Electrophoretically mediated microanalysis of gentamicin with in-capillaryderivatization and UV detection

This paper describes a system for integration of a one-step-microscale chem ical derivatization and analysis by a methodology known as electrophoretica lly mediated microanalysis (EMMA). Differential electrophoretic mobility be tween an analyte, reagent, and their product offers EMMA a unique capabilit y to selectively carry out electrophoretic mixing, control product formatio n, and separation. This system was successfully applied to perform derivati zation and separation of the multicomponent aminoglycoside antibiotic genta micin using 1,2-phthalic dicarboxaldehyde and mercaptoacetic acid as labeli ng reagents. A multivariate approach based on central composite experimenta l design was used to optimize the derivative yield. Full automation of the derivatization and analytical procedure, high derivatization efficiency, hi gh Sample throughput, and precision are the excellent features of the prese nt method. in addition, this methodology offers short analysis time, as wel l as selectivity and sensitivity suitable for impurities determination. Sep aration of gentamicin C-1, C-1a, C-2, C-2a, C-2b, sisomicin, and several mi nor components was achieved. For the first time separation and identificati on of three impurities, namely garamine, 2-deoxystreptamine, and paromamine are described.