Analysis of mixtures of oxytetracycline and riboflavine by first-derivative synchronous spectrofluorimetry

Abstract

The simultaneous determination of oxytetracycline and riboflavine in mixtures by first-derivative synchronous spectrofluorimetry is described. The proposed method is based on the formation of a fluorescent complex between aluminium and oxytetracycline, and on the native fluorescence of riboflavine. The constant wavelength difference between the excitation and emission wavelengths in a synchronous scan has been optimized by analysing the multi-dimensional information obtained on the excitation–emission matrices. The combination of synchronous scanning spectrofluorimetry and differentiation of the spectra allows for the complete resolution of the mixture. The method has been applied to the determination of these drugs in pharmaceutical preparations.