聚赖氨酸/多壁碳纳米管修饰电极测定大米中的铅

Determination of Lead Ion in Rice Using Glassy Carbon Electrode Modified with Poly-L-lysine/Multi-walled Carbon Nanotubes

通过滴涂及电聚合方式分别将多壁碳纳米管和赖氨酸共修饰于玻碳电极上,制备出聚赖氨酸/多壁碳纳米管修饰电极,并建立了阳极溶出伏安法测定铅离子的新方法。采用线性扫描伏安法及循环伏安法研究了铅离子在修饰电极上的电化学行为,并考察了测定底液、底液p H值、富集电位、富集时间等条件的影响。在最佳实验条件下,铅离子的溶出峰电流与其浓度在2.0×10^-7-8.0×10^-5mol·L^-1范围内呈良好的线性关系,检出限为1.0×10^-7mol·L^-1。利用所制备的修饰电极对大米样品进行加标回收实验,回收率为98%-102%。该方法具有良好的灵敏度和稳定性,已成功应用于大米样品中铅离子的测定。

An electrochemical sensor based on multi-walled carbon nanotubes and poly-L-lysine film modified glassy carbon electrode, on which multi-walled carbon nanotubes were drop-coated and poly- L-lysine film was prepared method was established for by electropolymerization, was fabricated. And a novel electrochemical the determination of lead ion by using anodic stripping voltammetry. Electrochemical behaviors of lead ions on muhi-walled carbon nanotubes/poly-L-lysine modified carbon electrode were studied with linear scan voltammetry and cyclic voltammetry techniques. mination of lead ions was conducted under the optimal glassy Deter- experimental conditions such as choices of supporting electrolyte, pH value of the solution, amount of poly-L-lysine, deposition time and deposition potential. Results indicated that a good linear relationship between anodic stripping peak current and concentration of lead ions was observed in the range of 2. 0 × 10^ -7 - 8.0 × 10^ -5 mol × L^ -1 with a detection limit of 1.0 × 10 ^-7 mol · L^-1. A recovery experiment on rice sample was conducted by using as-prepared modified electrode, and recoveries were in the range of 98% - 102%. With good sensitivity and stability, the method was successfully applied in the determination of lead ions in rice sample.