Non-enzymatic electrochemical determination of cholesterol in dairy products on boron-doped diamond electrode

•1st report on direct oxidation of chol. on bare electrode in water-containing media.•Polished glassy carbon and boron-doped diamond electrodes used.•Anodic peak from + 1.2 V to + 1.6 V in acetonitrile/HClO4 depending on water content.•Quantitation of cholesterol in dairy products by DPV combined with LLE.•No significant difference in results obtained by DPV and GC–MS. Determination of cholesterol in food matrices is essential for quality control concerning the health of consumers. Herein, a simple electrochemical approach for cholesterol quantitation in dairy products is evaluated. The newly developed differential pulse voltammetric method using acetonitrile-perchloric acid mixture as a supporting electrolyte is statistically compared to GC–MS and HPLC-UV. Oxidation signals of cholesterol at +1.5 V and +1.4 V (vs. Ag/AgNO3 in acetonitrile) provide detection limits of 4.9 µM and 6.1 µM on boron-doped diamond and glassy carbon electrodes, respectively. A simple liquid–liquid extraction procedure from dairy products into hexane resulted in a recovery rate of (74.8 ± 3.8)%. The method provides results in close agreement (at a 95% confidence level) with GC–MS, while HPLC-UV resulted in a significant difference in estimated cholesterol concentrations for all samples. This newly developed method is a simpler, faster and cheaper alternative to instrumentally demanding MS-based methods and clearly outperforms HPLC-UV.