KINETIC FLUOROMETRIC-DETERMINATION OF AMINOGLYCOSIDE ANTIBIOTICS BY USE OF OPA AND N-ACETYLCYSTEINE AS REAGENTS

The use of N-acetylcysteine for the kinetic fluorimetric determination of aminoglycoside antibiotics by reaction with o-phthaldialdehyde (OP A) in a basic medium was studied. The results obtained show that this thiol is a satisfactory substitute for 2-mercaptoethanol as reagent fo r the formation of isoindole derivatives of compounds containing prima ry amines such as amikacin, kanamicin and tobramycin, while avoiding i ts unpleasant odour. Due to the fast formation of the fluorescent deri vatives the stopped-flow mixing technique must be used in order to acq uire analytical kinetic data. This allowed the development of a kineti c automatic method for the determination of amikacin;applicable to rou tine analyses. The initial rate was measured within ca. 5 s and the ca libration graph was linear over the range 0.05-30.0 mu g mL(-1). The m ethod was satisfactorily applied to the determination of amikacin in t wo pharmaceutical preparations with a mean recovery of 98.7%.