US 3681029 A
Description (OCR text may contain errors)
Aug. 1, 1972 5. SHAPIRO 3,681,029
' SAMPLE HOLDER AND TRANSFERRING DEVICE FOR A CENTRIFUGE Filed April L5. 1970 INVENTORS STEPHEN SHAP/RO AIH HNI Y United States Patent 01 fice 3,681,029 Patented Aug. 1, 1972 ABSTRACT OF THE DISCLOSURE Known rotary photometric analyzers have a series of cuvettes arranged vertically and concentrically around a horizontally rotatable disk so that when the disk is rotated centrifugal force mixes and transfers reagents and samples to the cuvettes. As each cuvette passes a light source the samples are analyzed photometrically by pro jecting a light beam through the bottom'of the cuvette and measuring the absorbence as the beam emerges from the top of the cuvette. In the improvement of this invention the analyzer is provided with a sample holder and transferring device having reagent, sample and transfer chambers disposed in such a geometric configuration that the entire sample is picked up in the reagent and swept into the cuvette.
This invention relates to a novel sample holder and transferring device. In one aspect, this invention relates to an apparatus for transferring reagents and samples. In a further aspect, this invention relates to a device for dispensing measured volumes of liquids for microanalytical photometric systems.
In recent years the need for rapid, automatic, analytical devices has increased markedly due to the numerous microanalytical studies in biochemical research, routine clinical testing for physicians and hospitals, enzymatic studies and the like. In addition to the increased demand for analyses, in certain fields it is often critical that a series of reactions be started at exactly the same time if reliable results are to be obtained. This is particularly important for enzymatic studies wherein detectable changes often take place after the reaction has proceeded for only a few seconds or minutes. However, few devices are avaiable which can analyze rapidly and accurately to handle the increasing number and varied test desired by clinicians and research workers.
Recently, multistation analytical lphotometers which utilize a centrifugal field have become available for the rapid microanalysis of a wide variety of liquids such as body fluids, e.g., blood serum, feed products, and the like. Since numerous analyses can be performed rapidly and simultaneously these devices are of particular interest wherein a large number of samples is involved or a variety of tests on one sample is desired. Moreover, since these devices allow the use of relatively small volumes of reagents, i.e., in the microliter range, the use of expensive reagents can be minimized.
One such device which utilizes a centrifugal field in microanalytical studies is described in Analytical Biochemistry 28,545-562 (1969). This device employs the principle of double-beam spectrophotometry wherein absorbencies of a liquid sample and a reference solution are intercompared. The system is basically a series of cuvettes arranged around the periphery of a rotor so that when it is spun, centrifugal force transfers reagents and samples to the cuvettes where the concentration is measured spectrophotometrically. A sample loading disk is provided which consists of rows of cavities arranged concentrically. Reagents are placed in the inner-most cavity and serum samples in the center cavity of the sample loading disk which is then indexed and positioned in the rotor with each reagent and serum sample having its respective cuvette. As the rotor is accelerated, centrifugal force moves the reagents and sample to the outer-most cavity where they are transferred through a small channel to the cuvette. During the transfer, the reagent and sample mix. The filled cuvettes rapidly spin past the fixed light beam and the transmission of light is measured.
However, the geometery of the cavities in the rotary must be such that the reagents and sample are completely transferred into the cuvette. If transfer is not complete, the cuvette may contain an improper concentration of sample and hence give an erroneous reading. In view of the fact that the instrument is particularly useful for bio chemical clinical testing, it is imperative that accuracy be at its optimum.
It is therefore an object of this invention to provide an improved sample holder and transferring device for use in rotary photometric analyzers. A further objetc of this invention is to provide an improved sample holder and transferring device wherein the sample and reagents are completely transferred to the cuvette. These and other objects will readily become apparent to those skilled in the art in the light of the teaching herein set forth.
In its broad aspect, the invention relates to an improved sample holder and transferring device adaptable for use in rotary photometric analyzers. The device is comprised of, in combination, an annular disk having on its upper surface a pluralityof chambers each of which extends outwardly toward the peripheral edge of the disk. The chamber is comprised of at least one reagent chamber disposed at an angle which is less than a right angle to the direction of the force created by the centrifugal field. a sample chamber communicating with the adjacent to the reaction chamber the depth of which is less than the reagent chamber, and a transfer chamber communicating with and adjacent to the sample chamber and disposed at an angle greater than a right angle to the direction of the force created by the centrifugal field. The transfer chamber communicates to the outer peripheral edge of the disk through an exit port. When the rotor is in place in the analyzer, the exit ports communicate with the cuvettes.
With reference to the drawing, there is depicted a cross-sectional view of the rotor disk 10 which rotates about axis 12 and which contains reagent chamber 14,
sample chamber 16, transfer chamber 18 and exit port 20. As is evident from the drawing, when the disk containing reagent and sample commences to rotate, the increasing centrifugal force drives the reagent from its chamber up to the shelf formed by the reagent and sample chambers and sweeps the sample from its chamber over into the transfer chamber. Mixing of reagent and sample begins immediately as the reagent sweeps the sample into the transfer chamber and eventually into the cuvette.
Due to the fact that the reagent and sample chambers are inclined towards the outer peripheral edge of the disk and the sample chamber is not as deep as the reagent chamber, i.e., it forms a shelf with the reagent chamber, the reagent and sample are kept separated until the rotor disk revolves. The liquid reagent then rises up its outer wall and passes over the bottom of the sample chamber and sweeps the sample up the sample chamber wall and into the transfer chamber. The sample chamber wall should rise to a point just below the upper surface of the rotor disk.
In practice, the chambers can be of a variety of configurations. For example, they can be cylindrical, oval, square, or the like, as long as the basic geometric configuration is maintained. The rotor disk itself can be constructed out of a variety of materials such as high density linear polyethylene, tetrafluoroethylene, and the 3 like. The surface of the chambers must, of course, be of such material that neither reagents of samples will adhere strongly to it when the rotor is revolving.
Although the invention has been illustrated by the preceding disclosure, it is not to be construed as being limited to the particular embodiments or materials disclosed therein. Rather, the invention encompasses the generic area as hereinbefore disclosed. Various modifications and embodiments thereof can be made without departing from the spirit and scope thereof.
The device of this invention is employed in conjunction with the instrument described in the foregoing Analytical Biochemistry Journal.
What is claimed is:
1. A sample holder and transferring device for use in mixing and transferring liquids in a centrifugal field, said device comprised of, in combination an annular disk having on its upper surface a plurality of chambers each of which extends outwardly toward the peripheral edge of the disk, each of said chambers being comprised of at least one reagent chamber disposed at an angle which is less than a right angle to the direction of the force created by the centrifugal field, a sample chamber disposed at an angle which is less than a right angle to the direction of the force created by the centrifugal field, communicating with and adjacent to said reaction chamber, the depth of which is less than said reagent chamber, and a transfer chamber communicating with and adjacent to said sample chamber and disposed at an angle which is greater than a right angle to the direction of the force created by the centrifugal field, said reagent chamber being closest to the center of the disc, the transfer cham- 4 her being closest to the peripheral edge of the disc, and the sample chamber being locatedbetween the reagent chamber and the transfer chamber said transfer chamber communicating to the outer peripheral edge of said disk.
2. The device of claim 1 wherein the point in the sample chamber at which the bottom meets the wall closest to the peripheral edge of said disk, is curved.
3. The device of claim 1 wherein the wall of the sam-. ple chamber closest to the peripheral edge of said disk rises up to a point which is below the surface of said disk.
4. The device of claim 1 wherein said chambers are of essentially cylindrical shape.
5. The device of claim 1 wherein said transfer chamber communicates to the outer peripheral edge of said disk by means of an exit port located at the bottom of said chamber.
References Cited UNITED STATES PATENTS 3,532,470 10/1970 Rochte 23-253 3,555,284 1/1971 Anderson 23-253 X 3,586,484 6/1971 Anderson 23-230 MORRIS O. WOLK, Primary Examiner R. E. SERWIN, Assistant Examiner US. Cl. X.R.