基于Vc的液体食物抗氧化能力测定电极研究-农产品加工与贮藏工程专业论文.docxVIP

2．验证厂循环伏安法表征聚吡咯掺杂亚铁氰化钾复合膜修饰铂电 2．验证厂循环伏安法表征聚吡咯掺杂亚铁氰化钾复合膜修饰铂电 极的电化学性质的可行性，即对抗坏血酸(Vc)的氧化具有良好的催 化作用。以5．0X 10。mol／L的Vc作为测试对象，与裸电极相比，阳极 峰电位负移近250my，阳极峰电流也增加为4—5倍。在pH5．0PBS缓冲 溶液巾，抗坏血酸在修饰电极上的响应电流与其浓度在5×10一～10一 1mol／L范围内呈良好的线性关系，相关系数R2=O．9959，检测限为 2．5×10一mol／L。 3．运用二元线性拟合的数据处理方法，用阳极峰电流与阳极峰面 积作为体系抗氧化能力的综合评判指标，并分别针对铂修饰电极和碳 棒修饰电极两种体系建立二元线性方程： Z铀2—0．0969+0．0593Xj+0．121Yt，Rz=0．9990： Z磺*2--0．2275+0．1222X2+0．6543Y2，Rz=0．9881． 4．运用此修饰电极对纯Vc的简单溶液和商品饮料的抗氧化活性进 行初步的测定，并借助传统的Vc检测方法～比色法加以验证，结论是 这两种方法的检测结果一致，进而说明采用电化学方法并借助于修饰 电极进行抗氧化物质活性的检测是可行的。 综上所述，本研究提出了导电高分子掺杂物修饰电极快速测定食 物抗氧化能力新的技术路线和实验方法，并通过实验研究，结合循环 伏安法检测信号的丰富多样性，运用二元线性回归拟合，得到了一种 抗氧化能力多指标综合评价的手段，为深入系统的研究奠定了技术及 理论基础。 关键词：聚吡咯，修饰电极，食品，抗坏血酸，抗氧化能力 儿 浙租：r商人学硕J：学位论义STUDY 浙租：r商人学硕J：学位论义 STUDY ON AN ELECTRoDE FoR DETERMINATIoN oF ANTloXIDANT CAPACITY IN LIQUID FooD CoNTAlNING ASCoRBIC ACID ABSTRACT This paper was based Oil the theory of electro—catalytic oxidation of ascorbic acid on an electrode modified by conductive polymer fihn，the preparation of platinum／kryptol electrode modified by polypyrrole film complexed with ferrocyanide ion was investigated，and electrochemical method for the determination of ascorbic acid with the modified electrode was also discussed in detail．The purpose of this study was to develop an electrode which could fulfill such function as quick determining the antioxidant capacity of liquid food that contains ascorbic acid，to build up an experimental system which called ‘three electrodes of electrochemistry”，and on the basis of these to construct a group of electrodes like this which used to detect some other antioxidants，such as VE(the tocopherols)，carotenoids，polyphenols，flavones，and etc，therefore， with the help of groups of electrodes，the total antioxidant capacity(TAC) of liquid food system composed of complex components could be estimated effectively．The results of study showed that： 1．The working electrode WaS modified successfully by means of electro deposition with polypyrrole film or by incorporating ferro