锡(Ⅱ)在壳聚糖-多壁碳纳米管修饰玻碳电极上的电化学行为及其测定

Electrochemical behavior of stannum at chitosan and multi-wall carbon nanotubes modified glassy carbon electrode and its determination

制备了壳聚糖(CTS)-多壁碳纳米管(MWCNT)修饰玻碳(GCE)电极,利用差分脉冲溶出伏安法研究了锡(Ⅱ)在该电极上的电化学行为,探讨了电极反应机理。在优化测定条件的基础上,提出了一种测定痕量锡(Ⅱ)的新方法。在1.0mol/L的盐酸溶液中,于-1 000mV电位处锡(Ⅱ)被富集在修饰电极表面,在-1 000～0.00mV电位范围内,以800mV/s的扫描速率,锡(Ⅱ)在-630mV电位处产生一灵敏的溶出峰,峰电流与锡(Ⅱ)的浓度在4.2×10-8～1.3×10-5 mol/L范围内呈良好的线性关系,检出限(S/N=3)为3.1×10-9 mol/L。方法应用于生铁和合金钢样品中痕量锡(Ⅱ)的测定,结果与火焰原子吸收光谱法(FAAS)的测定结果基本一致。

The chitosan and multi-wall carbon nanotubes modified glass carbon electrode（CTS-MWCNT-GC） was successfully prepared.The electrochemical behavior of stannum（Ⅱ） at CTS-MWCNT-GC and the corresponding reaction mechanism of electrode were investigated by differential pulse stripping voltammetry.A new method for the determination of trace stannum（Ⅱ） was described by optimizing the determination conditions.It was found that in 1.0 mol/L HCl solution,stannum（Ⅱ） was accumulated on the surface of the modified electrode at-1 000 mV.When scanning linearly was from-1 000 mV to 0.00 mV at a scan rate of 800 mV/s,a sensitive stripping peak of stannum（Ⅱ） appeared at-630 mV.The peak current showed good linearity with the concentration of stannum（Ⅱ） in the range of 4.2×10-8-1.3×10-5 mol/L.Detection limit was 3.1×10-9 mol/L.This method has been applied to the determination of tracing stannum（Ⅱ） in pig iron and alloy steel samples,and the results were consistent with those obtained by FAAS.