DES as a green extracting media for antioxidants electrochemical quantification in extra-virgin olive oils

A new electroanalytical method has been developed for the determination of phenolic compounds in extra virgin olive oils. This method is based on the extraction of phenolic compounds from EVOO with DES and their determination by GC/MWCNT/TiO2 electrode, whose sensitivity is based on the use of MWCNT and TiO2 nanoparticles as modifiers and Nafion as binders on the GCE. This built platform has shown very good sensitivity in detecting phenolic compounds in EVOO at a fairly wide range of concentrations. The measurements were performed by using square wave voltammetry. By using this method, we were able to divide antioxidants in two groups: the group of compounds oxidizing at about 220 mV (1st Group) was the mixture of CA and gallic acid (GA), while for the group oxidizing at about 570 mV (2nd Group) the mixture contained VA, p-Coumaric Acid (p-CA) and tyrosol (TS). The extraction could be performed without using organic solvents and the detection limits for CA and VA were found to be 1.82 and 5.32 µmol/L with GCE, whilst 0.6 and 1.03 µM with GC/MWCNT/TiO2. Based on the results compared with the spectrophotometric method we can say that this method can be used in the determination of phenolic compounds in EVOO