氢火焰离子化检测器电子线路设计

发布时间：2018-06-25 05:03

本文选题：气相色谱 + 对数运放　；参考：《西安电子科技大学》2015年硕士论文

【摘要】：近年来,氢火焰离子化检测器(FID)在气相色谱领域应用越来越广,FID具有很多优异特性,在检测器领域中具有良好的应用前景。本文作者在江苏天瑞仪器实习的过程中对FID的各个功能模块进行了系统的研究,包括信号采集部分、高压模块设计及点火电路。本文首先针对FID在气相色谱质谱联用仪上的具体应用提出了一些使用和操作上的注意事项。通过对电极形状和喷嘴内径及材料的选择可以提高它的灵敏性。此外,我们可以通过其结构和操作两方面的因素来提高有机物的离子化程度和集电极对离子的收集效率。在信号采集部分,基于原来采用的比例运放,我们引入了对数运放的思想。对数放大器兼具线性性质和信号放大特性,避免了比例运放要根据出峰情况手动调整放大倍数的缺陷。最后针对FID中的实际信号采集放大电路进行了仿真,仿真之后得到的结论和理论上推倒的数值基本吻合。对于加在离子室集电极的高压,我们利用电容二极管倍压电路设计实现了300V的高压。首先对倍压原理进行了详细阐述,然后对FID高压电路进行了Multisim电路仿真。最后我们利用开关电源控制点火丝上的电流,使其达到了自动点火的功能。通过对开关电源BUCK电路的深入理解和总结,设计了输出滤波电感和电容值,最终实现了点火丝上的额定电流输出。
[Abstract]:In recent years, hydrogen flame ionization detector (FID) has been widely used in the field of gas chromatography. During the practice of Tianrui instrument in Jiangsu province, the author has carried on the systematic research to each function module of FID, including the signal collection part, the design of high voltage module and ignition circuit. In this paper, the application of FID in gas chromatography-mass spectrometer is discussed. The sensitivity can be improved by selecting the electrode shape, nozzle inner diameter and material. In addition, we can improve the degree of ionization of organic compounds and the efficiency of collecting ions by the structure and operation of organic compounds. In the part of signal acquisition, based on the original proportional operational amplifier, we introduce the idea of logarithmic operational amplifier. The logarithmic amplifier has both linear property and signal amplification property, which avoids the defect that proportional operational amplifier should manually adjust the magnification according to the peak condition. Finally, the actual signal acquisition and amplification circuit in FID is simulated, and the simulation results are in good agreement with the theoretical values. For the high voltage of ion chamber collector, a 300V high voltage is designed by using capacitive diode voltage doubling circuit. Firstly, the principle of voltage doubling is described in detail, and then the simulation of FID high voltage circuit based on Multisim is carried out. Finally, the switch power supply is used to control the current on the ignition wire, which makes it achieve the function of automatic ignition. Through the deep understanding and summary of the buck circuit of switching power supply, the output filter inductance and capacitance are designed, and the rated current output on the igniter wire is finally realized.
【学位授予单位】：西安电子科技大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TH83;TN702

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