壳聚糖-多壁碳纳米管修饰玻碳电极差分脉冲溶出伏安法测定痕量钯

将多壁碳纳米管(MWCNT)分散于壳聚糖（CTS）溶液中，修饰在玻碳电极（GCE）表面，制成了壳聚糖-多壁碳纳米管修饰玻碳电极(CTS-MWCNT-GCE)。利用差分脉冲溶出伏安法研究了钯在该电极上的溶出伏安特性，优化了试验条件,提出了一种测定痕量钯的新方法。试验发现，在0.1 mol/L乙酸钠-0.1 mol/L盐酸缓冲溶液（pH 4.10）中，钯于－400 mV处被富集在该修饰电极表面，在-300 mV～400 mV电位范围内，以100 mV/s的速率扫描，钯在135 mV（vs. SCE）处出现一灵敏的溶出峰，峰电流与钯的浓度在1.88×10-9～1.69×10-8 mol/L范围内呈良好的线性关系，检出限为3.10×10-10 mol/L。该修饰电极具有良好的稳定性和重复性，在含有1.0×10-9 mol/L钯的溶液中，连续11次测定，其相对标准偏差(RSD)为0.21 %。方法用于矿样中痕量钯的测定，测定结果同火焰原子吸收光谱法（FAAS）的测定结果基本一致。

Determination of trace palladium by differential pulse stripping voltammetry using a chitosan-multi-wall carbon nanotubes modified glassy carbon electrode

Multi-wall carbon nanotubes (MWCNT) were dispersed in chitosan (CTS) solution, and the mixture obtained was used in modifying the surface of glassy carbon electrode (GCE) to prepare chitosan-multi-wall carbon nanotubes modified glass carbon electrode (CTS-MWCNT-GC). The stripping voltammetric characteristics of palladium at this electrode were studied with differential pulse stripping voltammetry. A new method for the determination of trace palladium was described after the determination conditions were optimized. It was found that palladium could be enriched on the surface of this modified electrode at -400 mV in 0.1 mol/L sodium acetate -0.1 mol/L hydrochloric acid buffer solution (pH 4.10). When scanning from -300 mV to 400 mV at the rate of 100 mV/s, , a sensitive differential pulse stripping peak appeared at 135 mV (vs. SCE) for palladium. The peak current showed good linearity with the concentration of palladium in the range of 1.88×10-9-1.69×10-8 mol/L. Detection limit was 3.10×10-10 mol/L. The modified electrode showed good stability and reproducibility. The relative standard deviation (RSD) was 0.21 % for 11 continuous determinations of 1.0×10-9 mol/L Pd solution. This method has been applied to the determination of trace palladium in ore samples, and the results were consistent with those obtained by FAAS.