DETERMINATION OF L-GLUTAMATE AND L-GLUTAMINE IN PHARMACEUTICAL FORMULATIONS BY AMPEROMETRIC L-GLUTAMATE OXIDASE BASED ENZYME SENSORS

An amperometric biosensor for the direct determination of L-glutamate was developed by chemical bonding of L-glutamate oxidase (GAO) on a ca rboxylic Nylon membrane with polyazetidine prepolymer (PAP), and using a hydrogen peroxide electrode as indicating sensor. The biosensor is specific for L-glutamate and the peculiar analytical properties (linea rity range, reproducibility, accuracy) were experimentally determined. Furthermore, the same basic biosensor was also modified to be used an d characterized for the direct determination of L-glutamine. This L-gl utamine biosensor was obtained by coimmobilizing, on two separate memb ranes, glutamic acid oxidase and glutaminase (GMN) on the same biosens or. The two sensors were then used for the determination of glutamate and L-glutamine contained in pharmaceutical formulations and the resul ts were compared with those obtained by other analytical methods.