石墨烯修饰电极的制备及对食品中亚硝酸盐的检测

Preparation of Graphene Modified Electrode and Its Application in the Determination of Nitrite in Food

采用循环伏安法成功自制石墨烯修饰玻碳电极,考察了其电化学沉积的最佳缓冲液和pH值条件,并应用于检测食品中的亚硝酸盐。结果表明,该石墨烯修饰电极最佳检测环境为pH7.0的0.10 mol/L PBS缓冲液,亚硝酸根检测的线性关系范围为1×10^(–6)~1×10^(–2) mol/L,检出限为7.2×10^(–8) mol/L,相关系数r为0.9956。抽检市售生抽酱油、辣白菜、乳粉等7种食品,除熟制菠菜亚硝酸盐含量超标外(47.26 mg/kg),其余食品均符合国家食品亚硝酸盐含量标准,相对标准偏差(RSD)为2.38%~5.92%,加标回收率为96.7%~103.0%。建立起高效且检出限低的快速检测、定量分析食品中亚硝酸盐含量的方法,有助于保障食品安全和人民群众的生命健康。

In this study,the graphene modified electrode was successfully prepared by cyclic voltammetry.The optimal buffer solution and pH conditions of the electrode were investigated and applied to the determination of nitrite in food.The results showed that the optimal detection environment of the graphene modified glassy carbon electrode was 0.10 mol/L PBS buffer at pH 7.0.The linear range of nitrite detection was 1×10^(–6)~1×10^(–2) mol/L,the detection limit was 7.2×10^(–8) mol/L,and the correlation coefficient was 0.9956.Seven kinds of food such as soy sauce,kimchi and milk powder sold in the market were sampled.Except that the nitrite content of cooked spinach exceeded the standard (47.26 mg/kg),other food met the national food nitrite content standard.The average relative standard deviation (RSD) was 2.38%~5.92%,and the recoveries were 96.7%~103.0%.The establishment of an efficient and low detection limit method for rapid detection and quantitative analysis of nitrite content in food will help to ensure food safety and the health of people.