Determination of Five Sulfonamides in Water by High Performance Liquid Chromatography Combined with Ionic Liquid Liquid-liquid Microextraction

A novel method for the determination of sulfamethazine (SM2), sulfamonomethoxinc (SMM), sulfamethoxazole (SMZ), sulfadiazine (SD), sulfaquinoxaline (SQX) from the water has been developed using ionic liquid dispersive 1iquid-liquid microextraction coupled with high performance liquid chromatography. The influence of extraction parameters including types of extraction solvent, volume of extraction solvent, types of dispersant solvent, volume of dispersant solvent, extraction time, and pH were investigated. Using 80 μL 1-Hexyl-3-methylimidazolium hexafluorophosphate ([C6MIM]PF6) as extraction solvent, 800 μL acetonitrile as dispersant solvent, pH=4.0, extraction 3min, centrifugal after storage 2min. Under the optima1 conditions, good linear relationships were obtained in the five sulfonamides residues concentrations of 5~150 μg•L-2 with the correlation coefficients of 0.9988-0.9994, limits of detection (LOD) were 0.74~1.21 μg•L-2 (S/N=3), limits of quantification (LOQ) were 2.51~4.06 μg•L-2 (S/N=10). The proposed method was applied to the determination of five sulfonamides residues in water, the recoveries were from 88.5% to 98.8%, with the corresponding intra-day RSDs less than 5.1%, inter-day RSDs less than 9.5%. The method was considered to be simple, fast, and precise to satisfy the requirements of the residual analysis of sulfonamides in water.