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

Abstract

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.