Simultaneous analysis of 10 polycyclic aromatic hydrocarbons in roasted coffee by isotope dilution gas chromatography-mass spectrometry: Optimization, in-house method validation and application to an exploratory study

Abstract

The presence of polycyclic aromatic hydrocarbons (PAHs) in food implies a potential risk to human health. Although the coffee has been appointed as an important matrix to be monitored for contamination by PAHs, there is still a gap in the literature regarding to the methods of analysis appropriately validated for this scope and also related to the occurrence of contamination in Brazilian commercial samples. In this paper, a method for the determination of ten priority PAHs in roasted coffee by isotope dilution gas chromatography coupled to mass spectrometry was optimized, validated and applied to an exploratory study with 24 commercial samples. The samples were extracted with simultaneous clean-up using pressurized liquid extraction (PLE), followed by liquid–liquid extraction (LLE) and clean-up using silica columns. Linearity was obtained in the concentration range from 0.25 to 4.00 μg kg−1. Matrix effects were not significant. The precision was demonstrated with relative standard deviations varying from 3.3 to 24 % under repeatability and from 3.3 to 33 % under intermediate precision conditions. The average recovery values ranged between 87 and 111%. These values, as well as the limits of detection, limits of quantification and uncertainties of measurements, met the performance criteria established by European Union regulations. The contamination of the commercial samples ranged from 1.00 ± 0.35 to 11.29 ± 2.33 μg kg−1, indicating the need of further occurrence studies and establishment of monitoring programs in Brazil.