金纳米粒子修饰电极循环伏安法测定食品中的碘

Determination of Iodine in Food by Gold Nanoparticles Modified Electrode Cyclic Voltammetry

为寻求一种快速、简便、灵敏的食品中碘的测定方法,利用循环伏安法(CV)构建金纳米粒子修饰电极检测碘离子(I-)体系。利用甲烷氧化菌素(Mb)原位还原纳米金(Mb@AuNPs),电沉积法制备自组装修饰电极。通过透射电子显微镜对Mb@AuNPs表征,CV考察碘离子的电化学行为。确定碘离子检测的优化条件为:电沉积扫描速率0.11 V/s、扫描圈数30圈、缓冲溶液浓度0.05 mol/L、缓冲溶液pH6.5。氧化峰电流与I-浓度在0.01~10.00μmol/L范围内有良好的线性关系,R2为0.9992,检出限为2.88 nmol/L(S/N),定量限为9.60 nmol/L,该方法检测不同食品中碘含量的加标回收率为96.22%~103.57%。结果表明该修饰电极对I-的测定具有良好的精密度、稳定性和重现性,以及较好的抗干扰能力,符合测定方法要求,可用于实际样品中碘的测定。

In order to find a rapid, simple and sensitive method for determination of iodine in food, a gold nanoparticle modified electrode was constructed by cyclic voltammetry(CV) to detect iodine ion(I-). In situ reduction of gold nanoparticles(Mb@AuNPs) using methanobactin(Mb), and the self-assembled modified electrode was preparaed by electrodeposition. Mb@AuNPs was characterized by transmission electron microscope(TEM), the electrochemical behavior of iodine ion(I-) was investigated by CV. The optimized conditions for iodine ion detection were as follows:Electrodeposition scanning rate 0.11 V/s, number of scanning cycles 30, buffer concentration 0.05 mol/L, buffer pH 6.5.There was a good linear relationship between oxidation peak current and I-concentration in the range of 0.01~10.00μmol/L, R2 was 0.9992. The detection limit was 2.88 nmol/L(S/N), and the quantitation limit was 9.60 nmol/L. The recoveries of iodine content in different foods were 96.22%~103.57%. The results show that the modified electrode has good precision, stability, reproducibility and anti-interference ability for the determination of I-, which meets the requirements of the determination method and can be used for the determination of I-in practical samples.