High-performance liquid chromatographic methods for determination of gentamicin in biological fluids

A selective and sensitive methods for the determination of gentamicin in plasma and urine by high-performance liquid chromatography has been developed. Following deproteinization, the gentamicin is reacted with fluorescamine to produce a fluorescent derivative. This reaction mixture is directly chromatographed on a cation exchange column using as mobile phase acetonitrile-phosphoric acid (7:3). The gentamicin compounds elute as a single peak. Using 0.1 ml of plasma, quantitation of gentamicin concentration as low as 1 mg/l are possible. Possible interference from other aminoglycosides and antibiotics is discussed.