Determination of Nitrite in Food by Improved Colorimetry

In recent years,food safety problems related to nitrite have occurred from time to time,and traditional colorimetry has its limitations. Therefore,traditional colorimetric method was improved in this paper.The p-aminothiophenol and naphthylethylenediamine salt were respectively modified onto the gold nanoparticles,and the gold nanoparticles were aggregated by chemical reaction with NO₂^-,and the degree of aggregation was positively correlated with the concentration of NO₂^-. The standard curve of this method was R²=0.9946,the recovery rate was 97.00%~100.28%,the relative standard deviation(RSD)was 0.77%~3.88%,and the detection limit reached 5.12 ng/mL. The changes in nitrite content of three common foods were compared. Compared with the traditional colorimetric method,this method had the advantages of simple operation(one-step method),good stability,fast response and low detection limit. It could be used to analyze the production process of trace nitrite in food and water,which was conducive to the development of the food industry.