Design And Implementation Of Portable Fluorescence Quantitative Detector

Fluorescence quantitative immunochromatography test strip is an effective method for the rapid,accurate and stable detection of aflatoxin and other small molecule harmful substances.But the corresponding fluorescence detector has not been commercialized so far,so it is difficult to realize the quantitative judgment of the test result of the strip.Therefore,a portable fluorescence immunochromatography analyzer was designed and implemented in this paper.We detected the fluorescence intensity emitted by fluorescent markers,established the quantitative model of light intensity ratio and concentration with relevant algorithms,the qualitative and quantitative detection of the target was achieved.The main research results of this paper divided into the following parts: 1.Studyed the principle of fluorescence detection based on laser-induced fluorescence technology,designed the optical detection mechanism based on this principle.Carried out the overall design of the system,including the composition of each part of the testing platform and the design parameters that the system needs to achieve.2.Designed the hardware circuit inside of this portable fluorescence detection equipment.It included embedded system based on two-piece STM32 dual-chip system;driver module;signal acquisition and processing module;human-computer interaction module which used touch screen and system storage module which used EEPROM and NAND FLASH combined dual storage scheme.The filter circuit in the signal acquisition circuit is mainly designed,and the trap circuit was added after the amplifier circuit for filtering,which greatly improved the effect of suppressing photoelectric signal noise at the hardware level.3.Designed software system of the detector.The software development environment was built,then according to software requirements,designed and developed six modules including startup self-test module;main program module;measurement module;data storage module;upper computer communication module and printing module.4.Design of the framework of the detection algorithm,including the mathematical model of light intensity and concentration based on curve fitting based on the least square method,and the denoising filtering algorithm of the system.In the design of filtering algorithm,the design of single filtering algorithm is abandoned.By using the composite denoising algorithm of sliding average filter and wavelet transform,the high frequency noise and low frequency burst noise are effectively suppressed,and the signal-to-noise ratio of the instrument and the accuracy of detection results are greatly improved.5.With aflatoxin B1 as the object,the developed detector has been tested and verified for many times.The results show that the minimum detection limit of the system is 0.006 ppb;the error between the real value and the measured value is less than 5%;the overall variation coefficient of high,medium and low concentrations is less than 2%.