Nafion／MB／HRP酶电极的制备及在测定植物油过氧化值中的应用

Preparation of Nafion/MB/HRP Electrode and its Application in Determination of Peroxide Value of Vegetable Oils

研究了Nafion／MB／HRP酶电极在有机相介质中对油脂过氧化物还原的催化能力，阐述了亚甲基蓝-HRP一过氧化月桂酰之间的氧化还原过程及机理；Nafion／MB／HRP酶电极在有机相介质的电极过程属于表面电化学控制过程而非蛋白质扩散控制过程；所制备的Nafion／MB／HRP酶电极在所选有机相表现出良好的稳定性和重现性；Nafion／MB／HRP酶电极对过氧化月桂酰的催化还原电流响应在2．5×10^-6～2．3×10^-4mol／L浓度范围内有较好的线性关系：△Ipred=0．0163×CLHP＋0．0091，（R=0．998）；Nafion／MB／HRP酶电极法应用于实际油样的检测，结果与标准的碘量法一致，但精度和准确度高于标准碘量法。

The catalytic effect of Nafion/MB/HRP modified electrode on the electrochemical reduction of lipid hydroperoxide in organic phase was investigated. The mechanism of redox process of MB - HRP- lauroyl peroxide was expounded. The electrode process of Nafion/MB/HRP modified electrode is typically controlled by electrochemical reaction on the electrode surface, instead of diffusion of HRP protein. Excellent stability and reproducibility of the prepared Nation/ MB/HRP modified electrode was observed in the selected organic media. The operational parameters such as modified film thickness, HRP enzyme concentration, organic solvents composition, holding potential, have been explored for the optimum analytical performance of the enzyme electrode. The catalytic reduction current of lauroyl peroxide at Nafion/MB/HRP modified electrode increases linearly with the concentration of substrate in the range of 2.5 x×10^-6- 2.3 × 10^-4 mol/L（R = 0. 998）. Nafion/MB/HRP modified electrode was applied to the determination of peroxide value of vegetable oil samples, and the results well agreed with the classical iodometry method.