采用串联双柱-反吹气相色谱系统测定汽油中苯含量

采用一个有串联双柱-反吹系统的气相色谱仪分析检测汽油中的苯含量。样品组分首先进入一非极性的预切柱按沸点高低顺序分离,通过切换六通阀反吹放空重组分,使辛烷及轻烃组分进入具有强极性的TCEP分析柱,芳烃和非芳烃经分离后进入TCD检测器。该方法确定了最佳阀切换反吹时间和操作条件,以丁酮为内标物,通过建立苯的校正曲线定量计算样品中苯的体积浓度。实验的回收率在93.8%~99.1%,方法的相对标准偏差(RSD)≤2.45%。

Determination of benzene in gasoline by two columns-back flushing gas chromatography

A method for determination of benzene in gasoline by two columns-back flushing GC was studied.The samples which had different boiling points were separated by nonpolar precolumn.With the heavy hydrocarbon flowed out in air,the octane and aromatics entered the TCEP analytical column,then they detected completely by TCD.Working condition of GC system was established perfectly.With the internal standard of butanone,volumetric concentration of benzene was calculated by the calibration curve.The recovery was 93.8%～99.1% and the RSD≤2.45%.