Research Of The Gas Sensor Technology Based On The Microfluidic Chip

With the odor pollution is worsening,strengthen the odorous gas monitoring is becoming an important content of environmental monitoring,and achieving the detection of trace composition and concentration of odorous gas is the key to the odor governance.The current odor monitoring equipments are expensive and bulky,and the sensors have poor gas selectivity,so that they are unable to meet the needs of practical applications.Therefore,the development of a gas sensor which can detect the gas component and concentration will effectively meet the demand of environmental gas monitoring.In order to achieve this goal,this paper has put forward a single gas sensitive sensor combined the technology of gas separation and gas sensor.The research has important theoretical significance and practical value.Firstly,this paper summarizes the latest progress in the field of gas detection and the latest application of microfluidic chip technology,and then through the analysis and comparison of existing sensor technology,we have studied the theory of photoionization detection,and integrate it into microfluidic chip with gas separation functions so as to develop a kind of a single gas sensitive sensor combined gas separation and detection.According to the research of photoionization theory,the paper chooses the UV lamp of 10.6 eV as ionization source.In the structure: we design and develop the ionization chamber with low interference and fast response,and complete the related structure design of the detector.In the hardware circuit: according to the drivering principle of the UV lamp,we develop a 600 V ac high voltage driving circuit,and complete the development of weak signal conditioning circuit.Through experiments prove,the circuit can realize the pA-level current amplification,and has good linearity.The paper has carried on an exploratory study on the development of microfluidic chip and its integration with photoionization detector.Firstly,based on the chromatographic theory,the paper has made a simulation experiment on the process of microfluidic chip separating mixed gas,and realizes the development of filled and capillary microfluidic chip;Finally,through the research of the existing integration technology,this paper identifies the electroless plating method for preparing microelectrodes on the chip as well as the adhesion method for fixing the UV lamp on a chip to achieve the integration of chip and detector.On the basis,the paper has test the stability and repeatability on the development of photoionization detector,tand he results show that the detector has good stability and the single gas repeat accuracy of 4.8%;Through conducting the research on the influence of temperature and pressure on the test results,we make sure the best experimental conditions for the detection of ethanol-toluene hybrid odorous gas.Finally,the paper describes the shortcomings and improved measures in the research work,and discusses the development direction in the future research.