1. Field of the Invention
The present invention relates to a dispensing apparatus, a dispensing method, and an automatic analyzer.
2. Description of the Related Art
Conventional automatic analyzers that analyze a biological sample such as blood and other body fluids utilize a dispensing apparatus to dispense a liquid specimen including a reagent into a reaction vessel or receptacle. To dispense liquid specimens of a wide range of viscosities with high accuracy, a dispensing apparatus is known that measures air volume in the dispensing nozzle at the start of discharge of a liquid specimen. Based on the air volume, the dispensing apparatus calculates how far to push the plunger to dispense a desired amount of the liquid specimen (e.g., see Japanese Patent Application Laid-open Publication No. 2004-20320).
A dispensing apparatus according to an aspect of the present invention includes a dispensing nozzle that moves between a first position and a second position, and sucks in a liquid specimen at the first position to dispense the liquid specimen into a vessel located at the second position. The liquid specimen contains a specimen or a reagent. The dispensing apparatus also includes an agent applicator that is located on the path of movement of the dispensing nozzle, and applies, to the discharge end portion of the dispensing nozzle, an agent having a low affinity for the liquid specimen than the inner surface of the dispensing nozzle.
A dispensing method according to another aspect of the present invention includes sucking in a liquid specimen containing a specimen or a reagent through a dispensing nozzle; discharging the liquid specimen; cleaning the dispensing nozzle; and applying, to the discharge end portion of the dispensing nozzle, an agent having a low affinity for the liquid specimen.
The above and other objects, features, advantages and technical and industrial significance of this invention will be better understood by reading the following detailed description of presently preferred embodiments of the invention, when considered in connection with the accompanying drawings.
Exemplary embodiments of the present invention are explained in detail below with reference to the accompanying drawings.
As shown in
The first reagent table 2and the second reagent table 3 are of like construction and thus but one of them, the first reagent table 2, is described in detail below. Corresponding reference characters refer to constituent elements of the second reagent table 3 corresponding to those of the first reagent table 2.
To illustrate with reference to
The reaction table 5 is provided thereon with a plurality of reaction vessels 6 along the circumferential direction as shown in
Each of the reaction vessels 6 is a rectangular cylindrical cuvette with a small capacity of a few nanoliters to several tens of microliters. The reaction vessels 6 are made of a transparent material that transmits not less than 80% of analytical light emitted by the photometer 22. Examples of such material include glass such as heat-resistant glass and synthetic resin such as cyclic olefin and polystyrene. Into the reaction vessels 6, the first reagent dispensing apparatus 7 and the second reagent dispensing apparatus 8 located near the reaction table 5 dispense reagents from the reagent vessels 2a and 3a on the first reagent table 2 and the second reagent table 3, respectively.
The first reagent dispensing apparatus 7 and the second reagent dispensing apparatus 8 are of like construction and thus but one of them, the first reagent dispensing apparatus 7, is described in detail below. Corresponding reference characters refer to constituent elements of the second reagent dispensing apparatus 8 corresponding to those of the first reagent dispensing apparatus 7.
The first reagent dispensing apparatus 7 rotates in directions indicated by a two-headed arrow shown in
The specimen vessel conveyor 9 conveys a plurality of racks 9a in directions indicated by arrows in
As shown in
The dispensing nozzle 11 is formed by, for example, machining metal such as stainless steel or injection-molding synthetic resin such as polystyrene. The dispensing nozzle 11 includes, as shown in
The nozzle driving mechanism 12 moves the dispensing nozzle 11 up and down as well as rotating it. As shown in
The pump driving mechanism 15 causes the dispensing nozzle 11 to dispense a specimen and, as shown in
The pump 16 pumps a cleaning fluid contained in the washing tank into the cylinder 15b of the pump driving mechanism 15. The valve 17 switches the flow of the cleaning fluid through the pipe 15h that connects between the washing tank and the pump driving mechanism 15.
The agent applicator 18 is, as shown in
The fixation promoting unit 19 is located on the path of movement of the dispensing nozzle 11, and blows air or hot air to the discharge end portion 11b of the dispensing nozzle 11 with a blower or a blower with heater. By drying the agent, such as a fluoropolymer solution or a silicone resin solution, applied to the discharge end portion 11b of the dispensing nozzle 11, the fixation promoting unit 19 promotes fixation of the agent.
As shown in
The photometer 22 is located between the stirrer 21 and the cleaner 23 as shown in
As shown in
The control unit 25 can be, for example, a microcomputer, and is connected to each constituent element of the automatic analyzer 1 as shown in
The automatic analyzer 1 configured as above operates under the control of the control unit 25. Thus, the specimen dispensing apparatus 10 sequentially dispenses specimens from the specimen vessels 9b held by the racks 9a into the reaction vessels 6 transported along the circumferential direction of the rotating reaction table 5. Into the reaction vessels 6 having a specimen dispensed therein, the first reagent dispensing apparatus 7 and the second reagent dispensing apparatus 8 sequentially dispense reagents from the reagent vessels 2a and 3a, respectively.
Each time the reaction table 5 stops rotating, the stirrer 21 stirs the reagent and the specimen dispensed into the reaction vessels 6. As a result, the reagent and the specimen react with each other. When the reaction table 5 restarts rotating, the reaction vessels 6 pass through the photometer 22. The photometer 22 performs photometry on the reaction solution resulting from the reaction between the reagent and the specimen in the reaction vessels 6. The control unit 25 then analyzes the constituent concentration and the like. After the completion of photometry by the photometer 22, the reaction vessels 6 are sent to the cleaner 23 where they are cleaned to be used again for the analysis of a specimen.
As described above, according to the embodiment, the specimen dispensing apparatus 10 includes the agent applicator 18 that applies an agent to the discharge end portion 11b of the dispensing nozzle 11. The agent is a solution, such as a fluoropolymer solution or a silicone resin solution, having a low affinity for a specimen to be dispensed than the inner surface of the cylindrical portion 11a of the dispensing nozzle 11. This allows the specimen dispensing apparatus 10 to apply the agent to the discharge end portion 11b of the dispensing nozzle 11 as required. For example, under the control of the control unit 25, the specimen dispensing apparatus 10 can apply the agent to the discharge end portion 11b of the dispensing nozzle 11 during the analysis of a specimen. A description is given below with reference to
The control unit 25 first cleans the dispensing nozzle 11 (step S100). More specifically, the control unit 25 moves the dispensing nozzle 11 from where it has dispensed a specimen into each of the reaction vessels 6 on the reaction table 5 to the washing tank 10d for cleaning the dispensing nozzle 11. Thereafter, the control unit 25 rotates the dispensing nozzle 11 in the horizontal direction to move it from the washing tank 10d to just above the agent applicator 18 (step S102).
Subsequently, the control unit 25 moves down the dispensing nozzle 11 to apply an agent to the discharge end portion 11b (step S104). The pressure sensor 18b detects the pressure on the agent applicator 18 when the dispensing nozzle 11 moves down and the discharge end portion 11b is brought into contact with the agent applicator 18. The pressure sensor 18b outputs a pressure signal to the control unit 25 based on the detected pressure. Based on the pressure signal received from the pressure sensor 18b, the control unit 25 checks the application of the agent to the discharge end portion 11b (step S106).
More specifically, the control unit 25 compares the pressure signal received from the pressure sensor 18b of the agent applicator 18 with a threshold signal relative to a predetermined pressure threshold. Based on the comparison, the control unit 25 determines whether the agent has been applied appropriately to the discharge end portion 11b of the dispensing nozzle 11. Having determined that the agent has not been applied appropriately, the control unit 25 displays this information on the display unit 27 and also causes the specimen dispensing apparatus 10 to apply the agent again to the discharge end portion 11b.
Having determined that the agent has been applied appropriately, the control unit 25 moves up the dispensing nozzle 11 to its original position (step S108). Thereafter, the control unit 25 rotates the dispensing nozzle 11 in the horizontal direction to move it from the agent applicator 18 to just above the fixation promoting unit 19. The fixation promoting unit 19 promotes fixation of the agent (step S110) Thus, the agent applied to the discharge end portion 11b of the dispensing nozzle 11 is fixed as the non-affinity film 11d.
The control unit 25 then rotates the dispensing nozzle 11 in the horizontal direction to move it from the fixation promoting unit 19 to above one of the specimen vessels 9b held by one of the racks 9a (step S112). Subsequently, the control unit 25 moves down the dispensing nozzle 11 to suck a specimen from the specimen vessel 9b (step S114).
The control unit 25 moves up the dispensing nozzle 11, and rotates it in the horizontal direction to above one of the reaction vessels 6 (step S116). Subsequently, the control unit 25 moves down the dispensing nozzle 11 to dispense the specimen into the reaction vessel 6 (step S118).
As described above, to the discharge end portion 11b of the dispensing nozzle 11, the agent applicator 18 applies an agent having a low affinity for a specimen to be dispensed than the inner surface of the cylindrical portion 11a. Accordingly, even specimens of a wide range of viscosities can be dispensed without dropping. Moreover, specimens of a wide range of viscosities can be dispensed highly accurately with less variation in the dispensed amount of the specimens.
The dispensing performance of the specimen dispensing apparatus 10 was tested using different types of dispensing nozzles, i.e., the dispensing nozzle 11 of this embodiment (Example 1) and a comparative nozzle (Comparative Example 1). The dispensing nozzle 11 used in the test was made of stainless steel and the end thereof was coated with the non-affinity film 11d made of fluoropolymer. The comparative nozzle was basically similar to the dispensing nozzle 11 except having no coating of the non-affinity film 11d. Under the condition that the target amount of test specimens, one having a viscosity of 1 mpa·s and the other having a viscosity of 3 mPa·s, to be dispensed was set to 0.4 microliter, the amount (microliter) of the test specimens actually dispensed (discharged) was measured. The viscosities of the test specimens were determined based on the viscosity of human blood.
The test results are shown in Table 1 with dispensed amount difference (%) based on the actual dispensed amount of the test specimen having a viscosity of 1 mpa·s. In the test, the test specimens were dispensed 100 times through the respective nozzles, and the amount of each test specimen actually dispensed was measured each time by measuring the absorbance of a dye dispensed as the test specimen and then diluted. Table 1 shows as the actual dispensed amount the average of the amounts of each test specimen obtained by the 100 times of measurements. The dispensed amount difference (%) is on the basis of the average of the amounts of each test specimen actually dispensed, and is obtained as follows: (the dispensed amount difference/the actual dispensed amount of the test specimen having a viscosity of 1 mPa·s)×100.
As shown in Table 1, compared to the comparative nozzle, the specimen dispensing apparatus 10 can reduce the dispensed amount difference (%) to about a half with the dispensing nozzle 11. That is, according to the embodiment, with the dispensing nozzle 11 having the non-affinity film 11d coated on the discharge end portion 11b, the specimen dispensing apparatus 10 can dispense liquids of different viscosities with little variation in the amount of dispensed liquids. Thus, it is possible to dispense liquid specimens of a wide range of viscosities with high accuracy.
In the description given in connection with
Examples of the agent having a low affinity for a specimen than the inner surface of the dispensing nozzle 11 include fluoropolymer solutions such as trade name: FluoroSurf-FG-3020TH-8.0 manufactured by Fluoro Technology Co. Ltd., and silicone resin solutions such as trade name: HIREC-1550 manufactured by NTT Advanced Technology Corporation and trade name: Rain-X manufactured by Shell Car Care International Ltd. When such an agents is applied to the discharge end portion 11b, the dispensing nozzle 11 can be used for the dispensing operation even if the agent is not fully dried and not fixed as the non-affinity film 11d since the agent has a low affinity for a specimen.
While the agent applicator 18 is described as a pad impregnated with an agent such as a fluoropolymer solution or a silicone resin solution, it can be a sheet 31 coated with an agent 31a made of fluoropolymer or silicone resin. In this case, the dispensing nozzle 11 moves down to bring the discharge end portion 11b into contact with the sheet 31 so that the agent 31a is applied to the discharge end portion 11b. After that, by drying the agent 31a at ordinary temperature or high temperature, a non-affinity film having a low affinity than the inner surface of the cylindrical portion 11a can be formed on the discharge end portion 11b. The sheet 31 extends around two rollers 32. Each time the agent 31a is applied to the discharge end portion 11b, one of the rollers 32 rolls up the sheet 31. Below the sheet 31 is arranged a pressure sensor 33 that detects the pressure on the sheet 31 from the discharge end portion 11b in contact therewith.
The agent applicator 18 can also be, as shown in
In addition, the end portion of the dispensing nozzle 11 used in the specimen dispensing apparatus 10 is described as being tapered. However, the end portion of the dispensing nozzle is not necessarily tapered, but can be of a straight pipe.
Besides, the agent applicator 18 is provided to apply an agent to the dispensing nozzle 11 of the specimen dispensing apparatus 10 in the above embodiment. Similarly, an agent applicator can be provided to apply an agent to, for example, the dispensing nozzle 7b of the first reagent dispensing apparatus 7 and the dispensing nozzle 8b of the second reagent dispensing apparatus 8. In this case, the agent applicator is located between the reagent vessels 2a and the washing tank 7c for cleaning the dispensing nozzle 7b, and between the reagent vessels 3a and the washing tank 8c for cleaning the dispensing nozzle 8b.
Additional advantages and modifications will readily occur to those skilled in the art. Therefore, the invention in its broader aspects is not limited to the specific details and representative embodiments shown and described herein. Accordingly, various modifications may be made without departing from the spirit or scope of the general inventive concept as defined by the appended claims and their equivalents.
Number | Date | Country | Kind |
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2007-226971 | Aug 2007 | JP | national |