黄素腺嘌呤二核苷酸在热石墨柱电极上电化学行为及吸附溶出分析

Electrochemical Behavior and Adsorptive Stripping Analysis of Flavin Adenine Dinucleotide at Electrically Heated Graphite Cylindrical Electrodes

研究了黄素腺嘌呤二核苷酸(FAD)在热石墨柱电极上的电化学行为。发现对吸附有FAD的电极加热同时进行循环伏安扫描,随电极温度升高,氧化还原峰电位负移,峰电流减小,峰形变差。采用方波伏安进行吸附溶出分析,如果只在吸附步骤对电极加热,室温溶出,则随电极温度升高,溶出峰电流显著增加。这主要归因于直接对电极加热引起的强制热对流,这种对流能提高传质,促进吸附,增强溶出响应。5min预富集对电极加热到72℃,检出限可以达到1×10-8mol/L(S/N=3),比室温27℃时降低了一个多数量级,相应灵敏度也明显提高。

Electrically heated graphite cylindrical electrodes （HGCEs） have been used to perform electro- chemical behavior studies and adsorptive stripping square wave vohammetric （SWV） measurements of flavin adenine dinucleotide （FAD）. It was found that when the electrode with adsorbed FAD was heated during cyclic vohammetric cycling, the redox peak potential shifted negatively, peak current diminished and the peak shape became poorer. While the SWV stripping peak current was significantly enhanced with increasing the electrode temperature only during preconcentration step. This enhancement was due to the forced thermal convection induced by heating the electrode rather than the bulk solution. It is the thermal convection that has the ability to improve mass thransfer and facilitate adsorption thus enhance stripping responses. It was found that the detection limit of 1 ×10^-8mol/L（S/N = 3）could be obtained at an electrode temperature of 72 ℃ during 5 min accumulation, about one magnitude less than that at room temperature 27℃. The sensitivity was also improved significantly.