The Development Of The Key Circuit Of The Rapid Detection Instrument For Small Harmful Heavy Metal Elements

The rapid development of the global economy and the rapid growth of the population,resulting in the deterioration of the human living environment.In this day of environmental pollution,food safety,water safety "fear" of the times,people's living environment is also increasingly harsh,harmful hazards of heavy metals is closely related to the study and has become an important topic of great concern and research.In this subject,the harmful heavy metal pollution widely concerned at present(As,Pb,Ge,Hg)as the starting point,the three aspects of the existing instrument volume,the detection accuracy and detection efficiency,the element lamp current pulse drive,fluorescence signal detection,dual channel detection points when the three key technology further research,successfully developed a hydridebased onthe generation atomic fluorescence spectrometry combined use of miniaturized analysis technology of rapid detection of harmful heavy metals,for the detection of environmental pollution,food safety,water safety,clinical medicine,drug safety and other harmful heavy metals analysis field,to provide practical solutions for efficient,heavy metal decision analysis and research of various sectors of society to be more effective and accurate guarantee.This research is supported by the national major scientific research equipment development(41227802)and the young and middle-aged backbone teacher training program(KYGG201513)of Chengdu University of Technology,These following specific research have been done:(a)Research on power supply technology of high performance hollow cathode lamp.In depth study of the principle of atomic fluorescence excitation of high performance cathode lamp,the parameters and characteristics of the important components such as hollow cathode lamp,lens and negative high-voltage transformer are studied.On the one hand,the increase of hollow cathode lamp irradiation intensity,enhanced atomic fluorescence intensity of the target elements at the same time,reduce the atomic fluorescence intensity of remaining interference elements,improve the SNR and enhance detection accuracy and reliability of the instrument;on the other hand,the use of strength and reduce the average power consumption of high performance hollow cathode lamp,significantly prolong the service life of the lamp,improve the service life of the instrument;(b)Research on atomic fluorescence signal acquisition technology.On the method of atomic fluorescence signal acquisition,selecting the appropriate detector,atomic fluorescence signal acquisition target elements,and the design of signal amplifier circuit,the measuring element content will be converted into a number of signal size linearly related,as much as possible to remove the noise in the signal and improve the SNR,improve the precision of the instrument and reduce the detection limit of element content;(c)Research on dual channel time division detection of two elements.The excitation condition further research target elements strongest atomic fluorescence,time interleaved on two kinds of hollow cathode lamp of different driving,exist simultaneously in the atomic fluorescence interference elements and another target elements under the condition of using single detector signal acquisition atomic fluorescence corresponding to the target element,effective atomic fluorescence signal current the target element.From the begingof research work to the development of the instrument,these achievements have been abtained as follows:(a)Instrument developing.Complete the development of the hardware circuit design and control program of the instrument,improve the performance index,performance index test instrument: correlation of up to 0.9998,the lowest detection limit can reach 0.004ng/mL single channel,dual channel can reach 0.15ng/mL,the reproducibility is better than 0.5%.The test results show that the performance of the instrument has reached or even exceeded the expected target,The main technical indicators have reached or exceeded the domestic similar products;(b)Detection efficiency.The performance of the instrument has been improved,aswellas the detection efficiency of the instrument.The measurement time of single channel or dual channel is below 28s;(c)Miniaturization.The off-line integrated control module complete the measurement process control and data processing and analysis function,abandon bulky computer,greatly reduced the instrument volume,expandthe extensive applications of instrument.The innovation of the research is mainly manifested in the following aspects:(a)In a typical architecture based HG-AFS analysis instrument,optimize the design of key components of the feed system,hydride generator,gas control unit,preamplifier circuit,successfully solved the mercury "residual effect",further reduce the mercury detection limit,effectively improve the reproducibility at the same time;(b)Off-line control module has been adapted to replace the computer,the measurement process control and data processing functions are integrated into the microcontroller,greatly reducing the volume of the instrument,making the application of the instrument more widely;This study is based on the basic structure of the HG-AFS analysis method,focus on these three key technologies of equipment manufacturing process,in order to improve the detection performance of index instrument,and reduced the instrument volume,improve the detection efficiency.Contributesome strength in improving the instrument detection performance and expanding the application places.