Ledru Sophie, Boujtita Mohammed
Groupe Méthodologie Electrochimique-UMR-CNRS 6006, FCUN-CNRS 2465, Faculté des Sciences et des Techniques 2, rue de la Houssinière, B.P. 92208 44322 Nantes Cedex 03, France.
Bioelectrochemistry. 2004 Aug;64(1):71-8. doi: 10.1016/j.bioelechem.2004.03.002.
The measurements of L-lactate using the carbon paste electrode modified with lactate oxidase (LOD), horseradish peroxidase (HRP) and ferrocene (FcH) operating at low working potential in flow injection mode showed that the intensity as well as the shape of peaks were dependent on the concentration of the reducing species present in samples (e.g. ascorbate) even at low operating potentials (-200 to 0 mV vs. Ag/AgCl). The mechanism of the electrochemical contribution of ascorbate to the L-lactate response was examined by using cyclic voltammetry, hydrodynamic voltammetry and FIA results. Comparative studies showed that HRP was catalytically active for the oxidation of ascorbate leading to a decrease in the cathodic electrochemical signal of L-lactate. The results of our investigation postulated that the direct electron transfer from the HRP-Fe(III)/HRP-Fe(II) redox couple to the electrode surface was involved in the electrocatalytic oxidation of ascorbate at the electrode surface.
使用经乳酸氧化酶（LOD）、辣根过氧化物酶（HRP）和二茂铁（FcH）修饰的碳糊电极，在流动注射模式下于低工作电位测量L-乳酸，结果表明，即使在低工作电位（相对于Ag/AgCl为-200至0 mV）下，峰的强度和形状也取决于样品中存在的还原物质（如抗坏血酸盐）的浓度。通过循环伏安法、流体动力学伏安法和流动注射分析结果研究了抗坏血酸盐对L-乳酸响应的电化学贡献机制。对比研究表明，HRP对抗坏血酸盐的氧化具有催化活性，导致L-乳酸的阴极电化学信号降低。我们的研究结果推测，HRP-Fe(III)/HRP-Fe(II)氧化还原对向电极表面的直接电子转移参与了电极表面抗坏血酸盐的电催化氧化。
