Odor Gas Online Detection Theory And Experiments Research Based On Microfluidic Chip

Along with rapid development of economic and urbanization construction, the odor pollution, ranked as the second complaint event, is increasing to affecting the normal hunman life seriously. “The 12 th five-year plan for national economic and social development program”, therefore, puts forward to strengthen management of odor pollutants. Studing on theory and method is the most urgent problem needing to solve for odor gas online dececting instrument development. Thus, the research mission of this thesis is to provide not only an efficient and real-time odor gas detecting instrument but also the theory and experiment of odor detecting for environmental management departments of our country.With the advantage of high separating efficiency, fast detection, high selectivity, high precision analysis, gas chromatography(GC) technology is widely used in the gas detecting area. Growing of micro-electromechanical system, micro-fluidic chip, and micro fabrication and other emerging technologies promote GC instrument with micro-separator, micro-detector and micro-controller to become the research focus of miniaturization, portable and real-time online detection.After summarizing the development of modern GC and separator, detector or other key technologies of GC instrument in China and abroad, this thesis presents the theory, method and simulation of GC based on micro fluidic chip for a scheme of odor detecting. And the odor online detecting system based on micro fluidic chip is developed for a series of odor gas detecting experiments. This thesis is supported by the national major scientific instruments and equipment development projects for accomplishing “the development and application of odor automatic online monitoring and early warning instrument”.(NO.2012YQxxxxx). The main researches and achievement of this thesis are as follow:1、The model of gas concentration change after sample separation passing through column is established from studying in GC column plate theory and rate theory. With the results of simulating this model by COMSOL Multiphysics, parameters effecting separation efficiency are analyzed for comfirming the way of GC based on micro fluidic chip to be odor separator.2、As the key technique of odor gas online detecting system, the separator is further researched, including material, fabrication method, channel design, choosing of stationary phase and so on. At last, two kinds of micro fluidic chip columns are manufactured. One is micro fluidic chip packed colume, the other is micro fluidic chip capillary column.3、The photo-ionization detector(PID), as the key technicque of odor gas online detecting system, is further studied for meeting trace detection of odor gas. For PID is used as detection unit of system, the development of UV radio-frequency power supply、conditioning circuit of gas concentration signal and design of the PID chamber were achieved.4、Study on the theory and key technique, the scheme of odor gas online detecting system is complished with carrier gas pressure measurement unit, automatic flow control unit; automatic sampling unit; micro fluidic column unit; PID unit; PC controller unit; data collecting and processing unit. The micro controller unit, related software development, the qualitative and quantitate analysis method of odor components are detailed in this thesis.5、With this developing odor online detecting system, we hold series of odor detecting experiments using some different kinds of micro fluidic chip columns. Firstly, the stability and repeatability experiments are held for examining the online system. Further more, odor gases separation and detection experiments with some different columns, including the capillary chromatographic column with different sizes and micro fluidic capillary column with different stationary phase. At last, a series separation and detection experiments is held in different temperature or pressure condition for verifying the effection of environment to this odor online detetcting system.At the last of this thesis, the main research works are summarized. The theoretical method and experimental studies have illustrated feasibility of odor gas online detecting system with separation based on micro-fluidic chip technology. Achievement of this research supplies a new technical method and series experimental data to realize miniaturization, portable, realtime online detection instrument in our country. Inadequate points existed in the system and future improvement methods are also discussed in the end of this thesis.