Rapid and complete extraction of phenols from olive oil and determination by means of a coulometric electrode array system

Extraction methods to determine olive oil phenols are not exhaustive. A pro cedure to test their effectiveness, based on the treatment of the extracted oil with 2 N HCl followed by analysis of phenols in the aqueous phase, has been developed. It was concluded, using this test, that 15-40% of phenols remained unextracted when the liquid/liquid extraction method with 80% meth anol was applied. Solid phase extraction (C-18 cartridge) succeeded in reta ining most of the phenols in the cartridge, but the recovery yield from the sorbent material was low. However, a new extraction method, based on the u se of N,N-dimethylformamide (DMF) as an extraction solvent, achieved a comp lete extraction of phenols from oils. The proposed method requires a lower amount of oil, solvents, energy, and labor than the traditional ones. Becau se of the low concentration of phenols in the DMF extract, the highly sensi tive electrochemical detector (EC) technique was studied; All of the phenol s detected by the traditional UV detectors were also detected by EC using a coulometric array system. A rapid and complete analytical methodology. of phenols in olive oil has been proposed based on coupling DMF extraction and EC detection.