摘要
用琼脂糖(Agarose)将过氧化氢酶(Cat)固定在热裂解石墨电极表面,制备了Cat agarose膜修饰电极。包埋在琼脂糖中的过氧化氢酶可以与电极直接传递电子,在pH6.0的磷酸缓冲溶液中可得一对可逆的过氧化氢酶辅基血红素Fe(Ⅲ)/Fe(Ⅱ)氧化还原峰,式电势为-0.343V(vs.SCE)。其式电势随溶液的pH值增加而负移且呈线性关系,直线斜率为-36.8mV/pH,说明过氧化氢酶的电子传递过程伴随有质子的转移。紫外可见光谱、红外光谱表明,在琼脂糖膜中过氧化氢酶的构象保持不变。并研究了过氧化氢酶修饰电极对氧气、过氧化氢、一氧化氮的电催化性质。在16.5～278μmol/L的范围内,催化电流与过氧化氢浓度呈线性关系;在2.75～20.76mmol/L的范围内,催化电流与亚硝酸根浓度呈线性关系。
Cat-agarose film modified edge-plane pyrolytic graphite electrode(EPG) was made by entrapping catalase (Cat) in agarose hydrogel at the EPG surface.Cat confined in agarose film could directly transfer electron to EPG.A pair of redox peaks was observed in pH 6.0 buffer.The formal potential was -0.343 V,corresponding to CatFe(Ⅲ)/Fe(Ⅱ) redox couple.The formal potential of (Fe(Ⅲ)/Fe(Ⅱ)) couples in agarose membreane shifted linearly with a decrease of pH.The value of slope of was -36.8 mV/pH,which suggests that one proton transfers in the one-electron reaction.UV-vis and IR spectra indicated the similar heme environment of Cat and Cat in agarose,suggesting that Cat in agarose keeps its native conformation.The Cat-agarose modified EPG exhibited the electrocatalytic activity to oxygen,hydrogen perxide and nitric oxide.The cathodic peak current increased linearly with the concentration of H_2O_2 in the range of 16.5～278 μmol/L.The Cat modified electrode could also catalyze NO^-_2.The cathodic peak was linear with the concentration of NO^-_2 in the range of 2.75～20.76 mmol/L.
出处
《分析科学学报》
CAS
CSCD
北大核心
2004年第6期569-572,共4页
Journal of Analytical Science
基金
国家自然科学基金(No.20305011)
关键词
过氧化氢酶
电催化
直接电化学
双氧化
亚硝酸根
Catalase
Electrocatalysis
Direct electrochemistry
Hyerogen peroxide
Nitric oxide
