表面活性剂存在下雌激素的直接电化学分析

雌二醇（E2）、雌三醇（E3）和雌酮（E1）是人体内3种重要的雌激素，它们在妇女的生殖生育方面发挥重要的作用。人体雌激素缺乏或过乘会导致诸多疾病。雌激素的检测方法已有不少报道，如气相色谱－质谱（GC－MS）、液相色谱（LC）以及化学发光免疫法等。E2，E1和E3的结构相似，且均具有疏水性及非电活性，用电化学直接测定十分困难，一般只能间接测定。本文报道了一种新的电化学分析方法。该方法对三种雌激素有十分灵敏的伏安响应，可用于微量测定。

Direct Electroanalysis of Estrogen in the Presence of Surfactants

It is difficult to determine estrogens directly by electrochemical methods because estradiol, estrone and estriol are hydrophobic and electroinactive. Thus, they are only determined by the indirect electrochemical techniques. In this paper, based on the voltammetric behavior of estrogens(estradiol, estrone and estriol) on the Nafion-modified glassy carbon electrode in the presence of CTAB, a novel direct electroanalytical method for the determination of the total amounts of estradiol, estrone and estriol was developed. In pH=8.00 phosphate buffer and in the presence of 6×10^-5 mol/L CTAB, estradiol, estrone and estriol have very sensitive oxidation peaks at 0.38 V(vs. SCE) at Nafion-modified glassy carbon electrode after being accumulated for 3 min at -0.50 V. This peak can be used to determine trace level of estradiol, estrone and estriol. It was found that estradol, estrone and estriol have the similar electrochemical responses on the Nafion-modified electrode in the presence of other long-chain cationic surfactants, such as CPB, STAB, CATAB, LTAB. It is observed that the enhancement effect is highest in the presence of CTAB, and the peak current is CTABconcentration-dependent. However, in the presence of long-chain anionic surfactants, such as SDBS, and long-chain nonionic surfactants, such as Triton X-100, estradiol, estrone and estriol have no voltammetric responses on the Nafion-modified glassy carbon electrode. The mechanism for the oxidation of estradiol in this system has been discussed, and the reactant site for the oxidation of estradiol has been verified to be the hyrdoxyl group in A-ring.