Abstract: Two different sample pretreatment methods, namely the national standard method GB/T 20759－2006 and a method developed in our laboratory were compared for their application in LC-MS/MS determination of sulfonamide residues in hen,s eggs. The average recoveries of the national standard method across the spike levels of 10, 100 ng/g and 200 ng/g ranged from 20.8%－67.7%, which could not meet the requirements. Moreover, the method was not suitable for use in the extraction, concentration, defatting, and standard curve preparation of egg foods. Therefore, the determination of sulfonamide residues in eggs requires a new specialized method due to their special characteristics. The average recoveries of the self-developed method were between 77.92% and 95.26% and could meet the requirements for the determination of sulfonamide residues.

Key words: sulfonamide, hen,s egg, sample pretreatment