胆固醇的吸附氧化及差示脉冲伏安测定

DIFFERENTIAL PULSE VOLTAMMETRIC MEASUREMENTS OF CHOLESTEROL BASED ON ITS OXIDATION AFTER ADSORPTION AT THE MERCURY ELECTRODE

胆固醇能在开路下吸附在悬汞电极的表面,并在电位扫描过程中发生氧化。在0.1 mol/LK_2HPO_4—KH_2PO_4缓冲溶液(pH 7.8)中,差示脉冲溶出峰电位在-0.08V,溶出电流与胆固醇浓度在10^(-7)～10^(-6)mol/L范围内呈线性关系。经5min富集,检测下限达8×10^(-8)mol/L。本文对胆固醇在电极上的吸附、氧化机理,测定条件和干扰情况进行了探讨,并提出了直接测定血清中游离胆固醇的方法。

Cholesterol can be adsorbed on the surface of the static mercury drop electrode, and then oxidized during anodic potential scan. The stripping peak potential in differential pulsevoltammetry is at-0.08 V in 0. 1 mol/L K_2HPO_4--KH_2PO_4 buffer solution. The stripping current islinear with the concentration of cholesterol in the range of 10^(-7)～10^(-6) mol/L. The detection limitfound is 8×10^(-8) mol/L after a 5 min preconcentration period. The adsorption and oxidation mechani-sms of cholesterol at the mercury electrode were been explored. The experimental conditions for mea-suring free cholesterol in human sera were examined.