Determination of nitrite ion by differential-pulse polarography using N-(1-naphthyl)ethylenediamine

Abstract

A highly sensitive differential-pulse polarographic method has been developed for the determination of sub-micromolar concentrations of nitrite ion after diazotisation with sulphanilic acid at low pH and coupling with N-(1-naphthyl)ethylenediamine dihydrochloride. At pH 2.0 and with 0.01 M potassium dihydrogen phosphate as the base electrolyte, the peak current at +0.020 V versus a saturated calomel electrode increases linearly in the concentration range 5 × 10^–8–2.12 × 10^–6M in simple aqueous solutions. The relative standard deviation is 3.3% for the determination of 1 × 10^–7M nitrite.