Capillary Electrophoresis analysis of gentamicin sulphate with UV detection after pre-capillary derivatization with 1,2-phthalic dicarboxaldehyde andmercaptoacetic acid

A selective, sensitive, and rapid pre-capillary derivatization method for d etermination of the multicomponent aminoglycoside antibiotic gentamicin is described. The derivatization reagents 1,2-phthalic dicarboxaldehyde and me rcaptoacetic acid were used and the thioisoindole derivative was UV detecte d at 330 nm. A central composite experimental design was performed to optim ize selectivity and derivatization conditions. Baseline separation of genta micin C-1, C-1a, C-2, C-2a, C-2b, sisomicin and several minor components wa s achieved with a background electrolyte containing 30 mM sodium tetraborat e, 7.5 mM beta -cyclodextrin and 12.5% (v/v) methanol at pH 10. Quantitativ e analysis was performed and illustrated the potential use of capillary ele ctrophoresis for the identification and quantitation of gentamicin as an al ternative to methods prescribed in the United States Pharmacopeia and Europ ean Pharmacopoeia. (C) 2000 Elsevier Science B.V. All rights reserved.