罐采样-加压进样-气相色谱法测定环境空气中非甲烷总烃研究

Study on Determination of Non-methane Total Hydrocarbons in Ambient Air by Canister Sampling-Pressure Sampling-Gas Chromatography

建立了罐采样-气相色谱法测定环境空气中非甲烷总烃的分析方法。用罐采集环境空气样品至微负压状态,经除烃空气加压后,用气相色谱仪进行分析。并对氮气空白、除烃空气、样品保存期限、不同压力进样、不同正压压力进样、不同湿度、不同种类物质对总烃的贡献等进行了研究,在最佳实验条件下,非甲烷总烃的方法检出限为0.04μmol/mol,标准曲线相关系数均大于0.999 5,低、中、高浓度水平测定结果相对标准偏差均小于2.0%,低、中、高浓度的质控样品相对误差均小于2.0%。利用该方法对环境空气样品进行了检测分析,该法完全满足国家标准质控的要求,适用于环境空气和污染源无组织废气中非甲烷总烃的准确测定。

An analytical method for the determination of non-methane total hydrocarbons in ambient air by canister sampling-gas chromatography was established.Ambient air samples were collected in a tank to a slightly negative pressure state,and after being pressurized by dehydrocarbon air,they were analyzed by a gas chromatograph.The nitrogen blank,dehydrocarbon air,sample shelf life,injection at different pressures,injection at different positive pressures,different humidity,and the contribution of different substances to total hydrocarbons were studied.Under the best experimental conditions,the detection limit of the method for non-methane total hydrocarbons was 0.04 μmol/mol,the correlation coefficient of the standard curve was all greater than 0.9995,the relative standard deviation of the determination results of low,medium and high concentration levels were all less than 2.0%,and the relative error of the quality control samples of low,medium and high concentration were all less than 2.0%.This method was used to detect and analyze the ambient air samples.The method fully meets the requirements of national standard quality control,and is suitable for the accurate determination of non-methane total hydrocarbons in ambient air and unorganized waste gas from pollution sources.