Determination of synthetic phenolic antioxidants in edible oils using microvial insert large volume injection gas-chromatography

• Microvial insert LVI-GC–MS is proved useful for edible oil analysis.
• Low sample consumption and rapid sample treatment, extraction and clean-up in a single step.
• The procedure provides the best sensitivity to date for the determination of BHA, BHT and TBHQ in edible oils.

Three synthetic phenolic antioxidants, butylated hydroxyanisole (BHA), butylated hydroxytoluene (BHT) and tert-butyl hydroquinone (TBHQ), were determined in different edible vegetable oil samples. The analyses were carried out by gas chromatography–mass spectrometry (GC–MS) using microvial insert large volume injection (LVI). Several parameters affecting this sample introduction step, such as temperatures, times and gas flows, were optimised. Quantification was carried out by the matrix-matched calibration method using carvacrol as internal standard, providing quantification limits between 0.08 and 0.10 ng g–1, depending on the compound. The three phenolic compounds were detected in several of the samples, BHT being the most frequently found. Recovery assays for oil samples spiked at two concentration levels, 2.5 and 10 ng g–1, provided recoveries in the 86–115% range.