多巴胺在硫堇衍生化自组装膜修饰金电极上的伏安行为及其安培测定

Electrochemical Behaviours and Amperometric Determination of Dopamine at Gold Electrode Modified by Thionine Covalenyly Bound to Self -assembled Monolayers

研究了多巴胺（ＤＡ）在硫堇衍生化自组装膜修饰金电极（Ｔｈ－ＳＡＭ／ＡＵｕ）上的电化学行为。ＤＡ在该修饰电极上的△Ｅｐ～７０ ｍＶ，循环伏安峰形对称，氧还峰电流之比接近 １，为准可逆反应。研究了温度、ｐＨ对ＤＡ氧化还原的影响，并求得了其热力学参数。在选定的条件下，峰电流与ＤＡ的浓度在１．０ × １０－６～１．０×１０－３ｍｏｌ／Ｌ的范围内呈线性关系，相关系数为０．９９２３，可用于ＤＡ的灵敏测定。

The electrochemical behaviours of dopamine at the thionine derivatized-self-as- sembled monolayer modified gold electrode have been studied. The experimental results show that the difference between Epa and Epc is 70 mV, the shape of peaks is symmetric and the ratio of anodic and cathodic peaks is about l, which suggests that the electrode process is quasi-reversible one. According to the temperature coefficient of Eo', a series of thermody- namic parameters such as △so, △Ho and △Go were calculated. Under the optimal conditions, the relationship of ipa-CDA is linear in the range of 1. 0× 10-6~1. 0× 10-3 mol/L with the cor- relation coefficient of 0. 9923.