Determination and Speciation of Selenium in Pharmaceutical Samples, Spiked Veterinary Drug Samples with a Kinetic Catalytic Method

Abstract

In the present study a new kinetic catalytic method was developed for the sensitive determination of selenium in pharmaceutical formulations. The reaction between basic blue 3 (BB3) and sulphide catalysed by Se (IV) in the presence of acetic-phosphoric-boric acid buffer system. The decrease in the absorbance at 654 nm indicated the reduction of BB3. The presence of selenium (IV) accelerated the reaction rate. The method based on the linear correlation between amount of Se(IV) and reaction rate. Under optimum conditions, the linear calibration range was found as 0.1-2.0 µg ml-1 by the fixed time method for the 0.5-5 min. The tolerance limits of various species was also studied. The interfering effect of some cations such as Cr3+, Fe3+, and Hg2+ was reduced with using cation exchange resin. The proposed method was successfully applied to spiked nasal spray and veterinary drug samples. Besides, total selenium, Se (IV) and Se (VI) speciation also conducted with reducing Se (VI) to Se (IV) with HCl in the synthetic mixtures.