Abstract: A method for determining chlorine content in gasoline by X-ray fluorescence analysis is introduced. At the best conditions of 25 kV and 1.0 mA, the chloride concentration in the range of 10-1 000 ug/g is linear with the fluorescence intensity. The influence of different substrates （mixture of petroleum ether and toluene (a valume ratio of 6:4 v/v), isooctane and commercially available chlorine standard sample）on the results of determination is studied, and their standard curves were established, respectively. It is found that the isooctane is the best substrate for the method. Precision and repeatability of the method were investigated. The effect of different gasoline and samples with different chlorine forms was invested. The results show that the recovery rate is between 95% and 105%, and the relative standard deviation is less than 4.2%.

Key words: X- ray fluorescence spectrometry, chlorine content, gasoline, substrate