Aqueous Two-Phase Extraction and Spectrophotometric Determination of Nitrite in Food Samples

An ethanol-(NH (4) ) (2) SO (4) aqueous two-phase system has been applied to the extraction and spectrophotometric determination of nitrite. The complex formed by nitrite and methyl orange was extracted to the upper ethanol phase and was measured at 432 nm. The concentration of nitrite varies linearly with the absorbance over the range of similar to 0.5-6.0 mg/l. The proposed method has been applied to the determination of nitrite in food samples. The analytical results obtained by this method and the naphthyl ethylenediamine spectrophotometric method were in good agreement.