Dispersive liquid-liquid microextraction coupled with capillary electrophoresis for simultaneous determination of sulfonamides with the aid of experimental design.

A novel method for the simultaneous determination of sulfonamides (SAs) in water samples has been developed by using dispersive liquid-liquid microextraction (DLLME) coupled with CE. Orthogonal and Box-Behnken designs were employed together to assist the optimization of DLLME parameters, including volumes of extraction and disperser solvents, ionic strength, extraction time, and centrifugation time and speed as variable factors. Under the optimum extraction and detection conditions, successful separation of the five SAs was achieved within 5 min, and excellent analytical performances were attained, such as good linear relationships (R>0.980) between peak area and concentration for each SA from 0.5 to 50 μg/mL, low limits of detection for the five SAs between 0.020 and 0.570 μg/mL and the intra-day precisions of migration time below 0.80%. The method recoveries obtained at fortified 10 μg/mL for three water samples ranged from 53.6 to 94.0% with precisions of 1.23-5.60%. The proposed method proved highly sensitive and selective, rapid, convenient and cost-effective, showing great potential for the simultaneous determination of SAs in water samples.