FIRST AND 2ND DERIVATIVE SPECTROPHOTOMETRIC DETERMINATION OF FLAVONOIDS CHRYSIN AND QUERCETIN

The first and second derivative spectrophotometric methods have been d eveloped for the determination of flavonoids chrysin and quercetin. Th e amplitudes in the first derivative spectrophotometric spectra at 256 nm and in the second derivative spectra at 268 nm were selected to de termine chrysin, while the amplitudes at 233 and 269 nm in the first a nd at 241, 258, 387 and 403 nm in the second derivative spectra were c hosen for the determination of quercetin. A linear relationship betwee n derivative amplitudes and a concentration of compounds was found. Be er's law is obeyed over a concentration range of 2-20 mu g.mL(-1) for both drug components. The method is rapid, simple, sensitive and does not require a separation step.