SIMULTANEOUS DETERMINATION OF AZOMICINE AND ORNIDAZOLE BY FIRST-ORDERDERIVATIVE SPECTROPHOTOMETRY

This work reports a first order derivative spectrophotometric method f or the simultaneous determination of azomicine and ornidazole in mixtu re. The foundation of this method is that the absorption of azomicine and ornidazole, in a medium containing Britton-Robinson buffer of pH=4 , depend only of the undissociated form of azomicine and of the dissoc iated form of ornidazole, and that when the first derivative of the sp ectrum was used, azomicine and ornidazole present zero crossing value at 318.4 nm and 324.4 nm, respectively. When both compounds are presen t together in a sample, it is possible to quantify one analyte in pres ence of the other. The best signal/noise ratio was found when the firs t derivative of the spectrum was used. Chemical and spectral variables were optimized for the determination of both species. It was observed a good level of repeatability (RSD < 2%). The method was applied to t he simultaneous determination of both analytes in eggs and poultry foo d.