Determination of tertiary butylhydroquinone in edible vegetable oil by liquid chromatography/ion trap mass spectrometry

A simple, sensitive and accurate analytical method for quantification of tertiary butylhydroquinone (TBHQ) in edible vegetable oil was established by liquid chromatography/ion trap mass spectrometry (LC/ITMS). After extraction, 5 mu l of the extracts was directly injected into LC/ITMS for TBHQ determination. Ethanol was selected as the extraction solvent. The optimized fragmentation amplitude was 1.70 V and electrospray ionization (ESI) was more suitable than atmospheric pressure chemical ionization (APCI) for TBHQ detection. The calibration curve showed good linearity (R-2 = 0.9990) and recoveries from spiked samples ranged from 81.9% to 110.5%. Relative standard deviations of intra-day and inter-day were in the ranges 2.5-5.7% and 3.9-13.8%, respectively. The procedure allows the detection of 0.3 mg/kg TBHQ in edible vegetable oil. Typical edible vegetable oils in the market were detected for TBHQ by the proposed method. As results, TBHQ was detected in blend oil, soybean salad oil and camellia oil samples. (C) 2007 Elsevier Ltd. All rights reserved.