Determination of diclofenac sodium, famotidine and ketorolac tromethamine by flow injection analysis using dichloronitrophenol.

Diclofenac sodium, famotidine and ketorolac tromethamine were determined by flow injection analysis (FIA) with spectrophotometric detection. The sample solutions (5-50 micrograms ml-1 of diclofenac sodium, 10-80 micrograms ml-1 of famotidine and 10-120 micrograms ml-1 of ketorolac tromethamine) in methanol were injected into a flow system containing 0.01% (w/v) of 2,4,dichloro-6-nitrophenol (DCNP) in methanol. The colour produced due to the formation of a charge transfer complex was measured with a spectrophotometric detector set at 450 nm. A sampling rate of 40 per hour was achieved with high reproducibility of measurements (RSD below 1.6%). The FIA method was applied to the determination of diclofenac sodium, famotidine and ketorolac tromethamine in pharmaceutical formulations.