Spectrophotometric determination of nitrite in foodstuffs by flow injection analysis

A simple method for the determination of nitrite in foodstuffs by flow injection analysis is described. Nitrite samples are prepared in a microwave oven, treated with a 1 mol/lNH₄Cl solution at a pH of 9 (all under nitrogen atmosphere) and are immediately analysed. Nitrite is diazotised in the FIA system with N-(1-naphthyl) ethylenediammonium dichloride to form the highly coloured azo dye, which is measured at 540 nm. The detection limit is 0.036 mg/kg for sample injections of 400 l. The sampling rate is about 50 samples per hour and the relative standard deviation is 0.67%.