基于混合气凝胶负载银纳米粒子构建电化学传感器用于食品过氧化氢的测定

Construction of an Electrochemical Sensor Based on Mixed Aerogels Loaded with Silver Nanoparticles for the Determination of Hydrogen Peroxide in Foods

以聚多巴胺为“胶联剂”将羧基碳纳米管和被透析的氧化石墨烯通过氨基、羧基等基团键合形成3维分层多孔结构的混合气凝胶,并以混合气凝胶为基底原位负载银纳米粒子,建立一种有效检测食品中过氧化氢的电化学方法。最佳条件为pH 7.4、工作偏压-0.4 V、电极修饰液体积5μL,以AgNPs-MAs修饰电极为工作电极对过氧化氢的响应电流是裸玻碳电极的24.5倍。采用计时电流法快速、灵敏检测过氧化氢,其峰电流与浓度呈良好线性关系,其线性方程为I=0.32c+1.66(相关系数0.9993),检出限0.02μmol/L(信噪比3)。此外,该传感器具有较高的准确性、稳定性和抗干扰性,能实现重复利用。该传感器应用于牛奶中过氧化氢的测定,回收率为98.1%~98.8%,相对标准偏差为0.58%~2.28%,有望应用于食品中过氧化氢的快速、痕量检测。

Carboxy carbon nanotubes and dialyzed graphene oxide were bound via amio and carboxyl groups using polydopamine as a cross-linking agent to form a three-dimensional mixed aerogel(MA)with a hierarchical porous structure.Silver nanoparticles were loaded in situ onto MA to develop an efficient electrochemical method for the detection of hydrogen peroxide in foods.The response current to hydrogen peroxide of AgNPs-MA modified electrode was 24.5 times higher than that of bare glassy carbon electrode under the optimal conditions(pH 7.4,working bias of−0.4 V and 5μL of modified electrode solution).Chronoamperometry was used to detect hydrogen peroxide rapidly and sensitively.The peak current of the modified electrode had a good linear relationship with the concentration of hydrogen peroxide,which was fitted the following equation:I=0.32c+1.66(R^(2)=0.9993),and the limit of detection(LOD)was 0.02μmol/L(signal-to-noise ratio,R_(SN)=3).In addition,the electrochemical sensor had high accuracy,stability and anti-interference performance,and could be reused.The sensor was applied to the monitoring of hydrogen peroxide in milk,with a recovery rate of 98.1%–98.8%and a relative standard deviation(RSD)of 0.58%–2.28%.It is expected to be applied to the rapid trace detection of hydrogen peroxide in foods.