U.S. patent number 3,899,296 [Application Number 05/489,305] was granted by the patent office on 1975-08-12 for whole blood analysis rotor for a multistation dynamic photometer.
This patent grant is currently assigned to The United States of America as represented by the United States Energy. Invention is credited to Wayne F. Johnson, James C. Mailen.
United States Patent |
3,899,296 |
Mailen , et al. |
August 12, 1975 |
Whole blood analysis rotor for a multistation dynamic
photometer
Abstract
A rotor for performing photometric analyses using whole blood
samples. Following static loading of a gross blood sample in the
rotor the red blood cells in the gross sample are centrifugally
separated from the plasma and measured subvolumes of plasma
distributed to respective sample analysis cuvettes positioned in an
annular array about the rotor periphery. Means for adding reagents
to the respective cuvettes are also described.
Inventors: |
Mailen; James C. (Oak Ridge,
TN), Johnson; Wayne F. (Loudon, TN) |
Assignee: |
The United States of America as
represented by the United States Energy (Washington,
DC)
|
Family
ID: |
23943286 |
Appl.
No.: |
05/489,305 |
Filed: |
July 17, 1974 |
Current U.S.
Class: |
422/50; 356/39;
422/72; 494/10; 494/17 |
Current CPC
Class: |
G01N
21/07 (20130101); B01L 3/502738 (20130101); B01L
2400/0409 (20130101); B01L 2400/0633 (20130101); B01L
2400/043 (20130101); B01L 2400/0616 (20130101) |
Current International
Class: |
G01N
21/03 (20060101); G01N 21/07 (20060101); B04B
005/12 (); G01N 033/16 (); G01N 021/00 (); G01N
001/10 () |
Field of
Search: |
;23/253R,259
;356/39,197,246 ;233/26 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Wolk; Morris O.
Assistant Examiner: Hagan; Timothy W.
Attorney, Agent or Firm: Carlson; Dean E. Zachry; David S.
Hamel; Stephen D.
Government Interests
BACKGROUND OF THE INVENTION
The invention described herein relates generally to photometers and
more particularly to an improved whole blood analysis rotor for a
multistation dynamic photometer of the rotary cuvette type. It was
made in the course of, or under, a contract with the U.S. Atomic
Energy Commission.
Claims
What is claimed is:
1. An improved rotor for a photometric solution analyzer of the
rotary cuvette type suitable for use in analyzing whole blood
samples comprising a generally disk-shaped member defining:
a. a plurality of sample analysis cuvettes disposed in a circular
array for receiving liquid samples and reagents, said disk-shaped
member having transparent walls adjacent said sample analysis
cuvettes for permitting the passageway of light therethrough;
b. a centrally located static loading chamber having a loading port
for receiving gross whole blood samples;
c. a central fluid transfer cavity in open communication with the
outside of said disk-shaped member;
d. a continuous annulus positioned on a radius intermediate said
cuvettes and said static loading chamber;
e. at least one first passageway communicating between said annulus
and said static loading chamber;
f. at least one overflow chamber positioned intermediate said
annulus and said static loading chamber;
g. at least one second passageway communicating between said
annulus and said at least one overflow chamber;
h. a plurality of third passageways each of which is radially
folded to form three radially extending interconnected passageway
segments; a first segment extending radially from a respective
sample analysis cuvette to a point centripetal to said overflow
chamber, a second segment extending from the centripetal end of
said first segment to a radius about equal to that of said annulus,
and a third segment extending from the centrifugal end of said
second segment to said central fluid transfer cavity;
i. a plurality of connecting passageways extending between said
annulus and the centrifugal ends of respective second and third
segments of said third passageways;
j. a magnetically actuated ball trap valve disposed in each of said
connecting passageways; and
k. means for injecting reagents into said sample analysis
cuvettes.
2. The improved rotor of claim 1 wherein said annulus and said
first, second, third and connecting passageways are capillary
sized.
3. The improved rotor of claim 1 wherein said second and third
segments of said third passageways define a preselected sample
volume.
4. The improved rotor of claim 1 wherein said magnetically actuated
ball trap valve includes a radially oriented ball traverse chamber
and a ball of magnetic material disposed within said ball traverse
chamber; the centrifugal end of each of said ball traverse chamber
being in communication with a respective connecting passageway.
5. The improved rotor of claim 1 wherein said means for injecting
reagents into said sample analysis cuvettes includes a static
reagent loading chamber disposed centripetally to each cuvette, and
a radially-extending reagent transfer passageway communicating
between the centrifugal end of each reagent loading chamber and a
respective cuvette.
Description
Fast photometric analyzers incorporating multistation rotary
cuvette systems are becoming widely used in various laboratories
because of their ability to rapidly and accurately analyze large
numbers of samples. Of particular interest are blood tests
including glucose, LDH, SGOT, SGPT, BUN, total protein, alkaline
phosphatse, bilirubin, calcium, chloride, sodium, potassium and
magnesium. Since such tests are normally performed on blood plasma,
blood cells must be removed from whole blood samples prior to
analysis. Cuvette rotors designed to accept and automatically
process whole blood samples must, therefore, be capable of
separating plasma from cellular material. In addition, such rotors
must be designed for receiving a sample in a loading operation,
measuring discrete subvolumes of separated plasma for each sample
analysis cuvette and transferring the subvolumes into the
respective cuvettes.
It is, accordingly, a general object of the invention to provide an
improved rotor for a multistation photometric analyzer which is
suitable for use in performing whole blood analyses.
Another more particular object of the invention is to provide an
improved rotor for a multistation photometric analyzer suitable for
receiving a whole blood sample, centrifuging the whole blood sample
to separate its plasma and cellular components, measuring discrete
plasma subvolumes and transferring the subvolumes to respective
sample analysis cuvettes.
Other objects of the invention will be apparent from an examination
of the following written description of the invention and the
appended drawings.
SUMMARY OF THE INVENTION
In accordance with the invention, an improved rotor for a
multistation photometric analyzer is provided which is suitable for
use in performing whole blood analyses. The rotor is a generally
disk-shaped body defining: a circular array of peripherally-located
sample analysis cuvettes; a centrally located static loading
chamber having a central loading port for receiving gross whole
blood samples; a continuous capillary-sized annulus positioned on a
radius intermediate said cuvette and said static loading chamber;
at least one first capillary-sized passageway communicating between
said static loading chamber and said annulus; at least one second
capillary-sized passageway communicating between said annulus and a
centrifugal overflow chamber positioned centripetal to said
annulus; third capillary-sized passageways radially folded to form
three radially-extending interconnected passageway segments, a
first segment extending radially from each cuvette to a point
centripetal to said overflow chamber, a second segment extending
from the centripetal end of the first segment to a radius about
equal to that of the annulus and a third segment extending from the
centrifugal end of the second segment to a central fluid transfer
cavity in open communication with the central loading port; and
valve containing connecting passageways extending between the
annulus and the centrifugal ends of the second and third segments
of the third capillary-sized passageways. Rotors made according to
the invention accept whole blood samples, separate plasma from
cellular material, measure subvolumes of the separated plasma, and
transfer the measured subvolumes to respective sample analysis
cuvettes where they are mixed with suitable reagents and
photometrically analyzed.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a bottom plan view of a rotor made in accordance with the
invention.
FIG. 2 is a vertical sectional view taken along line 2--2 of FIG.
1.
FIG. 3 is a top plan view of the rotor of FIG. 1.
FIG. 4 is a vertical sectional view taken along line 4--4 of FIG.
3.
DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring now to the drawings, initially to FIGS. 1 and 2, the
bottom side and a first sectional view of a disk-shaped rotor 2 are
shown, respectively. In construction, the rotor is of laminated
design with a central, preferably opaque, plastic disk 3 sandwiched
between top and bottom transparent disks 4 and 5. A circular array
(only three shown) of axially extending apertures are provided
through disk 3 to serve as sample analysis cuvettes 6. As shown,
the bottom side of disk 3 is provided with a central circular
static loading chamber 7 which communicates via a plurality of
first radially extending capillary-sized flow passageways 8 with a
continuous capillary-sized annulus 9. Capillary-sized passageways,
although not essential to the operation of the invention, are used
to reduce the total blood sample volume requirement of the rotor.
Larger passageways may be used in rotors designed to test samples,
such as sewage effluents, which are not subject to the volumetric
restrictions of blood samples. An axially extending loading port 11
provides access to loading chamber 7 through the top of the rotor.
Also shown in FIG. 1 are second radially extending capillary-sized
passageways 12 communicating between annulus 9 and respective
overflow chambers 13 designed to limit the centripetal displacement
of blood within passageways described in later reference to FIGS. 3
and 4.
Turning now to FIGS. 3 and 4 wherein the top side and a second
sectional view of the rotor of FIG. 1 are shown, a third
capillary-sized passageway 14 is radially folded to form three
radially-extending interconnected passageway segments. A first
segment designated 14a extends radially from each cuvette to a
point centripetal to overflow chambers 13. A second segment
designated 14b extends from the centripetal end of the first
segment to a radius roughly corresponding to that of annulus 9. The
third segment designated 14c extends from the centrifugal end of
the second segment to a central fluid transfer cavity 15 in open
communication with central loading port 11 and the top surface of
top transparent disk 4.
As shown in FIGS. 1, 3 and 4, annulus 9 communicates with
passageways 14 by means of valve containing connecting passageways
17 extending between the annulus and the centrifugal ends of
passageway segments 14b and 14c. A magnetically opened ball check
valve includes a ball traverse chamber 18 of larger diameter than
the capillary-sized passageways 14 and 17 to permit ball 19 to
close off passage of liquid between the annulus and passageway 14
during centrifugation, except when an axially located magnet 21
(shown schematically) is brought into position or activated to hold
the valve open by drawing ball 19 (of magnetic material) to the
centripetal ends of ball traverse chamber 18. Chamber 18 extends
radially so that rotation-induced inertial forces press ball 19
against the opening of passageway 17 at the centrifugal end of that
chamber.
Also shown in FIG. 3 is a reagent loading chamber 22 which may be
statically loaded through loading port 23. A reagent transfer
passageway 24 extends radially between each chamber 22 and a
respective cuvette 6 to permit rotation-induced transfer of reagent
from the chamber to a respective cuvette where it mixes with blood
plasma and is photometrically analyzed.
OPERATION
In operation, a rotor as hereinbefore described is placed in a
turntable such as that shown in U.S. Pat. No. 3,798,459 which
issued Mar. 19, 1974, in the name of Anderson et al. A gross whole
blood sample is loaded, preferably by a hypodermic needle extending
through loading port 11 into loading chamber 7 while the rotor is
at rest. Suitable reagents are likewise loaded into loading
chambers 22 through loading ports 23. Although not shown in FIG. 3,
one complete set of loading chamber 22, passageways 14 and 17,
etc., is provided for each sample analysis cuvette 6. Only one set
of those features is illustrated to simplify the drawing without
detracting from a full understanding of the invention.
Once static loading of the whole blood sample and reagents has been
completed, the rotor is accelerated to a low speed, typically 300
to 500 rpm, and magnet 21 activated to open the ball check valves
by drawing check balls 19 to the centripetal ends of the respective
ball traverse chambers 18. Reagents contained in loading chambers
22 pass immediately through passageways 24 to respective sample
analysis chambers 6 under the influence of rotation-induced
inertial forces. During this initial low speed rotation, the whole
blood sample in loading chamber 7 flows outward through passageways
8 into annulus 9 from which it flows radially inwardly into
passageways 12, 17 and segments 14b and 14c of passageways 14 to a
common radius as determined by radius R where overflow occurs into
overflow chambers 13. The gross volume of the statically loaded
whole blood sample is selected to cause overflow into chambers 13
without filling those chambers. As indicated above, the common
centripetal end of interconnected passageway segments 14a and 14b
is centripetal to the radius R defining the overflow level so that
no blood spills into the sample analysis cuvettes during this
initial low speed centrifugation step.
Following the initial low speed centrifugation step wherein whole
blood is caused to rise within passageway segments 14b and 14c to a
level corresponding to radius R, magnet 21 is removed or
de-energized and rotational speed increased to about 4000 rpm. Ball
check 19 moves to the centrifugal end of ball traverse chamber 18
where it blocks passageway 17 as shown in FIG. 4. High speed
centrifugation is continued until all red blood cells within
passageway segments 14b and 14c sediment into chamber 18 which is
sized to hold all the red blood cells in a normal blood sample
contained within passageway segments 14b and 14c. The plasma-red
cell interface following sedimentation of the red cells will thus
normally be within ball transfer chamber 18 leaving passageway
segments 14b and 14c containing a measured volume of plasma only.
The plasma volume is determined by the length and cross section of
segments 14b and 14c and the selection of radius R which limits the
centripetal level to which the segments are filled.
The volume of clarified plasma contained in passageway segments 14b
and 14c is transferred to a respective sample analysis cuvette 6
with the rotor spinning at reduced speed, typically about 1000 rpm,
by applying a slight positive air pressure to the central opening
in disk 4 to pressurize fluid transfer cavity 15. This slight
pressure forces the plasma to flow from passageway segments 14b and
14c through segment 14a and into a sample analysis cuvette where it
mixes with reagent previously transferred to the cuvette upon
initial rotation. Alternatively, a rinse solution of distilled
water could be injected into fluid transfer cavity 15 to displace
plasma from passageway segments 14b and 14c. Photometric analysis
of the cuvette contents is then made while the rotor continues to
rotate at about 1000 rpm in accordance with the techniques and
principles taught in U.S. Pat. No. 3,555,284 issued Jan. 12, 1971,
in the name of Norman G. Anderson.
The above described preferred embodiment and method of operation
are intended to be illustrative only and should not be interpreted
in a limiting sense. For example, particulate suspensions other
than whole blood could be processed to remove particulates and the
clarified supernatant analyzed. It is intended rather, that the
invention be limited in scope only by the following claims.
* * * * *