烟酸的电化学行为与测定

用循环伏安法研究了不同支持电解质溶液中烟酸的电化学行为。烟酸在玻碳电极表面有良好的电化学响应信号。在碱性介质中，烟酸被不可逆氧化，氧化产物具有电活性，可发生准可逆氧化还原反应；在酸性介质中，烟酸发生两步准可逆氧化还原反应。结合红外、紫外光谱分析，提出了烟酸在不同酸度的介质中的电化学反应历程。并根据－０．１３Ｖ处的氧化峰电流与烟酸浓度的关系，提出了电化学测定烟酸的新方法

On the Electrochemical Behavior of Nicotinic Acid and Its Analysis

The electrochemical behavior of nicotinic acid in the presence of various electrolytes was studied by cyclic voltammetric method. Nicotinic acid gives good electrochemical response signals on the surface of glass-carbon electrodes. In alkaline phosphate buffer solutions, nicotinic acid is oxidized irreversibly. The oxidation product is electrochemically active, and undergoes a quasi _ reversible redox reaction. In acidic media, however, nicotinic acid undergoes a two _ step quasi _ reversible redox reaction. With the integrated results of IR and UV spectrophotometric analyses, an electrochemical reaction mechanism of nicotinic acid in various buffers is postulated. A new cyclic voltammetric method for nicotinic acid determination is proposed by measuring its oxidation peak current at -0.13 V.