Development Of A Novel Plasma Ionization Detector For Gas Charomatography

Gas chromatography is an important technique for separation and analysis, with rapidity, high efficiency, high sensitivity, and good selectivity. It has been widely applied to the determination of pollutants in environmental samples, oil and natural gas composition analysis, determination of pesticide residue in food, medicine analysis, etc. The development of gas chromatography depends largely on the detector development, and the plasma ionization detector is one of the important developments with respect to gas chromatographic detectors. Plasma can make the sample evaporation, atomization, excitation and ionization. Since late in 1950s, the use of gas plasma as a gas chromatographic detector has attracted more and more attention.The details of the principle, construction, and application of a He-DCPID are presented in this study. The main contents of the dissertation are as follows:1. The principle, applications and development of gas chromatography are briefly introduced. The principles, advantages and disadvantages of the traditional GC detectors are critically reviewed.2. The development of the plasma detectors for gas chromatography are reviewed in this dissertation. The principle, construction, applications, advantages and disadvantages of these detectors are summarized systemically.3. A novel direct current plasma ionization detector (DCPID) was developed. The principle and structure of the detector are described in detail. The key point is concentrated onto the design of the hardware and software flowchart of the temperature control system.4. Optimization of the parameters of the detector was carried out, and a good reference value for the practical application was provided. The common components of some natural gas samples were analyzed with this detector and the performance of the detector for determination of some organic and inorganic components were evaluated. It was shown that the detection limits for inorganic gases can reach the level of 10-9g/s, and the detection limits for common organic compounds can reach the level of 10-10g/s. The detector is simple in structure, convenient in operation with good versatility.5. Summary and prospective.