JPH0373812B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention first provides a set of small analysis chambers, a central distribution chamber, and a set of small analysis chambers arranged around the small analysis chambers and the central distribution chamber. distribution cavities disposed between the central distribution chambers, each of said distribution cavities having an inlet connected to said central distribution chamber and an outlet connected to one of said analytical chambers by a transfer passage. and further comprising at least one overflow sump connected to the inlet of the distribution cavity by at least one communicating passage.

Analyzes in clinical chemistry are performed using very small amounts of samples, and the accuracy of the analysis results largely depends on the accuracy of the amounts of samples and reagents.
Therefore, this accuracy is greatly influenced by the pipette, and it is difficult to guarantee analytical results when the amounts of sample and reagent are small. As a result, pipettes with high precision have been developed that are very expensive. In addition, the pipetting operation of each analyzed sample and each portion of reagent must be repeated, thus preparing a set of samples and reagents for analysis in the rotor of the centrifuge analyzer. This process usually takes longer than the analysis itself.

Another essential factor regarding the accuracy of the analysis is the determination of when the reaction begins, ie, when the sample is placed in the presence of the reagents. This is arranged around an analytical rotor in which the chambers introduce reagents and/or samples and have chambers in communication with the respective chambers, the contents of which are transferred to the chambers by the centrifugal force acting on the liquid during centrifugation of the rotor. This is the reason why it is distributed to the small rooms at the same time.

In US Pat. No. 3,873,217 it has already been proposed to measure and distribute a portion of the liquid into analytical chambers arranged around the rotor. Measurements are performed as described below. The liquid injected into the central distribution chamber is divided into various analysis units by equidistantly spaced edges or protrusions around the periphery of the central distribution chamber. As the rotor rotates and the liquid is divided by equidistantly spaced edges, the liquid is forced into a plurality of analysis units. Since the above-mentioned dispensing precision is low and depends in particular on the amount of liquid introduced into the central distribution chamber, a precise amount of liquid must be pipetted.

According to US Pat. No. 3,744,975, a distribution similar to that described in said US patent is carried out by using an overflow sump. The liquid portions are simultaneously distributed into the chambers by sending a stream of pressurized air. This does not guarantee that a very precise volume of liquid will be transferred.

The object of the invention is to dispense samples and/or reagents with high precision using a device of simple construction and adapted to be mass-produced at a reasonable cost, by subsequently dispensing liquid parts simultaneously. The aim is to avoid the disadvantages of the previously mentioned methods.

The analytical rotor according to the invention is designed to prevent the liquid from flowing into the analytical chamber until the centrifugal force acting on the liquid exceeds a certain threshold value, which is greater than the resistance to the liquid flowing through the communication passage. It is characterized in that the holding device is combined with a transfer channel.

The invention also provides for a volume of liquid greater than the total volume of the distribution cavity to be introduced into the distribution chamber to fill said distribution cavity with liquid and to discharge excess liquid into an overflow sump. The rotor is driven at a first speed, thereby exerting a centrifugal force on the liquid that is greater than the resistance to the liquid flowing through the communication and less than the threshold value, and exerts a centrifugal force on the liquid that is greater than the threshold value. characterized in that the speed of the rotor is changed to a second speed greater than the first speed in order to act on the liquid and thereby transfer a portion of the liquid contained in the distribution cavity to the respective analysis chamber. This article relates to how to use a rotor for analysis.

The accompanying drawings schematically illustrate various embodiments and variants of the analytical rotor according to the invention.

1 and 2 show an analytical rotor in the form of a disk 1 with a set of analytical chambers 2 regularly distributed around the circumference. The central region of the analytical rotor serves as a distribution chamber 3 which communicates axially with the outside via a central hole 4 formed in the top surface 5 of the analytical rotor. The bottom of the distribution chamber 3 is designed in the form of a dish with a flattened central region and an annular frustoconical edge. The peripheral portion of the distribution chamber 3 communicates with a set of triangular cavities 6. All cavities 6 are separated from each other by a projection or edge 7 formed by the intersection of two adjacent sides of each cavity. All protrusions 7
are on one common circle. The base of each triangle adjacent to the circle opens into the distribution chamber 3 and forms an inlet 8 of each cavity 6. The end of each cavity 6 extends below the edge of the distribution chamber 3. The apex of each triangle facing the open base has an outlet hole at the end of the transfer channel 9 connecting each distribution cavity 6 to the analysis chamber 2.
As shown in FIG. 2, the edge formed by the apex of the triangular cavity 6 adjacent to the transfer passage 9 forms an angle of less than 180° and with respect to a radius passing through the end of the transfer passage 9. It is practically symmetrical.
This shape facilitates emptying of the cavity 6 by the action of centrifugal force.

The transfer channel 9 is equipped with a capillary duct. The cross-section of the capillary duct is selected such that the resulting capillary action maintains a cohesive meniscus of the liquid at the outlet of the transfer channel 9. For this purpose, each passage 9 is located parallel to the axis of rotation of the rotor 1 and halfway from the top and bottom surfaces of the chamber 2 in order to substantially reduce the risk of destabilizing the resulting meniscus. It opens into the surface of the small chamber 2.

The inlet 8 of the distribution cavity 6 adjoins the annular wall 10 . The annular wall 10 shields the inlet 8, and the top surface of the annular wall 10 forms an inclined surface starting from an edge 11 adjacent to the inlet 8. This inclined surface terminates in a collection section 12. The bottom of the collection part 12 has a hole 13 for accessing a triangular overflow sump 14 inserted between two adjacent distribution cavities 6. The cross-section of each hole 13 is sufficiently large to prevent capillary forces from acting on the liquid flowing through the hole.

Each chamber 2 has two windows 1 arranged opposite to each other along an axis parallel to the axis of rotation of the rotor 1.
5. The window 15 is formed for photometrically measuring the contents in the chamber 2.

The rotor 1 is manufactured by injection molding of transparent plastic. In the embodiment, each part of the rotor 1 on either side of the midplane M is molded separately;
And the same method is applied to the top surface 5. The material used is UV transparent and in this case is unstabilized polymethyl methacrylate sold by ICI under the registered trademark DIAKON. The various injection molded parts are preferably cured before being bonded together using a pure solvent such as chloroform or dichloroethane. These parts can also be assembled by ultrasonic welding.

The rotor 1 is used as described below. The rotor 1 is placed on the drive plate of an analysis device (not shown). A volume of reagent is introduced into the dispensing chamber 3 and the rotor 1 is rotated for 4 to 8 seconds.
It is rotated at a first speed of about 600 rpm.
At this speed, the liquid in the distribution chamber 3 is ejected by centrifugal force into the distribution cavity 6 and opens by capillary action through the various transfer channels 9 into the vertical walls of the respective analysis chamber 2. Move to the end of the transfer path. A stable meniscus is formed at the end of the transfer channel 9, which prevents the air enclosed in the chamber 2 from escaping. Also, since the chamber 2 is sealed, the air trapped in this way prevents the liquid from entering the chamber 2, and the centrifugal force transmitted to the liquid at the rotational speed of 400 to 600 rpm mentioned above is transferred to the chamber 2. is insufficient to overcome the resistance due to the volume of air trapped within. The amount of reagent introduced into the dispensing chamber 3 is intentionally larger than the total volume of the dispensing cavity 6, so that even after the dispensing cavity 6 has been filled with liquid, no excess liquid remains therein. remains. Excess liquid is then driven off into the annular collector 12 along the sloped top surface of the annular wall 10 . Holes 13 are formed in the bottom of the collection section 12 to allow liquid to flow into various overflow reservoirs 14 . As a result, only a portion corresponding to the volume of the distribution cavity 6 remains around the distribution chamber 3, and the overflow device ensures that the entire volume of the distribution cavity 6 is filled with liquid and that the measured volume is very accurate. I guarantee that there is.

In the second step, the speed of the rotor 1 is rapidly increased to 4000-5000 rpm for 2-5 seconds. At this speed, the centrifugal force acting on the portion of the liquid held within the distribution cavity 6 becomes large enough for the pressure of the liquid to break the meniscus and thereby escape from the chamber 2 through the passageway 9. , the liquid can therefore gradually flow into the chamber 2, alternating with the inflow of droplets of liquid and the outflow of bubbles until all the liquid has been transferred from the distribution cavity 6 into the chamber 2. Also, the transfer of liquid from the distribution cavity 6 to the chambers 2 occurs simultaneously for all chambers 2.

If a sample has already been introduced into the chamber 2, a reaction will begin between this sample and the reagent flowing into the chamber. Then, in order to measure the change in absorbance of the sample during this reaction using a known method, measurements are taken through the window 15 after reducing the rotor speed to 400 to 600 rpm.

On the other hand, if the sample is not placed in the small chamber 2, it is necessary to remove the sample from the cavity 6 to the small chamber 2.
After the reagents have been introduced into the distribution cavity 6, the sample can be introduced into the distribution cavity 6 by means of a pipette. In this case, the amount of sample must be less than the amount that the distribution cavity 6 can accommodate while at rest. Otherwise, adjacent different samples will mix with each other.

After the sample has been introduced into the distribution cavity, it contacts and mixes with the reagents already introduced, while being centrifuged at 4000 to 5000 rpm and forced into the respective chamber 2;
And after the rotor speed has been reduced to 400 to 600 rpm, the measurement is started.

The design of the analytical rotor described above is such that due to the capillary action of the passages 9, which maintains the meniscus formed by cohesive forces, the distribution cavities, i.e., the distribution chamber 6 and the chamber 2,
It is entirely based on holding liquid between
Said meniscus cooperates with the air in the sealed chamber 2 to prevent air from escaping, thus introducing liquid into the chamber 2 unless a sufficient pressure differential is applied to destroy the meniscus. I can't.
On the other hand, the resistance to the flow of excess liquid into the overflow sump is considerably lower. As a result, when the distribution cavity 6 is filled with liquid up to the respective inlet, excess liquid is directed along the slope of the wall 10 and through the annular duct 12 and the hole 13 into the overflow sump 14. The holes 13 are also sized to allow air to escape and liquid to be introduced at the same time. After increasing the pressure of the liquid as a result of generating centrifugal force by increasing the speed of the rotor from 400 to 600 rpm to 4000 to 6000 rpm, the liquid is transferred from the distribution cavity 6 to the chamber 2. This transfer method applies a force to each portion of the liquid and ensures a complete distribution of the liquid in the chamber 2, thereby ensuring that accurate measurements are taken within the chamber 2. This result cannot be guaranteed when the transfer is carried out by means of a pressurized fluid acting on the liquid to be transferred, as proposed in the prior art. Of course, other devices different from those described above could be devised to retain the liquid in the distribution cavity, such as valves that are selectively opened and closed. However, a very great advantage of the liquid holding device described above, namely the combination of a closed chamber 2 and the air trapped therein with a passage 9 or a corresponding passage 28, is that the structure of this liquid holding device is completely The rotor is static in nature and can be obtained only by configuring the main parts of the rotor to suitable dimensions. Analytical rotors can thus be obtained at a price comparable to known analytical rotors by injection molding and welding. This analytical rotor can be used in existing centrifugal analyzers and requires only a less precise pipette to introduce the reagent portion into the distribution chamber 3.

3 and 4 show an embodiment that differs from the previous embodiment primarily in that the analytical rotor 16 has only two diametrically opposed overflow reservoirs 17. There is. The distribution cavity 6 and the analysis chamber 2 are similar in all respects to the previously described embodiment. Therefore, in this specification, the overflow reservoir 17
Only the structure of will be described in detail.
The overflow reservoirs 17 are connected to the central distribution chamber 3 by respective communication channels 18 at the ends of the recesses 19 . Each recess 19 is defined by two edges 7 intersecting between adjacent sides of two distribution cavities 6 and an edge of each recess 19;
The edges of the recesses 19 are thereby arranged at the same radial distance from the axis of the rotor as the inlets of the various distribution cavities 6.

The interior of the overflow sump 17 is connected to two adjacent lateral chambers 20 near the entrance of the passage 18 into each overflow sump. The chamber 20 is the rotor 16
It is in communication with the outside atmosphere by a hole 21 formed through the top surface. As a result, the resistance to liquid flowing into the overflow sump 17 is lower than the resistance at the entrance to the chamber 2. The reason is that overflow liquid puddle 1
7 communicates with the atmosphere through the hole 21, while the chamber 2 is sealed as soon as the liquid closes the transfer passage 9.

During low-speed centrifugation (400-600 rpm), the reagent introduced into the distribution chamber 3 is forced into the distribution cavity 6 and into the recess 19. Two streams are passage 18
Since all the edges 7 lie along a single radius, excess liquid inside the radius passing through the edges 7 flows towards the recess 19 and into the overflow sump 1.
7.

A volume of air corresponding to the volume of liquid introduced freely escapes into the atmosphere through the holes 21. A barrier separates each overflow sump 17 into two compartments. This barrier extends from one edge of the overflow sump 17 to the other edge leaving an intermediate passageway 22a. The intermediate passage 22a is designed to prevent backflow of liquid during the subsequent mixing operation of the liquid reagent and sample due to subsequent rocking of the analysis rotor.

FIG. 5 shows a modified embodiment. The only difference between this embodiment and the embodiments of FIGS. 3 and 4 is the presence of circular grooves 23 formed in the bottom and top walls of the distribution chamber 3 adjacent to the edge 7. . The grooves 23 are adapted to help maintain the meniscus at the entrance 8 of the dispensing cavity 6 and improve the accuracy of dispensing.

6 and 7 show another variation of the embodiment of FIGS. 3 and 4. FIG. In addition to the groove 23, this variant embodiment comprises a pair of ribs 24 formed in the bottom of the distribution chamber 3. The ribs 24 are arranged on both sides of the passage 18 communicating with the overflow reservoir 17. A rib 24 is provided adjacent to the recess 19 and aligned with each side of the cavity 6. These ribs 24 interrupt the groove 23 and extend to the inside of the circular section defined by this groove 23.
The ribs 24 are adapted to reduce the velocity of fluid flow towards the recess 19. The recess 19 changes the meniscus at the entrance 8 of the cavity 6 adjacent to the recess 19 . In this way, the recess 19 slightly changes the volume of the adjacent cavity 6, but this undesirable influence of the recess 19 is prevented by the ribs 24. It must be remembered that the aim of the invention is to obtain an accuracy of the order of 1% or less so that any sources of error can be excluded.

Through tests conducted using the above rotor,
It has been found that it is possible to obtain the abovementioned accuracy and to reduce the error rate to less than 1%, thus making it equal to the accuracy of the best known pipettes. In addition, since the dispensing takes place without the use of any moving parts and the rotor is used only once and is obtained from a single mold, this dispensing method is not susceptible to any operational failures.

The rotor described with respect to FIGS. 3-7 is constructed by injection molding and has top and bottom portions of substantially equal thickness and is ultrasonically welded as described above.

FIG. 8 shows an embodiment of a rotor 25 specifically designed for bacteriological analysis. Rotor 25
has an analysis chamber 26 connected to the distribution cavity 27 by a passageway 28. The center of the rotor 25 is occupied by a distribution chamber 29.
All inlets of the distribution cavity 27 extend towards the. An overflow reservoir 30 occupies the location of the analysis chamber 26 and is connected to the distribution chamber 29 by three passages 31 . Two of the passages 31 open into the distribution chamber 29 via respective recesses 32 at the ends of the passages, thereby allowing excess liquid to collect and flow through the passages 31, while similar The open duct 31 in the recess allows air to escape from the overflow sump 30 towards the distribution chamber 29 after excess liquid has entered the overflow sump 30. This feature avoids any contact with the outside world, which is important in case of bacteriological analysis. On the other hand, the air coming out of the duct 31 generates bubbles. This bubble may slightly reduce accuracy. However, in the case of bacteriological analysis, accuracy is less important than the risk of contamination.

The top surface of the rotor 25 is covered by a welded plate 33. Plate 33 is for each small chamber 2
6 has an analysis window 34 matched to a similar window formed in the bottom of the 6. The plate 33 has holes 35 for introducing an antibiotic product for testing in the presence of a predetermined bacterial strain, for example. A closure device 36 is provided to seal the chamber 26 after the test product has been inserted. Antibiotic products are "Sensidisc" by "Becton, Dickinson &Co."
It is preferably placed on a holder of the type of hydrophilic paper disks of the type sold under the trademark .

A bacterial fluid culture medium is introduced into the distribution chamber 29 in the same manner as the reagents in the previous embodiments and centrifuged at a first speed to fill the distribution cavity with the culture medium. Excess liquid is directed into the passageway 31 by the recess 32, while air is directed into the passage 31 by the recess 32.
It escapes through the passage 31 without passing through. Once all excess liquid has been transferred to overflow chamber 30, the speed of rotor 25 is increased as described above to force a portion of the liquid into chamber 26. A small chamber 37 (beside the overflow chamber 30) is used as a reference cell.

Alternatively, the rotor can be sold after the chamber has been filled with a predetermined antibiotic product, thereby relieving the user of the filling task. Providing the transfer passage 28 adjacent to the plate 33 reduces the stability of the meniscus at the exit of said passage 28, but simplifies the method of manufacturing the rotor 25, which can be constructed in one piece by injection molding. be able to. In this case, an ordinary plate 33 with holes 35 and windows formed therein is sufficient to close off the top of the assembly of chambers 26 and distribution cavities 27. The precision obtained with the last mentioned embodiment is in full accordance with the precision required for bacteriological analysis. In the case of a pre-filled rotor, the chambers are filled with product before the plates 33 are welded.

The invention described above can be used to simultaneously supply several parts with an accuracy within 1%. Therefore, the dispensing device only replaces most precision pipettes and saves considerable time compared to using a pipette to inject samples/reagents into the rotor. Therefore, the present invention saves investment by replacing precision pipettes and at the same time increases productivity as a result of dispensing. These advantages have heretofore been associated with various disadvantages which have affected accuracy, inter alia in the case of clinical chemistry analyses. The main advantage of the present invention is that it does not require a pipette, has a precise precision that can rival that of most precision pipettes, yet is constructed with two or three injection molded parts similar to the commonly known rotor. The solution is to solve the distribution problem by using a static device resulting from a rotor design that can be assembled by welding. The analytical rotor can therefore be mass-produced at a price that is fully competitive with other analytical rotors not equipped with a dispensing device.

[Brief explanation of drawings]

Fig. 1 is a partially cutaway plan view of the first embodiment of the present invention, Fig. 2 is a cross-sectional view of Fig. 1 taken along the - line, and Fig. 3 is a plan view of the second embodiment. Plan view,
4 is a sectional view of FIG. 3 taken along the - line, FIGS. 5 and 6 are plan views of the modified embodiment of FIG. 3, and FIG. 7 is a sectional view of FIG. 6 taken along the - line. The cutaway sectional view and FIG. 8 are perspective views of the third embodiment. 1...Rotor, 2...Analysis chamber, 3...Distribution chamber, 4...Central hole, 6...Distribution cavity, 7...
Projection, 8... Entrance, 9... Transfer passage, 10...
Annular wall portion, 12... Annular collection section, 13... Hole, 1
4...Overflow liquid pool, 15...Window, 16...Analysis rotor, 17...Overflow liquid pool, 18...Communication passage, 19...Concave portion, 20...Chamber, 21...Hole,
22a...middle passage, 23...groove, 24...rib, 25...rotor, 26...small chamber for analysis, 27
... Distribution cavity, 28 ... Passage, 29 ... Distribution chamber, 30 ... Overflow liquid reservoir, 31 ... Passage, 32 ...
... recess, 33 ... plate, 34 ... analysis window, 35 ... hole, 36 ... closing device, 37 ... small chamber.

Claims (1)

[Claims] 1. A set of analysis chambers 2, 26 arranged around the periphery.
, the central distribution chambers 3 and 29 and the respective analysis chambers 2 and 26, and the analysis chambers 2 and 26.
and a peripheral portion of the central distribution chamber 3, 29, each of said distribution cavities 6, 27 having an inlet connected to said central distribution chamber 3, 29. and an outlet connected to one of the analysis chambers 2, 26 by a transfer passage 9, 28, and at least one communication passage 18, 3.
In an analytical rotor equipped with at least one overflow reservoir 17, 30 connected to the distribution chamber 3, 29 by 1, the centrifugal force acting on the liquid overcomes the resistance of the liquid flowing through the communication channels 18, 31. The analysis is characterized in that a liquid holding device is combined with the transfer passages 9, 28 in order to prevent liquid from flowing into the analysis chambers 2, 26 until the liquid exceeds a high threshold value. rotor. 2. In the analytical rotor according to claim 1, the transfer passages 9, 28 are formed in such a size that a capillary action force is generated in the liquid at one end to generate a meniscus due to a cohesive force. It is noted that the liquid holding device, which is a duct and is associated with said communication passage, contains a volume of air confined in each chamber 2, 26 into which the respective communication passage 9, 28 opens. Characteristic analysis rotor. 3 In the analytical rotor according to claim 2, the transfer passages 9 and 28 are connected to the small chambers 2 and 28.
26. An analytical rotor characterized in that the small chamber 2 is opened at the top in a plane substantially parallel to the rotational axis of the rotor. 4. An analytical rotor according to claim 1, in which the distribution cavities 6 are separated from each other by edges, i.e., protrusions 7, arranged on a common circle concentric with the axis of rotation of the rotor. An analytical rotor characterized in that circular grooves 23 are formed in the top and bottom surfaces of the rotor adjacent to the edges formed between the distribution cavities 6. 5. The analytical rotor according to claim 1, wherein the inlet 8 is located at a higher level than the bottom of the distribution chamber 3 and the bottom of the distribution cavity 6. 6. In the analytical rotor according to claim 1, the analytical chambers 26 are arranged in an arc shape and covered by a plate 33, and the plate is arranged above the analytical chambers 26. a hole 35 communicating with the outside of the rotor;
Analytical rotor characterized in that it has a closing device 36 for 5. 7 A pair of analysis chambers 2, 26 arranged around the perimeter
and a central distribution chamber 3, 29, and a distribution cavity 6, 27 corresponding to each analytical chamber 2, 26 and arranged between said analytical chamber 2 and the peripheral portion of the central distribution chamber 3, 29. and the distribution cavity 6,
27 each has an inlet connected to said central distribution chamber 3 , 29 and an outlet connected to one of said analytical cells by means of a transfer passage 9 , 28 , and furthermore at least one communication passage 18 . , 31 to the distribution chambers 3, 29, the centrifugal force acting on the liquid is higher than the resistance of the liquid flowing through the communicating passages 18, 31. In the method of using an analytical rotor, the transfer passages 9, 28 are combined with a fluid retaining device to prevent liquid from flowing into the analytical chambers 2, 26 until a certain threshold value is exceeded. A volume of liquid greater than the total volume of the distribution cavities is introduced into said central distribution chamber 3, 29, filling said distribution cavities 6, 27 with liquid and overflowing the liquid sump 17, 30. said rotor is driven at a first speed to discharge said liquid through said communication passageway, thereby exerting a centrifugal force on said liquid that is greater than a resistance to said liquid flowing through said communication passageway and less than said threshold value; The speed of said rotor is lower than the first speed in order to exert a centrifugal force on the liquid that is greater than the first speed, thereby transferring a portion of the liquid contained in the distribution cavities 6, 27 to the respective analysis chambers 2, 26. Also big 2nd
A method of using an analytical rotor characterized in that the speed is changed.