Quantification of Benzo[a]pyrene in Olive Oil and Its Uncertainty Evaluation

Abstract

Benzo[a]pyrene, a polycyclic aromatic hydrocarbon (PAH), is commonly formed by incomplete combustion and widely found in various environmental media and foods. Due to its carcinogenicity, regulatory restrictions have been issued all over the world limiting its concentration in air and food. Consequently, the Consultative Committee for Amount of Substance of the International Community for Weights and Measures (CIPM-CCQM) conducted an international key comparison study (CCQM-K146) for the quantification of benzo[a]pyrene in olive oil. For CCQM-K146, the National Metrology Institute of Japan (NMIJ/AIST) extracted benzo[a]pyrene with dimethyl sulfoxide, then purified it with gel permeation chromatography and silica-gel, and finally measured with GC-MS, using ¹³C₄-benzo[a]pyrene as an internal standard. The obtained result was 2.79±0.17 μg kg⁻¹ (value ± expanded uncertainty, k = 2.78), with the largest uncertainty component originating from the calibration solution used, followed by the weighing of the calibration solution and the dilution of the surrogate solution. Our results were comparable to those of other national metrology institutes.