مشخصات پژوهش

Many phenolic compounds and their conversion products are hazardous to human health. Therefore the US Environmental Protection Agency regulated 11 phenols among the main environmental pollutants [1]. In addition to being highly toxic and potential carcinogen, these compound causes, even at very low concentration, adverse effects on the central nervous system, cardiovascular system, lungs, kidney, and liver [2]. So finding a rapid and simple analytical method as well as high accuracy in the identification and quantitation of the phenolic compounds is necessary to monitor and regulate their usage for ensuring food quality and safety. Several sample preparation methods have been developed for the extraction and preconcentration of phenols such as liquid–liquid extraction (LLE), solid-phase extraction, supercritical-fluid extraction, microwave-assisted extraction, and dispersive liquid–liquid microextraction prior to their determination by analytical instruments. Recently a new sample preparation technique namely air–assisted liquid-liquid microextraction (AALLME) has been introduced by Farajzadeh [3]. In this study, AALLME method combined with LLE has been developed as a new approach for simultaneous derivatization, extraction and preconcentration of some phenolic compounds in vegetable oils prior to GC-FID and GC-MS determinations. The proposed method consists of two steps: (i) extraction of phenols from vegetable oils by LLE; and (ii) simultaneous derivatization and enrichment of the phenols by AALLME. In the first step, phenolic compounds are extracted into NaOH (0.5 M) followed by AALLME (second step). Under the optimum conditions, the method showed wide linear ranges (2.7-10000 µg L-1). Enrichment factors were in the ranges of 568 to 1128. Relative standard deviations for the extraction of 200 µg L-1 of each selected phenols were between 1.7- 4.3%. The method was successfully applied to analytes determination in olive oil, sunflower oil, and kolza oil.