Rapid determination of sulfonamides in milk using micellar electrokinetic chromatography with fluorescence detection Original Research Article

A new method was developed for the determination of sulfonamides in milk by using micellar electrokinetic chromatography coupled with fluorescence detection. Separation of fluorescamine-derivatized sulfonamides was accomplished by using a buffer 13.32 mM disodium hydrogen phosphate, 6.67 mM potassium dihydrogen phosphate and 40 mM sodium dodecyl sulphate at pH 7.5 in addition to positive power supply at 21 kV at 25 °C. Detection was performed using UG-11 excitation filter and 495 nm emission filters. The proposed capillary electrophoresis method allows the separation of five sulfonamides within 7 min with a limit of detection of 1.59–7.68 nmol/L for all the sulfonamides considered for present study. A simple sample preparation method with fairly good recoveries 85–114% is also presented in current paper. Inter-day and intra-day validation of the separation method shows fairly good results. Robustness of the method has also been studied.