气相色谱法测定汽油中醇醚的含量

Study on Determination of Alcohols and Ethers in Gasoline by Gas Chromatography

气相色谱法测定汽油中醇醚含量近年来被广泛关注,本文采用柱切换-反吹气相色谱技术检测汽油中醇醚含量。该方法利用极性微填充TCEP柱将低沸点的非极性组分从高沸点的极性组分中预分离,放空极性小和易挥发性组分,然后通过切换阀将捕集在TCEP柱中的极性组分和高沸点组分反吹至非极性WCOT柱,按照沸点顺序进行分离。甲基叔戊基醚(MTBE)从非极性柱流出后,切换阀,反吹WCOT柱中保留的重烃组分,作为未分离的峰至检测器检测,在最后一次反吹中,通过电子压力控制(EPC)用于TCEP柱的快速反吹,在15 min内可实现汽油中可能存在的12中醇醚类含氧化合物的分析。实验结果表明,回收率在92.9%~113.0%之间,相对标准偏差(RSD)≤0.55%。

The detection of alcohols and ethers in gasoline by gas chromatography has been widely researched in recent years. A method based on the column switching-back flushing gas chromatography technique was developed for detection of alcohols and ethers in gasoline. One polar micro-packed TCEP column was used to pre-separate the non-polar components with low boiling point from the polar components with high boiling point, and the non-polar and volatile components were evacuated. Then the polar components and high-boiling components captured in the TCEP column were blown to the non-polar WCOT column by the switching valve, and the separation was carried out according to the sequence of boiling point. After the MTBE flowed out from the non-polar column, switching the valve, and the heavy hydrocarbon components retained in WCOT column as unseparated peak was blown to detector. In the last back flushing, the electronic pressure control (EPC) was used for the rapid back flushing of TCEP column, and the detection of 12 kinds of alcohols and ethers oxygenated compounds that may exist in gasoline could be realized within 15 min. The result showed that the recovery was between 92.9% and 113.0%, and the RSD was less than 0.55%.