Studies on the Preparation of Sample Solution for Colorimetric Determination of Nitrite in Foods.

Abstract

The preparation of a sample solution for the colorimetric determination of nitrite in processed foods has been studied in detail focusing on the deproteinizing procedure. A simple and rapid deproteinizing procedure was obtained by precipitation of colloid zinc hydroxide which was formed by adding constant amounts of zinc acetate and sodium hydroxide to the alkaline extracts from salted salmon roe. The amounts of nitrite isolated from the samples of salted roe of salmon, pollack, sausage and ham fortified at 5, 50 or 70 μg/g of nitrite were determined using this procedure and the recoveries of nitrite were found to be not less than 84.8%. This preparation of sample solution is applied for the determination of residual nitrite in various foods by diazotaiztion-coupling colorimetry.