Microextraction of sulfathiazole from milk and honey samples using a polymeric ionic liquid membrane followed by fluorometric determination

Abstract

A novel and sensitive method for the determination of sulfathiazole (STZ) in milk and honey samples is developed. The method is based on solid phase microextraction and preconcentration of the analyte by a poly (ionic liquid) membrane sorbent followed by molecular spectrofluorometric determination using copper nanoclusters (Cu NCs). The membrane sorbent was synthesized via copolymerization of 1-hexyl-3-vinylimidazolium bromide (HVImBr) ionic liquid and methylmethacrylate (MMA) monomers. The determination of the desorbed sulfathiazole was carried out by fluorescence quenching of Cu NCs. The strong interaction between sulfathiazole and copper cluster leading to the use of Cu NCs as a fluorescent probe to detect STZ. Two series of Box-Behnken designs were performed to identify the optimal conditions in sorption and desorption steps. Under the optimum conditions, the linear concentration range was obtained from 0.13 to 25.5 μg mL− 1 with limits of detection and quantification at 0.07 μg mL− 1 and 0.23 μg mL− 1 , respectively. The repeatability for five replicate determinations of 12.8 μg mL− 1 STZ was 2.2 %. The developed analytical procedure was applied for the determination of STZ in milk and honey samples and recoveries were in the range of 84.5–104. % and 96.6–107 %, respectively.