Development of Analytical Method for Benzo (a) pyrene in edible oil

Abstract

       Benzo(a) pyrene (BaP) is a marker of Polycyclic aromatic hydrocarbons (PAHs) since WHO specifies as carcinogenic to human. Method of analysis for BaP content in edible oil was studied and developed. Liquid-liquid extraction and solid-phase extraction were used to purify sample and HPLC fluorescence detector was used to quantitive analysis of BaP. The result of method validation showed that the developed method is fit-for purpose. Specificity of chromatographic system was shown by retention time of BaP peak at 15.3 min without interference. There are linearity of calibration standards from 1 to 10 ng/ml and linearity of working range from 1 to 10 μg/kg were shown by Pearson’s correlation coefficient (r) of 0.9997 and 0.9996, respectively. Limit of detection (LOD) and limit of quantitation (LOQ) were 0.5 and 1.0 μg/kg, respectively. The recovery of method was studied by spiking standard in olive oil matrix cover the working range, mean recovery was in the range of 81%-86%. Precision was shown by %RSD of repeatability was 3.2-7.4 and within-laboratory reproducibility was 86. The measurement uncertainty of the method showed by % relative standard uncertainty and relative expanded uncertainty were 15.6% and 31.2%, respectively. From 2008-2013, 126 samples of edible oil sold in Thailand were analyzed by the developed method, 34 samples (27.0%) were contaminated by BaP. The level found was ranged from less than 1.0 to 21.6 μg/kg. The results showed that 9 samples (7.1%) of tea seed oil, rice bran oil, raw coconut oil and unlabeled or unspecified oil were contaminated higher than European Commission is Maximum Limit at 2 μg/kg.