Polycyclic aromatic hydrocarbons (PAHs) determination in cereals and cereal-based products using a modified QuEChERS method with Z-Sep⁺ clean-up and GC-MS/MS quantification

A QuEChERS-GC-MS/MS method for the determination of 4 EU priority PAHs: benzo(a)anthracene, chrysene, benzo(b)fluoranthene, and benzo(a)pyrene in cereals and cereal-derived products was developed and validated. Initially, the GC-MS/MS operation conditions were established, followed by the modified QuEChERS protocol assessed by studying various factors: the extraction salts, the volume of the extract to be purified, the freezing time, and the amounts of Z-Sep⁺ sorbent and MgSO₄. To choose the appropriate protocol, the co-extractive residues (≤0.5 mg/mL) and the extraction recoveries (50-120%, RSD≤15%) were evaluated. The proposed method was validated, and good linearities for standard solutions and matrix-matched food (R²>0.98) were achieved. Matrix effects were ≤±15% for the 4PAHs. Precision, assessed by RSD, varied between 0.8-11.7%, 0.1-13.2%, and 2.1-20.2% in repeatability, reproducibility, and intermediate precision conditions for all PAHs, for 1, 2, 3 μg/kg spiking. Recoveries ranged between 74.1-113.4%. LODs varied between 0.01-0.21 μg/kg, and LOQs from 0.05 to 0.69 μg/kg. The PAH contamination in 96 cereal samples (wheat, triticale, barley, corn) and 18 cereal-based products (flour, bread, semolina, breakfast cereals, biscuits for young children) was investigated using the proposed method. Only chrysene was quantified in 17% of cereal samples, with a content <0.49 μg/kg. In derived products, no PAHs were quantified. • Z-Sep⁺ QuEChERS developed for polycyclic aromatic hydrocarbons (PAH) in cereals. • The method is sensitive for PAH analysis (LOQ ≤ 0,69 µg/kg). • Z-scores of 0.42-1.24 for the 4 PAHs and Σ4PAHs for semolina showed good trueness. • BaP was not quantifiable in the 114 analyzed cereals and derived products. • In cereal-based products from the Romanian market, no PAHs were quantified.