Fluorescence detection and identification of eight sulphonamides using capillary electrophoresis on released excipients in lake water

A simple and sensitive capillary electrophoresis method with fluorescence detection was developed for the determination of sulphanilamide, sulphamerazine, sulphacetamide and sulphanilic acid, sulphathiazole, Sulphisomidine, sulphadoxine and sulphadiazine in lake water. The sulphonamides were extracted from lake water, derivatized with fluorescamine and determination of sulphonamide was achieved using 20 mM borate buffer of pH 9.5 at an applied voltage of 25 kV. Detection was performed using UG-11 excitation filter of 405 nm and 495 nm emission filters. A fast, simple and sensitive method with limit of detection in the range 0.89–1.43 n mol L⁻¹ for all the eight sulphonamides with good recoveries of 80–110% is seen. Inter-day and intra-day validation of the separation method shows fairly good results. The detection and quantification limits for this newly developed method are too low to determine drug residues in lake water.