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以现场长光程薄层圆二色光谱电化学方法研究了抗坏血酸在玻碳电极上的电极反应过程.通过双对数法和非线性回归的方法处理了薄层圆二色光谱电化学实验数据,结果表明抗坏血酸在pH7.0的缓冲溶液中玻碳电极上为2个电子转移的不可逆电化学氧化,氧化产物在电极上发生了强吸附,吸附层对抗坏血酸的电化学氧化反应有自加速作用,并获得了抗坏血酸在探电极和在吸附电极上的式电位分别为E~(?)=0.09V,E~(?)=0.26V;电子转移数和电子转移系数分别为an=0.41,a_(?)n=0.07;标准复相电子转移速率常数分别为k~0=8.0×10~(-5)cm s~(-1),k~0_a=1.9×10~(-4)cm s~(-1);吸附系数为β=102.6±0.2.
The electrode reaction process of ascorbic acid on glassy carbon electrode was studied by the long optical pathlength thin layer circular dichroism spectroscopic electrochemical method.The experimental data of thin circular dichroism spectroscopy were processed by the method of double logarithm and nonlinear regression The results showed that ascorbic acid was irreversibly electrochemically oxidized by 2 electron transfer on the glassy carbon electrode in buffer solution of pH7.0. The product of oxidation was strongly adsorbed on the electrode, and the electrochemical oxidation of ascorbic acid on the adsorbed layer was accelerated , And the potential of ascorbic acid at the probe electrode and at the adsorbed electrode was respectively E = 0.09V and E = 0.26V; the electron transfer number and the electron transfer coefficient were an = 0.41, a_ (?) n = 0.07; the standard rate of complex electron transfer is k = 0 = 8.0 × 10 -5 cm s -1, k 0 a = 1.9 × 10 -4 cm s ~ (-1); the adsorption coefficient is β = 102.6 ± 0.2.