Determination of Sulfonamides in Milk by Cloud Point-Salting Out Extraction and Ultra-High-Performance Liquid Chromatography Tandem Mass Spectrometry

A method involving cloud point-salting out extraction (CPSOE) coupled with UHPLC-MS/MS was developed for the determination of eleven sulfonamides in milk. In this study, the type and concentration of the surfactant, de-emulsification condition, pH value, volume of n -butanol, equilibration temperature and time were optimized. For this developed method, the linear range of SAs was from 0.05 to 50 µg L –1 , and the correlation coefficients were higher than 0.997. The average recoveries for SAs were from 61.32 to 91.67%, and the LOQs were less than 0.06 µg kg –1 .