大气中甲烷、总烃及非甲烷总烃监测分析方法的探索

Discussion on Methane Total Hydrocarbons and Non-Methane Hydrocarbons in Ambient Air Monitoring and Methods of Analysis

摘要: 采用六通阀进样，双毛细管柱、双FID检测器气相色谱法，一次进样即可测得大气中的CH₄、总烃及非甲烷总烃（NMHC）的测试数据。同时对色谱中FID检测器中出现的氧峰初步可认定为“干扰峰”，在分析中可忽略不计。方法的检出限：CH₄ 0.03 mg/m³，总烃0.04 mg/m³，NMHC 0.06 mg/m³。变异系数：CH₄ 3.81%，总烃 2.07%，NHMC 5.07%。

Abstract: Methane (CH₄) and non-methane total hydrocarbons (NMHC) in gas samples are analyzed simultaneously by gas chromatography. A six-way valve to inject the sample, double capillary columns, and double FIDs are used. With one injection the analytical data of CH₄, total hydrocarbons, and non-methane total hydrocarbons can be obtained. A reasonable explanation for the oxygen peak appeared in the GC with FID detector is given, which can be preliminary identified as"the interference peak", and can be negligible in the analysis. The method detection limit of CH₄, total hydrocarbons, NMHC were 0.03 mg/m³, 0.04 mg/m³ and 0.06 mg/m³. The coefficients of variation of CH₄, total hydrocarbons, NMHC were 3.81%, 2.07% and 5.07%. The recoveries of spiked compounds of CH₄, NHMC were 96.1%, 96.1%~ 98%.