Determination of benzo(a)pyrene by GC/MS/MS in retail olive oil samples available in Qatar

Abstract

A survey was carried out for the presence of benzo(a)pyrene (B(a)P) in olive oils following reports that some batches of Spanish olive–pomace oil and its products contained high levels of B(a)P. Three types of olive oils (1) virgin olive oil, (2) refined olive oil and (3) olive–pomace oil, originating from France, Greece, Italy, the Lebanon, Spain, Tunisia and Turkey, and available on Qatar market, were analysed for B(a)P. Determination was carried out by extraction from a cyclohexane solution with N,N-dimethylformamide: water (9:1), back extraction with cyclohexane, followed by clean-up on a silica gel column and quantification by GC/MS/MS. The recovery and limit of quantitation of B(a)P in olive oils by this method were estimated as 88% and 0.5 μg kg⁻¹, respectively. B(a)P was detected in amounts below the permitted level of 2 μg kg⁻¹ in all 31 virgin olive oil samples and in 13 refined olive oil samples. However, all seven samples of Spanish olive–pomace oil produced and packed in Spain and three samples of olive–pomace oil produced in Spain, but packed in Saudi Arabia, were found to be contaminated with B(a)P, the level ranging from 3.1 to 70.8 μg kg⁻¹. In two samples of olive–pomace oil originating from Greece, B(a)P was not detected.

Keywords:

• benzo(a)pyrene
• olive–pomace oil
• GC/MS/MS
• polycyclic aromatic hydrocarbons