金属钴树状高分子自组装电极制备及对鸟嘌呤电催化氧化

Electrocatalytic Activity of Cobalt(Ⅱ) Polyamidomine Dendrimer Self-assembled Electrode for Guanine

利用乙二醛、氯化钴和第5代聚酰胺．胺型树状高分子反应得到了金属钴树状高分子。通过共价自组装的方法制备了巯基丙酸单分子层修饰金电极，利用修饰电极表面的羧酸基与金属钴树状高分子末端氨基共价作用实现金属钴树状高分子固定化，制备成巯基丙酸．金属钴树状高分子修饰电极。用于鸟嘌呤的催化氧化，研究了溶液pH值、扫速、鸟嘌呤浓度的影响。结果表明，组装电极对鸟嘌呤具有很好的电催化氧化性能，并且降低了鸟嘌呤氧化电位。在pH=5．8的醋酸盐缓冲液中检测鸟嘌呤，其氧化峰电流在1．32×10^-6～46．3×10^-6mol／L浓度范围内呈良好的线性关系，其线性回归方程为，n（uA）=0．2943c＋0．8029，R^2=0．9959，检测限为6．6×10^-7mol／L。修饰电极可以很好地用于鸟嘌呤的分析检测。

Cobalt （ Ⅱ ） polyamidomine dendrimer was synthesized by glyoxal with cobalt chloride and polyamidomine dendrimer 5.0G. A gold electrode was modified with self-assembly of 3-mercaptopropionic acid, which was then reacted with cobalt（ Ⅱ ） polyamidomine dendrimer modified by the covalent interactions between the carboxyl groups on the modified electrode surface and amino terminals of the dendrimer to yield an electrode modified by the dendrimer. The sensor was used to study the electrocatalytic oxidation of guanine. The effects of pH value, scanning rate and guanine concentration were discussed. The assembled electrode had an obvious electrocatalytic activity on guanine and decreased the oxidation potential of the guanine. In an acetate buffer solution （ pH = 5.8 ）, the oxidation peak current of guanine and its concentration had a linear relationship in a range of 1.32 × 10^-6 mol/L to 46.3 × 10 ^-6 mol/L at the modified electrode. The ：regression equation was Ip（uA） =0. 294 3c ＋0. 802 9, R^2 =0. 995 9, and the detection limit was 0. 66 × 10^-6 mol/L. The modified electrode is suitable for the detection of guanine.