Cryogenic-zone-compression gas chromatography-mass spectrometry for the determination of 16 polycyclic aromatic hydrocarbons in extra virgin olive oil

The present study is based on the development of a straightforward method for the determination (semi-quantification) of 16 polycyclic aromatic hydrocarbons (PAHs) in extra virgin olive oil (EVOO) using "cryogenic-zone-compression" (CZC) gas chromatography-single quadrupole mass spectrometry (GC-QMS). The use of CZC (through a loop-type cryogenic modulator) to achieve enhanced signal-to-noise ratios (s/n), enabled a simplification of the sample preparation step. In fact, a single extraction process (using only 500 µL of acetonitrile) was performed prior to injection. The CZC GC-QMS method aligns with the principles of green analytical chemistry, and enabled an average s/n increase of 14-fold compared to conventional GC-QMS.

The method limits of quantification were in the 0.07–8.33 µg kg⁻¹ range. Accuracy (at the 2 μg kg⁻¹ and 10 μg kg⁻¹ concentration levels) was in the 82–103 % range. Intra-day and inter-day precision (at 2 μg kg⁻¹ and 10 μg kg⁻¹ concentration levels) were in the 1.9–14.7 % and 5.9–9.1 % ranges, respectively, while the recovery values (at 10 µg kg⁻¹) ranged from 24 % to 99 %. For all the PAHs investigated, a positive matrix effect was observed. Two PAHs were detected (in the selected-ion-monitoring mode) in six EVOOs among the ten samples (not more than one PAH per sample).