The use of iron (II) sulphate for the reduction of nitrate to ammonia in the microdiffusion method for determining nitrate in soil extracts

Abstract

Because of the variable nature of technical titanium(III) sulphate normally used for the determination of nitrate in soil extracts by the Bremner-Shaw microdiffusion method, the possibility of replacing this reagent with iron(II) sulphate was studied. It was found that 1 ml of M iron(II) sulphate (in 0·5 M sulphuric acid)plus 0·1 ml of saturated silver sulphate could be used to successfully determine up to 200 µg of nitrate nitrogen in 5-ml aliquots of soil extracts.