二维中心切割气相色谱法测定汽油中芳烃含量

Determination of aromatics in gasoline by two-dimensional heart-cutting gas chromatography

利用二维中心切割气相色谱的原理和切换、反吹技术,将预柱(TCEP)中的待测组分切换到毛细管柱(SE-30)中,建立了汽油中苯、甲苯、C8和C8以上芳烃含量的检测方法。在第一次分析的进样状态下,在待测物质苯从预柱中流出之前,将六通阀切换到反吹状态,这样待测物质苯,甲苯等极性组分被切换至非极性的SE-30毛细管色谱柱中进行分析。在第二次分析的进样状态下,在乙苯流出之前立即将六通阀切换到反吹状态,TCEP柱中的保留组分进入分析柱中进行分析。采用氢火焰离子化检测器(FID),内标法定量,在检测范围内苯,甲苯,邻二甲苯,1,2,4-三甲苯线性关系良好,相关系数(r2)分别为0.9964,0.9981,0.9988和0.9989,对标样进行6次重复实验,相对标准偏差(RSD)都小于2%。

Determination of benzene, toluene, Cs and the above of C8 aromatics in gasoline was established based on the principle of two-dimensional heart-cutting gas chromatography and the switching, back flushing technique. The analytes were cut from pre-column （TCEP） to capillary column （SE - 30）. In the first analysis of the injection state, the 6-port switching valve was switched to the backfluh state before the outflow of benzene from pre-column, so that the analytes including benzene, toluene and other polar components were switched to non-polar SE -30 capillary columns for analysis. In the second analysis of the injection state, the 6-port switching valve was switched to the baekfluh state immediately before the outflow of ethylbenzene from the pre-column . The retention components of TCEP column were switched to analytical column for analysis. FID and internal standard method were applied to the quantitative analysis. The results showed that the four compounds had good linear relationship in the detection range with the correlation coefficient of 0. 9964,0. 9981,0. 9988 and 0. 9989, and the relative standard deviation was less than 2.0%.