气相色谱仪电子捕获检测器的清洗方法

Cleaning methods of electron capture detector for gas chromatographer

气相色谱仪电子捕获检测器是一个有选择性的高灵敏度的检测器,已成为目前在食品检验、动植物体中的农药残留量和环境检测领域中应用最多的检测器之一。电子捕获检测器对杂质十分敏感,放射源表面污染时,使放射源电离能力下降,从而使直流电压和恒频率方式的检测器基流下降或恒电流方式的检测器基频增高;另外,杂质可以直接俘获检测器中的电子,使基流下降或基频增高;两者最终均导致灵敏度降低。本研究总结了电子捕获检测器的清洗方法,氮气热清洗检测器可以除去轻微的化学污染;在室温条件下,甲醇清洗检测器可以除去石墨碎屑、色谱柱碎末;在检测条件下使用甲醇热清洗检测器可以降低噪音。

Electron capture detector of gas chromatograph is a selective and highly sensitive detector,which has become one of the most widely used detectors in the fields of food inspection,pesticide residues and environmental detection.The electron capture detector is very sensitive to impurities.When the surface of the radioactive source is polluted,the ionizing capacity of the radioactive source is reduced,which makes the detector base current of DC voltage and constant frequency drop or detector base frequency of constant current increase.In addition,impurities can capture electrons directly in the detector,making the base flow drop or the base frequency increase.Both of them eventually lead to a decrease in sensitivity.This paper summarized the cleaning methods of electron capture detector.Nitrogen thermal cleaning detector can remove slight chemical contamination.At room temperature,methanol cleaning detector can remove graphite fragments and chromatographic column fragments.Under test conditions,heat cleaning the detector with methanol can reduce noise.