一种分立式全自动生化分析仪的研制.doc

The development of a discrete automatic clinical analyzer
TAN Hung—xue‘，LIU Wei。， GUO Qiang。， TANG Yu—guo。
Abstract：The clinical analyzer is general equipment for hospita1．The discrete automatic clinical analyzer for grassroots hospital has been developed by US．This analyzer uses holographic concave grating as spectroscope．The wavelengthis from 340 nm to 800 nm，and its true test speed can reach 300 tests／hour．The analyzer is controlled by a computer．It is connected to computer through RS4 85 serial port．The Visual Basic 6．0 is used as program developlanguage．It is come true that computer automatically controls the clinical analyzer．
Key words：clinical analyzer；automatic control；spectrum apparatus
1 Introduction
Optical analysis as one of the clinical examination and analysis of the most commonly used detection methods are widely used in a variety of medical analytical instruments. Automatic biochemical analyzer is a typical application of this method. Biochemical analyzer is used for determination of human body fluids (blood, urine) in a variety of biochemical indicators (such as blood, liver function, renal function, heart function, blood glucose, lipids, minerals, etc.), analytical instruments, it can accurately quickly provide the necessary test data for doctors and chemical inspectors play an important role in clinical diagnostics and chemical testing.
Automatic biochemical analyzer biochemical analytical instruments as a higher degree of automation, it biochemical analysis of the sample, add reagents, mixing, thermal reaction, detection, the results of calculation and display steps part or all of the manual referred to imitate equipment to complete, rapid processing of samples and greatly improve the accuracy and reliability of operation, reducing manual intervention, with the incomparable advantages of the manual, has an important role in the clinical chemistry tests, hospital inspection conventional equipment.
Automatic biochemical analyzer in accordance with the colorimetric approach can be divided into mobile and discrete two categories. Discrete and mobile main difference is that control different timing and spectrophotometer. Mobile automatic biochemical analyzer cuvette Use of Mobile and its low speed of analysis, accuracy is also difficult to reach a higher level, the sample cross-contamination; discrete automatic biochemical analyzer using discrete cuvette with each other between no crossCross contamination, the number can be placed according to the needs cuvette, the instrument accuracy and test speed can be greatly improved.
Not yet completely independent research and discrete automatic biochemical analyzer, this is mainly because it involves many optical, mechanical, electrical, calculation, liquid line, temperature control, biochemical analysis, the complexity of the system structure, control the timing demanding requirements of operational reliability and accuracy, so most of the needs of medical institutions to rely on imports. In order to break the monopoly of foreign automatic biochemical analyzer, the Ministry of Science and Technology in 1995 and 15, has earmarked special funds for scientific and technological research, the current 15 scientific and technological research focus is to achieve the industrialization of automatic biochemical analyzer
2 the basic principles
"Ultraviolet and visible spectrophotometry (Ultraviolet-visible Spectrophotometry, uV-Vis)" according to the material elements of the absorption characteristics of the UV and visible spectral regions and extent of absorption of substances qualitative and quantitative analysis of an absorption spectrometry. Analysis of the material content of the clinical examination in the blood of the automatic biochemical analyzer is the application of this method, according to the color reaction in analytical chemistry, biochemical reagents of different substances through the shades of color reaction, Lambert Bill The law of quantitative analysis of its concentration. Lambert-Beer's law expression as follows:
A=lg(I。／I)= εbc(1)
In this formula, A an absorbance; An incident radiation intensity; for a through radiation intensity; b for closing the layer thickness (cm); absorbing compounds the molar concentration (M); ε is ~ is the molar absorptivity (L • mol.cm)
From the above equation, the molar absorption coefficient ε and absorption layer thickness b is a constant, absorption of the molar concentration of c absorbance A is proportional to, can be calculated by measuring the absorbance A of the absorber of the molar concentration c. This law is widely used in UV-visible, one infrared spectral region absorption measurements, the inspection of various biochemical indicators in the automatic biochemical analyzer according to this law of.
3 overall design summary
Prototype of the proposed design for the discrete automatic biochemical analyzer, as a large optical precision instruments, the prototype including the optical system, implementation and operating system, the fluid path system, electronics and computer control system, the measurement principle shown in Figure 1 below. The prototype test speed of 300 tests / hour, using disposable cuvette, the main components and functions are introduced as follows:

Fig．1 The principle of analyzer
The sample a reagent turntable: used to load samples and reagents and accurately delivered to the reagent extraction location and sample extraction location. The turntable divided into inside and outside laps, the inner bearing reagents, 24 reagent bit; outer bearing samples, including 48 sample spaces.
Reaction plate: used to carry the reaction cup and accurate delivery of the reaction cup reagents release position, the sample position and the test liquid extraction location.
Reaction cup area to maintain a constant temperature 37 ± 0.1 ° C, so that the reagents and samples in the reaction cup full response. The reaction plate 108 reaction cup-bit, using the water bath to maintain the temperature of the reaction cup.
The sample extract institutions: used to take samples from the sample cup, and released into the reaction cup. Sample volume: 2μL ~ 60 μL sample accuracy: a 5μL 2μL ≤ ± 2%; the 6μL a 60 μL ≤ ± 4%.Reagents to extract bodies: extraction reagent from the reagent cup, and released into the reaction cup to go.
Reagent volume: 30μL to 800μL ≤ ± 1%.The fluid path system: water supply, drainage, both inside and outside cleaning of the needles used to complete the entire instrument to control water bath.
Optical system: the concave grating beam splitter, the output of 340nm ~ 800nm ​​l2 a characteristic wavelength, 12 pre-amplifier, Photometric range 0 ~ 2.5ABS 12 v/50 the W halogen light source, measurement repeatability: 2mABS .
4 Control System Design
The hardware design of the instrument using a distributed multi-CPU control, three dial sports core, three single-chip independently of each turntable rotation and the corresponding sample, lofting, cleaning and other operations.
The host computer Pc machine, the next bit machine using a microcontroller (89c51) through the RS485 serial interface between PC and machine communication. The task of the next machine is a PC to receive control commands and the completion of implementation of action; PC task is to work timing down bit machine to send control commands to complete the test task.
The software is the soul of the automatic biochemical analyzer. On the one hand to ensure that users can engage in a dialogue with the host computer, on the other hand to command communication between host computer and the next crew. Calculation, calibration and analysis of photometric measurement of a variety of data returned by the operation of the various components of the software-controlled instruments, to ensure that the instrument state, came to the conclusion of the test results, print out the inspection report as a diagnostic basis.
The system design of the software key is to control the execution of many organizations and movements and timing complex and demanding. Reaction disk rotation, rotation of the sample tray and sample needle cleaning, and for sampling and sample loft reagent needle cleaning reagent disk rotation, taking the Reagent put reagents, read the measurement data in the action to complete the cycle of an action, and action institutions to coordinate and cooperate with each other to complete the test and analysis tasks, one part of a problem, the instrument can not operate normally.

Fig．2 The whole structure of analyzer
4.1 MCU assembler design
Microcontroller monitoring and control of the corresponding electrical signal and switch to control the operation of various components and agencies. Control requirements: to receive and execute the control commands to the host sends to the PC to return on the current operating status.
4.2 Master software design
1) Software RequirementsThe master control program requires user input and output interface, system information displays, alarm systems, database storage and processing, report generation and printing as well as lower machine communication function.
2) development platform
The programming language selected the Enterprise Edition of Microsoft Visual Basic 6.0 Chinese, it can be fast and efficient development to meet the actual needs of the application, won the favorite of the majority of engineering and technical personnel, is to use a programming language.
3) the control part
a)Establish a communication protocolTo simplify the host computer and the next bit machine of communication, communication commands a uniform format, format is as follows: 'the next bit machine address' 'communications command', 'parameter' ⋯ 'calibration and', 'end marker'. Command to the array is stored, according to the choice of test parameters to determine the order parameter, initialization commands an array of values.
b) The task numberPC through four microcontroller to achieve control of the instrument, in which each institution is microprocessor controlled the action in accordance with the fixed sequence of actions, so that you can be microprocessor controlled institutions in order segments, and the number host computer in accordance with the order of the microcontroller to send control commands, constantly scan the state of the microcontroller, you can achieve the distributed control of the whole instrument.
Present bit machine after receiving the control command of the host computer, each microcontroller received the first in the command string (the address bits), and determine whether the bit is equal to its own address, if it is its own address, continue to receive entire command string, and ordered to complete the task, the task is completed, up the computer returns Idle notice
4) procedures for fault tolerance
A variety of foreseeable errors and exceptions judgment, set the error handler. When an exception occurs, notify the application to set up and activate the error trapping where the error handler. To write an error handler, all foreseeable errors and make the appropriate response to the implementation of error-handling exit program branching, and notify the user.
5 experimental conclusions and outlook
The prototype performance testing, including sample error, stability, accuracy, clinical comparison test, measurement methods and measurement results are as follows:
1) sample error sample: sample sample range 2μL ~ 60 μL, 60 μL, respectively, to test the injection volume 2μL, the test results shown in Table 1;
2) reagent pipetting error: reagent volume of 60 μL ~ 800μL of reagent amount of 60 μL, 800μL were tested, the test results shown in Table 2;
3) The stability test: the absorbance of 0.504 sodium nitrite solution at 340nm wavelength measurement, measurement 10min every 30s measurements were obtained 2O measurements, as shown in Table 3;
4) the accuracy of the test: the test results shown in Table 4;
5) Comparative clinical testing: clinical patient serum with a Hitachi 7170 automatic biochemical analyzer for clinical comparison test, the test data shown in Table 5.
As can be seen through the above test data, stable and reliable operation of the prototype, fully meet the needs of clinical use.
Automatic biochemical analyzer dependent on foreign imports, so the development of our own reliable automatic biochemical analyzer, both from the development of domestic equipment manufacturing level, or to meet our growing needs of the automatic biochemical analyzer are necessary and urgent.

Table 1 Sampling error of analyze

Table 2 Reagent pipette elTor of analyzer

Table 3 Stability test result of analyzer

Table 4 Veracity test result of analyzer

Table 5 The contrast test data of analyzer
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