Determination of gatifloxacin in drug formulations, human urine, and serum samples using energy transfer chemiluminescence coupled with flow-injection analysis

A simple and sensitive method for the determination of gatifloxacin (GFLX) is developed by using flow injection analysis with potassium permanganate-sodium sulfite chemiluminescence (CL) detection based on the energy transfer from GFLX to terbium(III). Intense signal instead of the weak CL produced by potassium permanganate-sulfite-GFLX system can be observed when Tb(III) is added to the system. A narrow and intense emission band at 545 nm arising from the excited-state Tb(III) was obtained. Under the optimum conditions, a linear range was 5.0 x 10(-8) to 8.0 x 10(-6) M and the detection limit was 3.2 x 10(-9) M. The method has been successfully applied to the determination of gatifloxacin in drug formulations, urine and serum samples. There was no interference from some common excipients used in pharmaceutical preparations. The possible energy transfer mechanisms in the lanthanide complexes were discussed.