金/有机硅复合纳米颗粒修饰金电极的方波溶出伏安法测定痕量Hg(II)

Gold/Organosilica Composite Nanoparticles Modified Gold Electrode for Determination of Trace Hg(II) by Square Wave Stripping Voltammetry

采用3-巯丙基三甲氧基硅烷（MPTS）为单一硅源,以金纳米粒子（AuNPs）为MPTS水解凝胶颗粒的固着载体,制备了AuNPs/MPTS凝胶复合纳米粒子修饰电极.采用原子力显微镜及透射电镜观察纳米粒子的形貌及大小,并采用循环伏安法比较不同金纳米粒子含量对修饰电极电化学行为的影响.方波溶出伏安法试验表明,该修饰电极对Hg（Ⅱ）的检测具有灵敏的响应,多种离子不产生干扰.在优化后的测试条件下,即在0.1 mol/L的HC1溶液中,0.2V电位下富集15 min,Hg（Ⅱ）浓度分别为1×10^-9～1×10^- 8 mol/L和5×10^-8～5×10^-7 mol/L时,溶出峰电流与Hg（Ⅱ）浓度呈线性关系,相关系数分别为0.998 0和0.998 5.当富集时间为15 min时,Hg（Ⅱ）浓度检测限可达1×10^-10 mol/L（信噪比为3）,且所制备的复合纳米膜具有良好的导电性和电极重现性,可用以制作Hg（Ⅱ）电化学传感器.

Gold nanoparticles （AuNPs）/3-mercaptopropyl trimethoxysilane （MPTS） nanocomposite modified gold electrode was prepared with MPTS as a single silica source, and AuNPs as the gel carrier. Atomic force microscopy and transmission electron microscopy were applied to get the morphology and size of the nanoparticles. With the different amount of AuNPs added, the electrochemical behavior of the obtained AuNPs/MPTS modified electrodes were characterized by cyclic voltammetry. Square wave stripping voltammetry has been used for the determination of Hg（Ⅱ） without interference from multiple ions. The modified electrode had a sensitive response to Hg（II） under the optimized conditions. The stripping peak currents of Hg（Ⅱ） and the concentrations presented good linear relationships with both ranges of ×10^-9～1×10^- 8 mol/L（R2 = 0. 998 0） and 5 ×10^-8～5×10^-7 mol/L（R2 = 0. 998 5）. The detection limit was down to 1 ×10^-10 mol/L （signal to noise ratio is 3） when increasing thepreconcentration time to 15 min. The AuNPs/MPTS nanocomposite electrode had a good electrical conductivity and the reproducibility, promising for Hg（Ⅱ） electrochemical sensor.