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

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 K₂HPO₄--KH₂PO₄ 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.