二维气相色谱技术分析汽油中的3种酯类化合物

Determination of three ester compounds in gasoline bytwo-dimensional gas chromatography

建立了一种采用填充柱切割-反吹二维气相色谱分析汽油中酯类化合物（包括乙酸乙酯、乙酸仲丁酯、碳酸二甲酯）的方法。利用非极性填充预柱将汽油中沸点低于正辛烷的轻组分保留进入分析柱，重组分反吹放空，轻组分和酯类化合物经一个装填有强极性固定相的色谱柱分离分析。采用外标法定量，3种酯类化合物在50~50000 mg / L 范围内线性关系良好，相关系数（r2）分别为0.99999、1.00000和0.99995，标准样品6次重复性测定的相对标准偏差（RSD）均小于1.0％，回收率在98.7％~107.9％之间，方法检出限（ S / N ＝3）为5 mg / L。该方法不需要进行样品前处理，具有操作简单，准确高效的特点，是汽油中酯类化合物测定的理想分析方法。

A simple and efficient method based on the technique of packed column switching-back flushing was established for the analysis of the ester compounds（including ethyl acetate, sec-butyl acetate,dimethyl carbonate）in gasoline. With the use of a non-polar pre-column,we successfully separated the components in gasoline by back flushing out components heavier than n-octane,while the lighter components and the ester compounds were flushed into a polar analytical column. In this method,external standard method was applied for quantification. As a result,good linear relationships existed among the three ester compounds in the range of 50 mg / L to 50 000 mg / L. The linear correlation coefficients（ r 2 ）for ethyl acetate,sec-butyl ace-tate and dimethyl carbonate were 0. 999 99,1. 000 00 and 0. 999 95,respectively. The relative standard deviations（RSDs）of standard samples in six continuous tests were within 1. 0% . The recoveries were between 98. 7% and 107. 9% . The detection limit of the method（S / N = 3）was 5 mg / L. No pretreatment was needed. This method is simple,accurate,quick as well as effi-cient,and can be used as an ideal method for the analysis of the ester compounds in gasoline.