氯过氧化物酶修饰电极对一氯二甲酮的催化氯化

Catalytic Chlorination of MCD Using Chloroperoxidase Coated by Single-Wall Carbon Nanotubes Films on GC Electrodes

通过将氯过氧化物酶溶液(Chloroperoxidase,CPO)与Nafion分散的单壁碳纳米管分散液混合后直接滴涂到玻碳电极表面制得修饰电极.这个固定了氯过氧化物酶的碳纳米管修饰玻碳电极,在pH=5.0的磷酸缓冲溶液中测得的循环伏安曲线上有一对准可逆的氧化还原电流峰,经过与裸电极和没有固定氯过氧化物酶的碳纳米管修饰电极上测得的循环伏安行为对比后确认,碳纳米管对氯过氧化物酶与电极之间的电子传递反应具有很好的促进作用.利用该修饰电极能催化一氯二甲酮氯化为二氯二甲酮,无需添加过氧化氢作为反应启动剂,紫外光谱的测试结果表明,每摩尔氯过氧化物酶可催化氯化4.0×105mol的一氯二甲酮,表现出很高的催化效率.

A simple immobilized method of chloroperoxidase（CPO） was reported, that is, 1μL CPO solution was mixed with 2μL carboxylated SWNTs [ 1 mg/mL, which was dispersed in 0. 5 % （ mass fraction） Nation ], droped onto the surface of glass carbon （ GC ） electrode. The electrochemical behavior of the CPO/SWNTs modified GC electrode was investigated by cyclic vohammetry. A pair of well-defined redox peaks was observed in pH 5 phosphate buffer solutions. In contrast to no peaks for bare GC in CPO solution and only SWNTs coated electrode in phosphate buffer solutions, it is suggested that SWNTs promote the direct electron transfer between the CPO and the GC electrode. The redox peak current has no change in the scan rate range from 5 to 1000 mV/s. The formal potential is -300 mV. The peak separation is about 90 mV at the scan rate of 100 mV/s. Furthermore, the CPO/SWNTs modified GC electrode was used to catalyze chlorination of monochlorodimedone（MCD）. A total turnover number of 4.0×10^5 was obtained, indication of good catalysis efficiency.