Abstract:

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 50000 mg/L. The linear correlation coefficients (r²) for ethyl acetate, sec-butyl acetate and dimethyl carbonate were 0.99999, 1.00000 and 0.99995, 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 efficient, and can be used as an ideal method for the analysis of the ester compounds in gasoline.

Key words: sec-butyl acetate, dimethyl carbonate, ethyl acetate, gasoline, two-dimensional gas chromatography