Cathodic stripping voltammetric measurements of cholesterol following adsorptive preconcentration at the static mercury drop electrode

AbstractA new electrochemical method for direct measurement of cholesterol by cathodic stripping voltammetry is presented. The method is based on controlled adsorptive preconcentration at the static mercury drop electrode, followed by differential pulse voltammetric determination, in which adsorbed cholesterol reduces and shows stripping current at ca. −1.04 V (versus Ag/AgCl). The current was linear with the cholesterol concentration in the range of 0.2–8 μM. The detection limit found was 0.02 μM (10 minute preconcentration), and the relative standard deviation (at 0.6 μM level) 4.6%. Cyclic voltammetry was used to explore the adsorptive and electrochemical behavior. The adsorptive stripping response was evaluated with respect to preconcentration time, concentration dependence solution, stripping model, possible interference, and other variables. Applicability to serum analysis was illustrated.