A simple method for the determination of nitrate in acidic solutions with high iron content based on the traditional cadmium reduction technique

Abstract

A simple and unexpensive method based on traditional cadmium column technique is proposed for determination of nitrate in acidic aqueous mixtures with high iron load. Solutions are alkalinized and centrifuged, subsequently the supernatant is withdrawn for nitrate analysis. By this procedure two effects are accomplished, on the one hand, pH is adjusted to a suitable value and, on the other hand, iron interference is removed by precipitation. The obtained mixture is passed through a copperized cadmium column to reduce nitrate to nitrite which is quantified spectrophometrically. This method is suitable to measure nitrate concentrations even lower than the maximum accepted limit, in artificial solution.