Abstract: Taking Glycyrrhiza uralensis as the research object, gas chromatography was used to purify samples by the sulphonation method and QuEChERS method, and the two purification methods were evaluated. The results showed that the impurities in the samples prepared by the two purification methods had no interference to the determination of 9 organochlorines, the treatment effect of QuEChERS was better and the impurities were less. In the comparative study, the results of repeatability, recovery rate and detection limit showed that QuEChERS method was slightly better than the sulfonation method. QuEChERS method had the advantages of simple operation and few steps. It could be used as a purification method for the determination of pesticide residues in licorice samples, which was exclusive, rapid, sensitive and accurate.

Key words: organochlorine pesticides, Glycyrrhiza uralensis, purification method, QuEChERS method