基于血红蛋白-蒙脱土膜的修饰电极在三氯醋酸检测中的应用(英文)

Direct Electron Transfer for Hemoglobin in Sodium Montmorillonite Films on Pyrolytic Graphite Electrodes and Its Application to the Electrochemical Detection of Trichloroacetic Acid

三氯醋酸产生于工业废弃物及水的氯化过程 ,是重要的环境污染物 .对于它的检测 ,常用的方法比较繁琐 .应用血红蛋白 -蒙脱土膜修饰热解石墨电极 ,将血红蛋白包埋于修饰在热解石墨电极上的蒙脱土内 ,进行循环伏安实验 ,可以得到血红蛋白的直接电化学响应 ,在pH 4.0 0 .1mol/L柠檬酸缓冲液中 ,于- 0 .2 92V处出现一对准可逆的氧化还原峰 (相对于饱和甘汞电极 ,VS.SCE) .经紫外 -可见光谱和傅利叶红外光谱测定 ,包埋在蒙脱土膜内的血红蛋白仍保持与其天然状态相似的二级结构 ,而且将三氯醋酸加入上述体系中 ,发现该修饰电极对三氯醋酸具有催化功能 .表观米氏常数的测定结果显示 ,该参数可作为这种电极与底物三氯醋酸作用的酶性质的表征 .同时血红蛋白 -蒙脱土膜修饰热解石墨电极性质稳定 ,对于三氯醋酸 ,显示出了酶样的催化作用特性 ,特异性高 .因此水中虽然存在一些浓度高于三氯醋酸三倍的相关干扰物质的同时 ,该电极仍显示出了良好的选择性 ,并具有方便、快捷的特点 .还从电化学的角度出发 ,探讨了血红蛋白

Stable thin films made from sodium montmorillonite with incorporated hemoglobin(Hb)on pyrolytic graphite(PG)electrodes were characterized by electrochemical analysis.Cyclic voltammetry(CV)of Hb_montmorillonite films showed a pair of well defined and nearly reversible peaks at about-0.292V vs.saturated calomel electrode(SCE)at pH4.0,showing greatly facilitated direct electron transfer between Hb and PG electrodes in montmorillonite films.UV_Vis absorption spectroscopy and FT_IR spectroscopy suggested that Hb keeps its secondary structure similar to its native state when incorporated in the film.Moreover,this modified electrode exhibited the catalysis activity to trichloroacetic acid(TCA),and the TCA reductive peak current is in proportion to its concentration.The apparent Michaelis_Menten constant was about2.37mmol/L.The methods is prospective based on Hb_montmorillonite modified electrodes for detection of TCA.The possible interference in real sample analyses is discussed.