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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%。
Using the principle of two-dimensional central cutting gas chromatography and switching and backflushing technology, the components to be detected in the pre-column (TCEP) were switched to the capillary column (SE-30) to establish the benzene, toluene, C8 and C8 Above detection method of aromatic content. In the first analysis of the injection state, before the benzene to be tested out of the pre-column, the six-way valve is switched to the state of backflush, so that the test substance benzene, toluene and other polar components are switched to non-polar SE-30 capillary column for analysis. In the second analysis of injection conditions, the six-way valve was switched to the blowback state immediately prior to the ethylbenzene outflow, and the remaining components of the TCEP column entered the analytical column for analysis. The hydrogen flame ionization detector (FID) was used to determine the content of benzene, toluene, o-xylene and 1,2,4-trimethylbenzene in the detection range. The correlation coefficients (r2) were 0.9964 and 0.9981 , 0.9988 and 0.9989. The repeats of six replicates of the standard were all less than 2% relative standard deviation (RSD).