Determination of Trace Amounts of Nitrite Ion by Kinetic-Spectrophotometric Method on Acidic Media Based on Reduction of Cresyl violet

Nitrite is a characteristic and the determination of its concentration at trace levels is important in biological and environmental studies. A simple sensitive and rapid method for determination of trace amount of nitrite ion in real samples is reported. The reaction is initiated by adding known volumes of a nitrite ion solution of identified concentration to acid solutions of cresyl violet, which the color of reagent changes to yellow vs time. Then, the absorbance changes is monitored spectrophotometrically at λ_max = 555 nm for the range 0.0184–2.39 μg.ml⁻¹ and at γ_max = 405 nm for the range of 2.4–6.4 μg.ml⁻¹ of nitrite ion at 25°C. Many of cations and anions have no interfering effect but I, N₃⁻, WO₄⁻ and S₂O₃²⁻ ions do interfere. This method was used to determine nitrite ion concentration in foodstuffs such as sausages.