Research On The Key Technology Of Microfluidic Chip For Gas Detection

Malodorous gases have been widely concerned, but it is difficult to be collectedand detected.So a portable and online detection instrument which can measure themalodorous gases accurately is in great need. This paper is based on two theories,one is gas chromatography and the other is microfluidic chip technology.The formerhas been considerably developed from the last century, and regarded as a primarymeans of gas detection. But the chromatograph`s volume is too huge to achievereal-time detection in application region.The development of microfluidic chiptechnology thanks to the advanced processing of MEMS technology. Theoretically,by using MEMs Technology,most of the main components of the gas chromatographcan be etched into a several square centimeter chip. So the microfluidic chip is a goodchoice to make the gas instrument more portable.Even a lot of institutions around theworld is woking on this technology,but barely achieve commercialization at present.The gas separation system of gas chromatograph (i.e. the chromatographiccolumn and the temperature box) account for about half of the volume ofchromatograph, therefore reduce the separation system volume is very important.Inthis paper, with combining these two technologies,I have designed a microfluidicchip which is can be used in portable instrument:(1) one microfluidic chip is a packedcolumn made by sand blasting process, the channel shape is S-type,the innerdiameter of the column is1mm, and the long is1.8m.The whole volume of the chip is115×60×6mm3(2) the other chip is made by wet etching technique.The chip section isa rectangular,the side longth is0.15mm and the channel length is0.75m.The wholevolume of the chip is40×12×0.9mm3.According to the need of malodorous gasesdetection, this paper chose polyethylene glycol as stationary phase.Then complete thecoating of microfluidic packed column and the micro fluidic capillary column.Thechromatographic analysis requires excellent sealing performance, so this projectdesigns a variety of chip interface schemes, and at last we selected two of theschemes using for our system.This paper also designed the chip separation that ishaving significant impact on the column pressure system.Finally, we complete the design of column pressure system, and the chip application test. Results show thatthe chip has a very high number of theoretical plate(2156).The research has achieved the desired objectives and fabricated the microfluidicchromatography system for portable instruments.But to make super small instrumentsalso need to integrat the sample gas chromatograph system and the detection systemon a chip. In addition, the chip can also integrat a heating layer to heat the chipdirectly to acheive a higher heating efficiency than the air bath heating.This is thekey torapiddetection.The next task is to carry out such studies.