Detection of adulteration in cold‐pressed olive oil by voltammetric analysis of alpha‐tocopherol on single‐use pencil graphite electrode

Abstract

SummaryA quick, simple, environmentally friendly and cost‐effective screening approach for identifying parameters of adulteration in cold‐pressed olive oil (CPOO) was developed. The technique focused on the electrochemical examination of the peak of alpha‐tocopherol oxidation on pencil graphite electrode (PGE). Rapeseed oil (RO), sunflower oil (SO), and corn oil (CO) were added to local CPOO in varying amounts, and the mixtures were then tested by differential pulse voltammetry (DPV) on PGE. Voltammetric analysis of CPOO and its artificially created mixtures with other commercial oils have demonstrated statistically significant discrimination with an ability to detect adulteration under the level of 10% on weight basis. The method's relative standard deviation (RSD) was 20%, and the α‐tocopherol in CPOO cut‐off value was 30.98 ± 12.57 nA. As far as our knowledge, no data on utilisation of voltammetric techniques for the detection of olive oil adulteration are available to date by using PGE. The results showed that the developed method is capable of detection of adulteration in natural olive oils without any pretreatment.