Automatic methods for determining nitrate and nitrite in water and soil extracts

Abstract

Automatic methods for determining nitrate and nitrite in fresh and sea water and in soil extracts with the AutoAnalyzer are described, together with details of the analytical systems. The methods are based on a modification of the manual procedure by Wood, Armstrong and Richards, which consists in reduction of nitrate with copperised cadmium and, with the nitrite thus produced, diazotisation of sulphanilamide, the product being coupled with N-1-naphthylethylenediamine to form a highly coloured azo dye, which is measured at 520 nm. The methods are capable of analysing twenty samples per hour.