光电化学制备普鲁士蓝电极及维生素B6的测定

在1.0×10-2 mol.L-1的亚硝基铁氰化钠溶液中,在光辐射下利用循环伏安法制备了一种蓝色薄膜修饰电极。XRD粉末衍射和红外光谱研究表明,该蓝色薄膜为普鲁士蓝。电化学研究表明该膜的电子传递系数为0.48,表观电子转移速率常数为0.43 s-1。在pH=3.0的条件下,该修饰电极的峰电流与维生素B6浓度在7.29×10-5 mol.L-1～1.22×10-3 mol.L-1范围内呈良好的线性关系,相关系数为R=0.999 4,检出限为4.86×10-5 mol.L-1。干扰实验表明,7.29×10-2 mol.L-1的共存葡萄糖、果糖、维生素B2和维生素B12不干扰维生素B6的测定。对实际样品的测定,5次测量的平均回收率为93.7%。

Photoelectrochemical preparation of Prussian blue electrode under irradiation and determination of vitamin B_6

A blue thin film was obtained from 1.0×10-2 mol·L-1 sodium nitroprusside under irradiation with cyclic voltammetry.The measurements of X-ray powder diffraction and FT-IR spectroscopy confirmed the blue film is Prussian blue.The voltammetric studies show that the electron transfer coefficient is equal to 0.48,and the apparent electron transfer rate constant（ks） between the electrode and the film is 0.43 s-1.Further studies display that this electrode can oxidize vitamin B6 electro-catalytically,a linear relationship appearing between the peak current and the vitamin B6 concentration from 7.29×10-5 mol·L-1 to 1.22×10-3 mol·L-1 with R=0.999 4,and that the detection limit is 4.86×10-5 mol·L-1.Interference tests show that glucose,fructose,vitamin B2 and vitamin B12 with their concentration of 7.29×10-2 mol·L-1 do not bring interference signal in the determination of vitamin B6.A mean recovery is equal to 93.7% based on the results of 5 real samples.