Spectrophotometric determination of vanadium by hydroxylamine hydrochloride

A rapid and accurate method for spectrophotometric determination of vanadium based on simple reduction of pentavalent vanadium by hydroxylamine hydrochloride in hydrochloric acid medium has been reported. The absorbance of the blue coloured solution is measured at 760nm. The system obeys Beer's Law strictly within the range of 5 to 40mg vanadium per 100ml solution. The precision and accuracy of the technique were tested by analysing solutions containing known amount of vanadium. The average of seven determination with 20 mg vanadium in 100 ml solution is 20-10 which varies between 19-85 to 20-32 at 95% confidence limit. This method was applied for the analysis of vanadium in ferro-vanadium and satisfactory results were obtained. Effects of acidity, time and reagents have been studied. The molar extinction coefficient of the method was found to be 17. Dr.L.P. Pandey, Scientist, National Metallurgical Laboratory)