石墨烯修饰电极电化学阻抗法测量油脂的氧化诱导时间

Determination of Oil's Oxidation Induction Time with Graphene Modified Electrode by Electrochemical Impedance Spectroscopy

分别采用滴涂法制备石墨烯(GR)-壳聚糖(CS)修饰玻碳电极(GR-CS/GCE),以及电沉积-还原氧化石墨烯(GO)修饰玻碳电极(rGO/GCE),并对修饰电极进行了电化学表征。结果表明,rGO/GCE比GR-CS/GCE及GCE有较小的电子转移阻抗和较大的表观活性面积。rGO/GCE电极的制备条件为GO悬浮液浓度1.0g/L、扫描速度20mV/s和电沉积30圈。优化了油脂阻抗测量条件,研究了油脂样品在rGO/GCE上的交流阻抗行为。根据rGO/GCE可以快速、准确地测量实际油脂样品(杏仁油)氧化过程中阻抗值及其变化,据此建立了一种简便、灵敏和准确测量油脂氧化诱导时间的电化学分析方法。

Graphene modified electrodes were constructed with drip-coating and electro-deposition.The conditions for the electrodes modification and the electrochemical characteristics of the modified electrodes were investigated.The experimental results revealed that the reduction graphene oxide（rGO）modified electrode（rGO/GCE）had smaller electron transfer impedance and larger active surface area than those of graphene（GR）/chitosan（CS）modified electrode（GR-CS/GCE）and GCE.The optimum modification conditions of rGO/GCE electrode were 1.0g/L of GO,20mV/s of the scanning rate and 30 cycles of electro-deposition.The parameters for the determination of oil impedance were studied.It was found that rGO/GCE can be used to determine the oil impedance and the impedance variation in the process of oil oxidation sensitively and rapidly.Therefore,a simple,sensitive and accurate method for the determination of oil＇s oxidation induction time was established.