用于测定汽油中甲基苯胺类化合物含量的气相色谱-质谱法

DETERMINATION OF METHYL ANILINE COMPOUNDS IN GASOLINE BY GC-MS

建立了气相色谱-质谱法测定汽油中甲基苯胺类化合物(包括N-甲基苯胺、对甲基苯胺、邻甲基苯胺、间甲基苯胺、N,N-二甲基苯胺)含量的方法。采用酸提取技术,经毛细管色谱柱分离,以气相色谱-质谱选择离子方式(SIM,m/z=107,120)进行外标法定量。通过实验,对前处理条件中萃取剂的浓度以及毛细管色谱柱的类型进行优化。结果表明:以10%(φ)盐酸溶液为萃取剂,采用DB-1MS(30m×0.25mm×0.25mμ)毛细管柱分离,在100～300mg/L的质量浓度范围内,加标回收率为85%～103%;重现性试验的相对标准偏差均不大于2.5%;当信噪比为3时,甲基苯胺类化合物的检出下限为1.0mg/L。该方法准确、重现性好、检出下限低。

A gas chromatography-mass spectrometric （GC-MS） method was developed for the determination of methyl aniline compounds （including N-methyl aniline, p-methyl aniline, o-methyl aniline, m-methyl aniline, N,N-dimethyl aniline） in gasoline. The methyl aniline compounds were liquid-liquid extracted with acid and separated by capillary chromatographic column, the qualitative measurements were conducted with selected ion monitoring mode（m/z-= 107,120）and then quantified with external standard method. The concentration of extractant in sample pretreatment and the type of capillary column used were optimized. It is concluded that using hydrochloric acid solution with volume fraction of 10% as extractant, separating by DB-1MS （30 m×0.25 mm×0. 25 μm） capillary column, with methyl aniline compounds concentration in the range of 100-300 mg/L, the recoveries of standard addition are in the range of 85%-103%. The relative standard deviations of reproducibility tests are not more than 2. 5% and the detection limit is 1.0 mg/L when SNR （signal to noise ratio） is established as 3. This method is accurate, with good reproducibility and low detection limit.