差分脉冲伏安法对果蔬中亚硝酸盐和抗坏血酸的同时测定

Simultaneous Determination of Nitrite and Ascorbic Acid in Fruits and Vegetables by Differential Pulse Voltammetry

采用对苯二酚(Hydroquinone,HQ)催化甲烷氧化菌素(Methanobactin,Mb)还原氯金酸合成纳米金(Gold Nanoparticles,AuNPs),利用电沉积法将Mb@AuNPs修饰到裸金电极表面,制备Mb@AuNPs/Au电极。采用差分脉冲伏安法对亚硝酸盐和抗坏血酸进行同时测定并对条件进行优化,结果表明:电极组装条件为电沉积扫速100 mV/s、扫描圈数为40圈;检测体系为浓度0.20 mol/L pH6.5的磷酸盐缓冲溶液,在2~5600μmol/L和1~6000μmol/L的线性范围内,Mb@AuNPs/Au对亚硝酸盐和抗坏血酸同时检测的氧化峰电流与浓度呈良好的线性关系(R^(2)>0.9928),检出限分别为0.31和0.57μmol/L。实际样品中亚硝酸盐和抗坏血酸的加标回收率范围分别为92.59%~109.26%、90.01%~103.51%,表明该方法具有良好的重现性和稳定性,可用于果蔬中亚硝酸盐和抗坏血酸的同时测定。

Hydroquinone(HQ)was used to catalyze Methanobactin(Mb)to reduce chlorauric acid to prepare Gold Nanoparticles(AuNPs).Mb@AuNPs was modified onto the surface of a bare gold electrode via electrodeposition to prepare the Mb@AuNPs/Au electrode.Subsequently,differential pulse voltammetry was conducted for the simultaneous determination of nitrite and ascorbic acid concentrations as well as condition optimization.For the electrode assembly,electrodeposition was performed with a 0.20 mol/L and pH6.5 PBS at a 100 mV/s scan rate for 40 cycles.In the linear range of 2~5600μmol/L and 1~6000μmol/L,the oxidation peak current of both nitrite and ascorbic acid detected by Mb@AuNPs/Au showed a good linear relationship with the concentration(R^(2)>0.9928),and the limit of detection(LOD)was 0.31 and 0.57μmol/L,respectively.The recovery rates of standard addition for the actual samples were 92.59%~109.26%,90.01%~103.51%.The method has good reproducibility and stability and can be used for simultaneous determination of nitrite and ascorbic acid in fruits and vegetables.