固定污染源NMHC气相色谱仪安装调试技术重点及“鬼峰”探究

Keys in Installation and Debug of GC Monitoring NMHC from Fixed Pollution Sources and Exploration of Ghost Peak

在环境监测领域,固定污染源非甲烷总烃(NMHC)通常使用气相色谱分离+FID监测器的方法监测。而在气相色谱仪(包括FID检测器)的安装调试过程中,重点要注意气路系统的气密性、流量准确及稳定性。通过探究色谱柱温度与鬼峰的保留时间的关系,对可能形成鬼峰的原因做初步判断,并采用逐个替换气路元件的方法找到鬼峰的产生原因:普通不锈钢管内含的杂质和聚四氟乙烯管路对VOCs的吸附。

In the Field of Environment Monitoring, NMHC from fixed pollution sources is monitored by GC+FID method popularly. In the process of installing and debugging GC, we should pay much attention to gas tightness and accuracy and stability of flow rate. By the exploration of the relationship between the temperature of GC column and ghost peak retention time, the reason could be preliminarily judged, which caused the ghost peak. After replacing the components in gas system one by one, we found that the main factors causing ghost peaks are impurities attaching on the general stainless steel tube and VOCs absorbed by PTFE tube.