维生素K_3的电化学研究

Study on Electrochemical Behavior of Vitamin K 3

采用单扫示波极谱法，ＶＫ３在０．１ｍｏｌ／ＬＮａＣｌ底液中，于－０．４６Ｖ（ＳＣＥ）处有一良好的二阶导数峰，峰高与浓度在５×１０－７～２×１０－５ｍｏｌ／Ｌ范围内成线性关系，检测限为２．５×１０－７ｍｏｌ／Ｌ．当ｐＨ值小于３．６０时，ＶＫ３与氢离子作用，于零伏左右有一准可逆的２ｅ－＋Ｈ＋波；当ｐＨ值大于３．６０时，用低扫速的卷积伏安法观察，可发现ＶＫ３有双锋，说明有反应中间体存在，在水合介质中其反应机理是可逆的逐级双电子过程．此外，还对底液中溶解氧的影响进行了讨论．

Vitamin K 3 (menadione) shows a sensitive 2nd order derivative reduction wave with the potential of-0.46V(SCE) in the medium of 0.1mol/L NaCl (pH=4.35) by single sweep oscillopolarography. In the range from 5×10 7 ～2×10 5 mol/L, the peak height of menadione depends linearly on the concentration and the detection limit is 2.5×10 -7 mol/L. Menadione reacts with hydrogen ion at pH<3.60 and produces at about o volt a quasi reversible 2e -+H + wave. In the pH range from 3.60 to 9.26,the electrode process is a reversible multistep charge transfer process. It is proved that there is the reactive intermediate in this pH range by convolution voltammetry. In addition,the effect of dissolved oxygen in this base solution electroreduction of menadione is discussed.