The Design Of Gas Separation And Detection Technology Based On Microfluidic Chip

The environmental problems caused by the odor causing serious harm to the global,malodorous gas monitoring is becoming an important part of the environmental monitoring.Gas detector and gas separator are the key component in qualitative and quantitative analysis of the odor gas and the core part of the automatic on-line monitoring instrument.Therefore,developing gas detector and gas separator has great significance.Through checking a large number of literature,the paper summarizes the latest research progress and development direction in the field of gas separation and detection.Based on the theory,gas separation and detection on the basis of microfluidic chip is selected.combined theory research with experimental analysis,the gas separation and detection devices used for gas automatic on-line monitor are developed.The paper introduces the chromatography theory firstly.Combined the microfluidic chip technology with gas chromatography technology,it puts forward a detecting program that uses microfluidic chip as the separator and the photoionization detector as the detector.According to the fluid simulation software COMSOL simulating gas separation in microfluidic chip,the filled microfluidic chip and the capillary microfluidic chip are developed.The channel of the chip is S type and the size is 115×60×6mm.The channel cross section of the filled microfluidic chip is a circular with a diameter of 1mm and the total length is 1.8m.The channel cross section of the capillary microfluidic chip is a circular with a diameter of 0.4mm and the total length is 6m.Both of the channels are made by sand-blasting technology and the chips are bonded by thermal bonding techniques. The channels are coated with different polar stationary phase to detect the separational effect.According to the photoionization theory and characteristics,the UV lamp with 10.6ev and the steel electrode materials are selected.The UV driving circuit and weak signal conditioning circuit are designed.Finally,the response relationship of the detection circuit to the single gas are analyzed and the response curve is fitted.The results show that the detection circuit has good repeatability and accuracy.The experiments test the stability and repeatability,analyze the effect of temperature and pressure on the detection results,research the the separation effect of the same components on different stationary phase.based on the chromatogram analysis,theoretical plate,retention time,half peak width and resolution are calculated.The results show that the detection system can meet the basic requirements of the odor detection.Finally,the paper introduces the shortage in research work and improvement measures,and prospects the development direction in the future research.