Spectrophotometric determination of nitrite in curing meat samples basing on the nitrosation reaction

Abstract

A new Spectrophotometric method for the determination of nitrite ion was studied. The method is based on the nitrosation reaction of nitrite ion with tryptophan in sulphuric acid medium. During it's reaction with nitrite, an intensively yellow-coloured substance is formed, having maximum absorption at 440nm. The calibration curve showed that Beer s law obeyed over the range of 0.05-3.0μg/ml of nitrite, with a detection limit of 0.00μg/ml. The molar absorptivity and Sandell index were 1.3887*104 L/mol.cm and 0.00331μg/cm² respectively. The optimum conditions affecting and interferences of the foreign ions were studied. The results obtained of the proposed method for determination of nitrite in meat samples were agreed with those obtained by the Naphthyl ethylene diamine NEDA standard method.