Spectrophotometric determination of ajmaline and brucine by Folin Ciocalteu's reagent

A rapid and simple spectrophotometric procedure is described for the determination of ajmaline and brucine. The method is based on the development of blue coloured product due to reduction of tungstate and/or molybdate in Folin Ciocalteu's reagent (FCR) by ajmaline and brucine in alkaline medium. The colour is stable for more than 48 h. The chromogenic reaction has lambda(max) at 540 nm with molar absorptivity 1.64 X 10(4) and 2.37 x 10(3) 1 mol(-1) cm(-1) in the Beer's law range 1-8 mug ml(-1) and 10-100 mug ml(-1) for ajmaline and brucine. respectively.