation of the water quality
analysis performed by the present invention are well known to
persons of skill in the art. The method works on principles of
light absorption; specifically, when an electromagnetic radiation
beam crosses a substance, some of the radiation is absorbed by
atoms, molecules or crystal lattices in the substance. Specific
chemical compounds absorb specific wavelengths of electromagnetic
radiation, so the concentration of these specific compounds can be
determined by measuring how much electromagnetic radiation of a
chosen specific wavelength is absorbed. Light is one form of
electromagnetic radiation, and is the radiation source referenced
in this discussion. Spectrophotometric chemical analysis can be
based on the creation of an absorbing compound from a specific
chemical reaction between a sample and a specific reagent. Beer's
law states that when an absorbing compound absorbs light of a
particular wavelength, the absorbance is directly proportional to
the concentration of the absorbing compound in solution, as long as
other factors are constant. The current system generally keeps the
other factors constant, so the absorbance is proportional to the
concentration of the absorbing compound.
[0029] The analysis of the sample is accomplished by first mixing
the sample with a reagent and then placing the mixed sample in
between a light source and a detector which can measure the amount
of light striking the detector. The amount of light passing through
the sample (i.e., the radiation that is not absorbed by the sample)
is detected by a detector or photometer which converts the light
energy into a voltage signal. The photometer sends the voltage
signal through an amplifier to a microprocessor which then
correlates the voltage signal with the concentration of the
absorbing atoms and molecules based upon the wavelengths which are
absorbed and the amount of light which is absorbed.
[0030] While the principles are well known in the art, the present
invention enables the user to perform multiple tests simultaneously
by providing a disposable sample device pre-loaded with multiple
reagents. For example, if the sample device includes 16 different
test sites, the following tests can be performed from a single
sample injected into a single sample device. These tests are
commonly required for water treatment facilities.
TABLE-US-00001 Total Iron CaCO.sub.3 Content (Hardness) Ferrous
Iron Carbon Dioxide Content Manganese Sodium Calcium Total Sulfates
Magnesium Aluminum Fluoride Silver Total Chlorine Color Free
Chlorine Turbidity
[0031] The sample device can be configured to support different
types of water sample tests that may be needed for different water
utilities. For example, a city using well water may need to perform
different tests than a city using river water. The reagents in the
sample device can be customized to support the type of water
utility that will be using the sample device. The sample device can
also be configured to support sampling applications other than
testing water for utilities.
[0032] Other tests which are more common in other industries
include fluorescence testing and electrochemical testing. In
fluorescence testing, one wavelength of electromagnetic radiation,
often in the ultraviolet frequency, is transmitted into the sample,
which absorbs energy from the radiation source. The sample material
then re-transmits a longer wavelength of electromagnetic radiation,
and the amount of the longer wavelength transmitted depends on the
concentration of a particular molecule in the sample.
[0033] In electrochemical testing, a probe is inserted into the
sample, and the voltage, current, and/or resistance transmitted by
the probe can be equated to a specific characteristic of the
sample. For example, with a pH probe, the voltage potential between
the probe and the hydrogen ions in the sample solution is measured,
and in a conductivity probe, the electrical resistance of the
sample solution is measured.
Sample Device
[0034] The present invention and its advantages are best understood
by referring to the drawings. The elements of the drawings are not
necessarily to scale, emphasis instead being placed upon clearly
illustrating the principles of the invention.
[0035] One embodiment of the present invention includes a sample
device 10 for preparing fluid samples as shown in FIGS. 1 and 2.
Reference to fluid samples is intended to include samples which are
fluids as well as samples typically considered to be solids, but
which are able to flow, such as sand. The sample device 10 is in
the shape of a disc with wells for introducing the sample to
various reagents, channels for mixing the sample with the reagents
and directing the sample flow, and wells for analyzing the sample.
The sample device 10 is also referred to as the disc 10 in this
description.
[0036] In this embodiment, the disc 10 is relatively thin and is
fabricated from a transparent material such as a plastic material.
The disc can also be fabricated from glass, quartz, or even
photopolymers used in stereo lithography such as
polydimethylsiloxane (PDMS.) The disc 10 has a body 12, including a
bottom plate 14 and a lid 16. The lid 16 is generally a solid flat
disc enclosing the top of the body 12. The lid 16 is permanently
affixed to the disc 10 by sonic welding, adhesive or other means
such that a seal is formed between the lid 16 and the bottom plate
14. A full surface bond between the lid 16 and the bottom plate 14
is desired. In one embodiment of the invention, the lid 16 is 1/16
inches thick, though other thicknesses are possible without
departing from the scope of the invention. Generally, the cavities
and paths defined in the body 12 are formed in the body bottom
plate 14, and the lid 16 is used to enclose and seal these paths
and cavities. There can be a base (not shown) affixed to the bottom
of the body bottom plate 14, either in place of the lid 16 or in
addition to the lid 16.
[0037] The disc 10 has in its center an inlet port 18 in the form
of a cylindrical through hole. Preferably, there is only one inlet
port 18 per disc 10. This inlet port 18 is defined in the body 12,
and passes into the body bottom plate 14. In this embodiment, the
sample enters the disc 10 through the inlet port 18 from a disc
bottom surface 20, though in other embodiments the sample is
introduced from a disc top surface 22. The inlet port 18 provides
access and fluid communication from outside of the disc 10 to an
inlet well 24 defined in the disc body 12. Once the sample is
introduced to the inlet well 24, it is divided into sub-samples.
The inlet well 24 can be concentric with the inlet port 18, and is
usually larger in diameter than the inlet port 18. In one
embodiment of the present invention, the inlet well 24 is 1/4
inches deep, though other dimensions are possible within the scope
of the invention.
[0038] There are several features defined within the disc body 12
below the top surface 22, and these features serve to contain,
direct and mix the sample during the sample testing process. A
plurality of channels 26 radiate from the inlet well 24. The
channels 26 include various channel sections, including a plurality
of reagent channels 28 which connects the inlet well 24 to a
plurality of reagent wells 30. The reagent channels 28 provide
fluid communication between the inlet port 18 and the reagent wells
30. The reagent wells 30 can be generally cylindrically shaped, and
are dimensioned with a sufficient depth to contain a reagent 32. A
plurality of reagents 32 can be pre-loaded into the reagent wells
30. As is known by persons of skill in the art, some reagents 32
are in solid tablet form. Other reagents 32 are typically in liquid
form, and may be loaded in the disc 10 in a semi-solid (e.g.,
"gel-cap") form.
[0039] For several tests, the reagents 32 need to be mixed and
dissolved in the sample before the sample is tested. Typically the
reagents 32 react with a particular component which may be in the
sample, and the compound resulting from the reaction absorbs the
light and is detected by the testing procedure. Therefore, the
reagent should be thoroughly mixed with the sample for the most
accurate test results. The reagent channel 28 can enter the reagent
well 30 at close to a tangent of the reagent well 30 to help
facilitate swirling and mixing within the reagent well. The
dimensioning of the reagent well 30 and reagent channel 28 to
facilitate swirling and agitation utilizes the fluid flow to aid in
dissolving the reagent 32 in the sample. The reagent channels 28
can be similar in depth to the reagent well 30 to facilitate
swirling and mixing in the reagent well 30 as the sample material
enters.
[0040] The channels 26 also include optical channels 34 which
connect and provide fluid communication between the reagent wells
30 with a plurality of optical wells 36. Preferably, the optical
channels 34 are shallow, and serve as mixing channels to further
mix the reagent 32 and the sample before the sample is
spectrophotometrically tested. The optical channels 34 are
dimensioned and sized so the fluid flowing through the channels 34
tends to agitate and mix the sample, and this enhances efficient
mixing of the reagents 32 with the samples. The optical channels 34
can be more shallow than the optical wells 36 or the reagent wells
30 to reduce the cross sectional area of the optical channels 34
and therefore increase the Reynolds number in the optical channels
34. This tends to enhance mixing by promoting turbulent flow in the
sample.
[0041] If a particular test or standard does not require a reagent
32, the inlet well 24 can be directly connected to the optical well
36 by the optical channel 34, with no reagent channel 28 or reagent
well 30 between the inlet well 24 and the optical well 36. As an
alternative, the disc 10 can be designed with the reagent channel
28 and reagent well 30 between the inlet well 24 and the optical
well 36, but the reagent well 30 can be left empty with no reagent
32. Either way, the sample can be directed to the optical well 36
without being mixed with a reagent 32, if desired.
[0042] Optical wells 36 can be generally cylindrical wells defined
in the body 12 to permit light to shine from beneath the disc 10
through the optical well 36 containing the sample to detectors
received above the optical wells 36, or vice versa. Therefore, the
optical well bottom surface 38 and the optical well top surface 40
should be transparent to the wavelength of light used, and the top
and bottom surfaces 38, 40 should be smooth to minimize diffraction
and scattering of the light signal. It is acceptable for the top
and bottom surfaces 38, 40 to absorb some of the light, as long as
enough light is allowed to pass for an accurate test of the sample
to be performed. In one embodiment of the invention, the reagent
wells 30 and optical wells 36 are 0.30 inches deep, though other
dimensions are possible.
[0043] Waste channels 42 are sized to permit excess sample to exit
the optical wells 36 and be received in an exterior waste well 44,
which can follow the perimeter of the disc 10. Therefore, the waste
channels 42 connect and provide fluid communication between the
optical wells 36 and the waste well 44. The waste well 44 is
sufficiently deep to contain excess water or sample material. The
waste channels 42, which are another part of the channels 26, can
narrow at their entrance to the waste well 44 in order to reduce
the possibility of backflow of sample material from the waste well
44 into the waste channels 42.
[0044] The lid 16 can include one or more vent holes 46, and the
vent hole 46 can be positioned over the waste well 44. The channels
26 include the reagent channel 28, the optical channel 34, and the
waste channel 42. These channels 26 provide fluid communication
between the inlet port 18, the inlet well 24, the reagent wells 30,
the optical wells 36, and the waste well 44, so a vent hole 46 in
fluid communication with the waste well 44 is also in fluid
communication with the other wells 24, 30, 36 and channels 26, 28,
34. Therefore, a vent hole 46 in fluid communication with the waste
well 44 allows for trapped gases and vapors to be vented throughout
the disc 10, and liquid flow is facilitated because the liquids are
not forcing gases into confined areas, which would develop a
resisting back pressure.
[0045] Although the illustrated embodiment is fabricated from a
transparent medium, in other embodiments the disc 10 could be
fabricated from a non-transparent medium, with the limitation that
the path light takes through the optical well 36 is relatively
transparent to the wavelength of light used. Generally, this means
the optical well bottom and top surfaces 38, 40 should be
relatively transparent to the wavelength of light used. The
material has to be transparent enough to the wavelength of light
used to allow for enough light to determine the concentration of
the compound being tested for. The intensity of the light source
can affect the degree of transparency required for the material
around the optical well 36.
[0046] The disc 10 can include a source indicator 48 received on
the body 12, such as a bar code. The source indicator 48 can be
received on any body surface, including the disc top or bottom
surface 20, 22 or a body outer edge 53. Positioning the source
indicator 48 on the disc top surface 22 may provide less resistance
to movement and/or abrasion or wear on the source indictor 48 than
either the bottom surface 20 or the body outer edge 53. The source
indicator can utilize a wide variety of indicators which can be
read, including variations in depth, magnetism, color, shape, size,
or position of marks. Any variation which can be read and
interpreted can be utilized to indicate source, and the source
indicator 48 can be used to indicate which type of tests are to be
performed with a particular sample device 10.
[0047] The disc 10 can also be used for electrochemical testing. An
electrochemical probe 47 can be positioned in an optical well 36, a
reagent well 30, or even the waste well 44, with sample device
contact points 49 connected to the electrochemical probe 47. When
the sample contacts the probe 47 received in the well 30, 36, 44,
the probe 47 interacts with the sample, and an electrical signal
indicates some characteristic of the sample material. A signal is
transmitted from the probe 47 to the sample device contact points
49, which can then be measured to calculate the sample
characteristic. The electrical signal can be a measurement of
voltage potential, resistance, or current, depending on the type of
electrochemical probe 47 utilized. For example, voltage potential
is measured when a pH probe is used, and resistance is measured
when a conductivity probe is used.
[0048] The disc 10 can be fabricated from a number of techniques,
such as injection molding, etching, or machining, and can be made
from a number of materials, such as acrylic, plastic, glass,
quartz, photopolymers, or composite materials. Injection molding of
the lid 16 and the bottom plate 14 allows rapid, affordable
production of the sample device body 12, and can include formation
of the source indicator 48. In one embodiment, the disc 10 is
approximately five (5) inches in diameter and approximately 3/8
inches thick, but other sizes are possible without departing from
the scope of the present invention.
The Analyzer and Testing
[0049] A functional representation of one embodiment of the disc 10
mounted on the analyzer 50 is shown in FIGS. 3 and 4. In this
embodiment, the disc 10 is mounted on the top of the analyzer 50
between rollers 52. The purpose of the rollers 52 is to constrain
and position the disc 10 while permitting it to rotate
horizontally. The sample device body outer edge 53 contacts the
rollers 52 such that the body outer edge 53 can rotate within the
rollers, but the basic position of the outer edge 53 is controlled
by the rollers 52. A rotation pin 54 in the analyzer 50 fits into
an alignment notch 56 defined in the disc body 12, and can be used
to rotate the disc 10 as needed between sample testings so
different sub-samples can be sequentially tested. The rotation pin
54 and alignment notch 56 also serve to properly and consistently
position and align the disc 10 on the analyzer 50, so the position
of each optical well 36 is set and known when an analysis is
started. To enable consistent and unique alignment of the disc 10,
the alignment notch 56 should be positioned somewhere other than
the center of the disc 10.
[0050] In the operation of the illustrated embodiment, the disc 10
is placed on the analyzer 50 and an opaque cover 58 is positioned
over the disc 10 such that the disc 10 is encased before a test is
started. The cover 58 is opened to insert or remove a sample device
10, and the cover 58 on the analyzer 50 is closed during the
testing to substantially block out ambient light from the sample
device 10. In this embodiment, the sample is injected into the
inlet port 18 from the disc bottom surface 20 and is directed via
sixteen (16) identical and equally-spaced channels 26 to sixteen
(16) optical wells 36. Air or another gas can be introduced into
the inlet port 18 after the sample, to move the sample through the
disc 10 and to maintain pressure on the sample material, thus
helping to keep the optical wells 36 full. The air pressure can be
maintained with a line using a valve (not shown) connected to the
inlet port 18. The sample could be injected through the same valve.
If the inlet port 18 is on the disc bottom surface 20, special
fittings can be used to seal the inlet port 18 to the analyzer
50.
[0051] After the sample is introduced into the optical wells 36, a
source 60 of electromagnetic radiation is activated to transmit
into the sample in the optical wells 36, and detectors 62 are
positioned to measure the amount of electromagnetic radiation
emanating from the optical wells 36. This is used to analyze the
samples in the optical wells 36. Generally, the detectors 62 are
positioned on the opposite side of the optical wells 36 from the
source 60. However, for fluorescence testing, the source 60 and the
detector 62 do not have to be aligned, so a wide variety of source
60 and detector 62 positions are possible. In this embodiment, LEDs
are used as the radiation source 60, and light is the radiation
emitted by the LED source 60, but lasers or other sources of
electromagnetic radiation could also be used.
[0052] Excess sample water drains into the waste well 44 via waste
channels 42. Excess air, forced out when the sample is introduced
into the disc 10, exits via the vent hole 46 in the lid 16. The
detectors 62 are connected to a microprocessor 66, which performs
the required calculations and records the test results. The term
"microprocessor" includes any device or collection of devices
capable of receiving signals and calculating concentrations or
other sample characteristics based on the signals received. A
greater concentration of the absorbing material in the optical well
36 results in more light from the LED source 60 being absorbed, and
less light reaching the detector 62. Therefore, after proper
calibration, the amount of light being detected by the detector can
be used to determine the concentration of the absorbing material in
the optical well 36. The disc 10 should be encased before the
testing operation, or ambient light will reach the detector 62 and
bias the test results.
[0053] The analyzer 50 can also perform electrochemical analysis if
properly configured. Analyzer contact points 68 can be provided on
the analyzer 50, with the analyzer contact points 68 positioned to
contact the sample device contact points 49 when the sample device
10 is properly positioned on the analyzer 50. The probe 47 in the
disc 10 then sends an electronic signal to be read by the
microprocessor 66 through the sample device contact points 49,
which are in electrical communication with the analyzer contact
points 68, which are connected to the microprocessor 66. The
analyzer and/or sample device contact points 49, 68 can be a
printed board or some sort, a contact pin, contact plates, or any
means of providing electrical communication when the analyzer and
sample device contact points 49, 68 are aligned. The analyzer 50
can provide an electrical signal to the probe 47 to produce the
probe signal, if necessary. It is also possible to include "+" and
"-" nodes in a well 30, 36, 44 in place of the probe 47, with the
analyzer providing charge to the nodes for other tests such as DNA
extraction.
[0054] The analyzer 50 can also be equipped with a device 70 for
reading the source indicator 48. This can be a bar code reading
device 70, but other devices can also be used depending on the type
of source indicator 48 used. For example, lasers for detecting
depth variation or lights and detectors for reading color
variations could be used.
[0055] The source indicator 48 could indicate which tests to
perform, and the disc 10 could be customized for that
pre-determined sample testing routine. The analyzer 50 could have a
plurality of sample testing routines, such as one for well water
supplies, one for river water supplies, and one for waste water
treatment. Such things as the number of sub samples generated, the
reagents 32 used, the position of the optical wells 36, and probe
47 positions could be customized for each test routine, and the
source indicator 48 allows the analyzer 50 to select the proper
testing routine.
[0056] In one embodiment of the invention, the analyzer 50 provides
four (4) equally-spaced LED source's 60 and four (4) equally-spaced
detectors 62 which are used to test sixteen (16) analytes in the
sixteen (16) optical wells 36. Each LED source 60 can be at a
specific wavelength of light, so the reagents and tests would be
grouped based on the required wavelength for the test. With this
configuration, the analytes in four (4) optical wells 36 may be
analyzed simultaneously. After analysis of four analytes, the
analyzer 50 rotates the sample device 10 until the four (4) LED
sources 60 underlie four different optical wells 36, and the next
four analytes are tested. This process is repeated until all
sixteen (16) analytes have been tested.
[0057] It may be desirable to leave at least one reagent well 30
empty, and use the associated optical well 36 as a blank for a
baseline reading. This baseline can then be applied to other
samples tested. The rotation is driven in the illustrated
embodiment by the rotation pin 54 on the analyzer 50 that engages
in the notch 56 in the disc bottom surface 20. The disc 10 is held
in position during the rotation by the rollers 52, so the disc 10
rotates about its center axis. The rotation pin 54 allows the
sample device 10 to be rotated between at least two analysis
stages, which can be different tests or redundant tests, as
desired.
[0058] Another embodiment of the present invention is illustrated
in FIG. 5. In this embodiment, the inlet port 18 is on the disc top
surface 22, and there is no central hole through the disc bottom
surface 20. The cover 58 of the analyzer 50 includes a seal 64 that
seals against the disc 10 when the cover 58 is closed. Using this
embodiment, the sample can be introduced into the disc 10 before
the disc 10 is mounted on the analyzer 50, or the sample can be
introduced into the disc 10 after the disc 10 is mounted on the
analyzer 50 with the cover 58 closed. This seal 64 may be
accomplished by any number of methods well known by persons of
skill in the art. The seal 64 should block light which can
interfere with the optical testing, and the seal may be water-proof
to minimize issues associated with leaks.
[0059] The disc 10 and analyzer 50 in the illustrated embodiment
include sixteen reagent wells 30 and sixteen optical wells 36, and
permit four tests to be performed at once. This configuration was
chosen in order to permit multiple tests to be performed quickly
while keeping the size of the analyzer 50 reasonably small, e.g.,
smaller than a breadbox. However, other configurations are possible
without departing from the scope of the present invention. By way
of example only, the analyzer 50 could be enlarged to perform
sixteen tests at one time, and thus the rotation of the disc 10
would not be necessary. Further, the size of the disc 10 and the
number of optical wells 36 could be varied. Thus, a wide variety of
disc 10 and analyzer 50 configurations are possible, depending upon
the number and nature of the tests desired to be performed and the
size and space limitations of the analyzer 50.
[0060] In addition, although the illustrated embodiment of the disc
10 is generally symmetrical, some tests may require a different
topography of channels 26 and wells 28, 34, 44. Therefore other
configurations and sizes of channels 26 and wells 28, 34, 44 are
possible within the scope of the present invention.
[0061] While the invention has been described with respect to a
limited number of embodiments, those skilled in the art, having the
benefit of this disclosure, will appreciate that other embodiments
can be devised which do not depart from the scope of the invention
as disclosed here. Accordingly, the scope of the invention should
be limited only by the attached claims.
* * * * *