IDENTIFICATION AND SEPARATION OF 5 CEPHALOSPORINS BY MICELLAR ELECTROKINETIC CAPILLARY CHROMATOGRAPHY

The cephalosporins are a group of structurally related, broad spectrum beta-lactam antibiotics isolated from the mold Cephalosporium. Method s of analysis of cephalosporin antibiotics include microbiological, ti trimetric and chromatographic assays. Chromatographic techniques, incl uding high-performance liquid chromatography, have been extensively ut ilized for specific and sensitive assays of beta-lactam antibiotics in a variety of matrices, i.e. clinical and pharmaceutical. Several of t he drawbacks of HPLC in the analysis of cephalosporins in food and bio logical samples include matrix interferences and low resolution due to column adsorption. Recently, the applicability of capillary electroph oresis to the resolution of beta-lactam antibiotics has been demonstra ted in the literature. In this paper we employed sodium berate and an anionic surfactant, sodium dodecyl sulfate (SDS), in a separation tech nique called micellar electrokinetic capillary chromatography with UV detection, to resolve a mixture of five cephalosporins-cefuroxime, cep halexin, cephapirin, cefamandole nafate and cephalothin. The presence of SDS in the running buffer above the critical micelle concentration, creates a pseudostationary phase enabling high-efficiency chromatogra phic separations. The effect of the ion-pairing reagent, pentanesulfon ic acid sodium salt, on the resolution of the cephalosporin mixture in conjunction with SDS was also examined.