The qualitative screening and the quantitative analysis of the three unconventional additives for motor gasoline,namely methylal,dimethyl carbonate and N-methyl aniline,were researched by gas chromatography-mass spectrometry method.The qualitative analysis was carried out by total ion scanning,contrasting the retention times and the characteristic ion mass spectra of the standard substances.And the quantitative analysis was conducted by a characteristic ion procedure combined with an internal standard method.The effects of the gasoline background on the qualitative analysis and quantitative analysis were investigated.The results showed that the recoveries of the three compounds were in the range of 95.83％-101.11％ and the relative standard deviations were less than 5％.The detection limits of methylal,dimethyl carbonate and N-methyl aniline were 0.01％(w),0.01％(w) and 0.1％(w),respectively.The repeatability of the method can meet the requirement of routine analysis.%采用GC-MS联用法,对车用汽油中含有的非常规添加物甲缩醛、碳酸二甲酯和N-甲基苯胺进行了定性筛查和定量检测.其中,定性分析采用全离子扫描、与标准物质保留时间对照及与标准物质的特征离子图对比等方法；定量分析采用特征定量离子提取结合内标法.同时考察了汽油本底对这3种化合物定性检测和定量测定的影响.实验结果表明,3种化合物的回收率在95.83％～ 101.11％之间,相对标准偏差小于5％,定量数据准确可靠；各组分含量在2％(w)以内,线性响应良好；甲缩醛和碳酸二甲酯的检测限为0.01％(w),N-甲基苯胺的检测限为0.1％(w).该方法重复性和再现性均能满足常规分析要求.
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