Development of an analytical method to determine oxy-PAHs and PAHs in Taxus baccata leaves.

An analytical method was developed and optimized for the quantification of 16 polycyclic aromatic hydrocarbons (PAHs) and 12 oxygenated PAHs in Taxus baccata leaves. Emphasis was given to the development of an in-cell cleanup step using pressurized solvent extraction, a cleanup step using solid-phase extraction, and the instrumental analysis by GC-HRMS. Different extraction temperatures (between 50 and 200 °C) and Florisil quantities were evaluated for the extraction process. Based on the evaluation of both recoveries and matrix effect factors, a temperature of 200 °C and 1 g Florisil was selected as the optimum. However, the in-cell cleanup was not sufficient in the long term due to increasing chromatographic peak broadening, and further cleanup was necessary. Solid-phase extraction (using Florisil) was evaluated, and breakthrough curves were acquired for all target compounds to determine the optimal elution volume and avoiding matrix interference. Recoveries of the target compounds ranged from 58 to 87 % for the PAHs and from 5 to 105 % for the oxy-PAHs. Matrix effects were determined for all individual target compounds. The optimized method was applied to T. baccata samples obtained from ten sampling locations in Ghent, Belgium. This is the first biomonitoring study in Ghent for PAHs and oxy-PAHs. The presence of significant amounts of toxicologically relevant oxygenated PAHs (Oxy-PAHs) (can enhance ROS formation in human lung cells) in T. baccata was confirmed (max ∑Oxy-PAHs: 230 ng/g; max ∑PAHs: 389 ng/g). This means that these oxygenated PAHs are important pollutants and should be included in future monitoring studies.