辣根过氧化物酶在碳纳米管-离子液体修饰碳糊电极上的直接电化学研究

Direct Electrochemistry of Horseradish Peroxidase Immobilized on Carbon Paste Electrode Modified by MWCNTs and Liquid [EMIM]PF_6

以室温离子液体1-丁基-3-甲基咪唑六氟磷酸盐（[EMIM] PF6）为粘合剂与多壁碳纳米管（Multi-walled carbon nanotubes,MWCNTs）、石墨粉相混合制备新型碳糊电极,并在该电极表面修饰辣根过氧化物酶（HRP）制成新型碳糊酶电极（HRP-MWCNTs-CILE）.应用循环伏安法（CV）和计时电流法（it）研究了该修饰电极的直接电化学行为.结果表明,该修饰电极在pH 6.0的0.05 mol/L磷酸缓冲溶液中,其循环伏安曲线上出现了1对准可逆的氧化还原峰,为HRP中Fe（Ⅲ）/Fe（Ⅱ）电对的特征峰.该修饰电极对过氧化氢具有良好的催化活性、抗干扰能力和稳定性.在最佳条件下,修饰电极对H2O2的测定线性范围为7.0×10-6～3.0×10-3 mol/L,检出限（S/N=3）为2.5×10-6mol/L.该传感器具有制备简单、成本低廉、响应快等特点,具有较好的应用前景.

New carbon paste electrodes （HRP-MWCNTs-CILE） were prepared by using multiwalled carbon nanotubes（MWCNTs） and room temperature ionic liquid 1-ethyl-3-methylimidazolium hexafluorophosphate（[EMIM] PF6） as binder.Then horseradish peroxidase（HRP） was modified on the surface of the electrode.The direct electrochemical characteristics of the modified electrodes were investigated by cyclic voltammetry（CV） and chronoamperometry（it）.A pair of approximate reversible redox peaks on CVs were observed in phosphate buffer.The enzyme electrodes showed good catalytic activity for hydrogen peroxide and good anti-interference ability and stability.Under the optimal conditions,the biosensor showed a wide linear response to H2 O2 in the range of 7.0 × 10-6-3.0 × 10-3 mol/L with a detection limit（S/N =3） of 2.5 × 10-6 mol/L.The sensor showed the characteristics of simple preparation,low cost,fast response and good application prospect.