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制作了用桑色素作修饰剂的化学修饰碳糊电极 ,利用该电极为工作电极 ,建立了测定痕量铜的新方法。在甲酸钠 -盐酸缓冲溶液 (pH4.6)中 ,在0.20V(vsSCE)下搅拌富集,铜 (Ⅱ )与碳糊修饰电极表面的桑色素形成电活性络合物而吸附富集于电极表面 ,经 -0.45V静置还原后,阳极化线性扫描 ,在 -0.05V获得一灵敏的二次导数溶出峰。在不同富集时间下 ,其二次导数峰电流与铜 (Ⅱ )浓度分别在1.0×10-9～6.0×10-8 mol/L和2.0×10-8～9.0×10-7 mol/L两个范围内呈良好的线性关系 ,检出限可达4.0×10-10 mol/L(S/N=3)。同时 ,探讨了电极反应机理。方法应用于人发中的痕量铜的测定 ,获得了令人满意的结果。
A modified carbon paste electrode with morin as modifier was fabricated. A novel method for the determination of trace copper was established by using the electrode as a working electrode. The Cu (Ⅱ) complexed with Morin at the surface of the carbon paste modified electrode was adsorbed and enriched on the surface of the electrode by adsorption at 0.20 V (vsSCE) in sodium formate-hydrochloric acid buffer solution (pH 4.6) After static reduction at -0.45 V, an aniline linear scan was performed to obtain a sensitive second derivative dissolution peak at -0.05V. Under different enrichment time, the second derivative peak current and copper (Ⅱ) concentration were 1.0 × 10-9 ~ 6.0 × 10-8 mol / L and 2.0 × 10-8 ~ 9.0 × 10-7 mol / L The two ranges showed a good linear relationship with the detection limit of 4.0 × 10-10 mol / L (S / N = 3). At the same time, the electrode reaction mechanism was discussed. The method was applied to the determination of trace copper in human hair and obtained satisfactory results.