LIN Lin, ZHANG Qi-chun, YE Jian-feng
(Environmental Monitoring Station of Longgang District, Shenzhen 518172, China)
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%.
Key words:double capillary columns;double FIDs;methane;total hydrocarbons;non-methane total hydrocarbons ( NMHC )
Analysis and Testing Technology and Instruments, Vol. 18, No. 4, 2012,217-221