Abstract:

An efficient and simple analytical method has been developed for the determination of 6 phenolic antioxidants, namely 4,4＇isopropylidendiphenol (BPA), tert-butyl-4-hydroxyanisole (BHA), 2,6-di-tert-butyl-4-hydroxy-methylphenol (Ionox100), 2,6-di-tert-butyl-p-cresol (BHT), 2,4,6-tri-tert-butylphenol (TTBP) and 2,2 ＇-methylenebis-(6-tert-butyl-4-ethylphenol) (AO 425) in fatty food simulant olive oil. Two methods, namely extraction with methanol on a vortex mixer followed by concentration using a rotary evaporator (hereinafter referred to as Method 1) and extraction with cyclohexane/ethyl acetate mixture (1:1, V/V) on a vortex mixer followed by gel permeation chromatographic concentration (hereinafter referred to as Method 2) were separately used for sample pretreatment before ultra performance liquid chromatographic (UPLC) analysis. The merits of figure of the developed method were as follows: respective limits of detection (LODs) for BPA, BHA, Ionox100, BHT, TTBP and AO 425, 0.06, 0.04, 0.01, 0.03, 0.06 mg/L and 0.01 mg/L; correlation coefficients of calibration curve of the analytes, larger than 0.998, indicating good linearity; and respective average spike recoveries for the analytes in samples pretreated by Methods 1 and 2, larger than 83.0% and 56.8%, with RSDs of smaller than 7.5% and 8.4%. This method was used to determine some commercial edible oils from different plants, and only BHT was detected in all of them, the contents of which were all much lower than the Chinese national specific migration limit.

Key words: antioxidant, vortex-mixing extraction, gel permeation chromatography (GPC), ultra performance liquid chromatography (UPLC), olive oil