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Abstract
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A new method based on simultaneous derivatization and air-assisted liquid–liquid microextraction
(AALLME) is developed for the determination of some phenolic compounds in different oils. In this
method, the analytes are extracted from the oil samples by NaOH solution, then a few mL of butyl
chloroformate and carbon tetrachloride are injected into the NaOH solution containing the extracted
analytes, and the resulting mixture is sucked into a syringe and injected several times into a test tube
with a conical base. After centrifugation of the resulting cloudy solution, the fine droplets of the organic
phase containing the derivatized phenols are precipitated at the bottom of the tube. Then, 1 mL of the
settled phase is injected into a gas chromatograph with flame ionization detection (GC-FID). The effects
of extraction solvent type, derivatization agent and extraction solvent volumes, number of extractions
and reaction time on the extraction efficiency were investigated. Under the optimum conditions, the
enrichment factors (EF), extraction recoveries (ER), and enhancement factors (EnF) were high and ranged
between 572–991, 60–109%, and 497–1471, respectively. The calibration graphs were linear in the
concentration range of 3–10 000 mg L1. Relative standard deviations (RSD, %) for the extraction of each
of the selected phenols were in the ranges of 2–4% for intra-day (n ¼ 6) and 3–5% (n ¼ 5) for inter-day
precision for a concentration of 200 mg L1 of each analyte. Limits of detection (LOD) were in the range
of 1–2 mg L1. Various oil samples, including olive oil, virgin olive oil, sunflower oil, and colza oil, were
successfully analyzed by the proposed method.
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