Searching ingredients polluted by polycyclic aromatic hydrocarbons in feeds due to atmospheric or pyrolytic sources

► The proposed methods are useful for PAHs fate in feeds and feed ingredients. ► PAHs pollution in feeds is mainly due to their fibre content. ► PCA analysis was helpful to show which other ingredients are causing contamination by PAHs in feeds. ► Feeds can be separated by contamination occurring by pyrolytic or atmospheric sources. ► Toxicity equivalent quantities (TEQ) reached a maximum of 1.1μg/kg for feeds and 11 for feed ingredients. The primary aim of the proposed work is to propose the potential sources of pollution by polycyclic aromatic hydrocarbons (PAHs) in feeds and ingredients. To reach this propose the development of a simple, fast, quantitative and economic method for determining PAHs using liquid-liquid extraction (LLE), clean-up and detection by liquid chromatography with fluorescence detection (LC-FD) in polluting feeds and ingredients was developed. The overall method quantification limits range from 0.020 to 4.0μg/kg and analyte recoveries are between 70% and 105% with relative standard deviations (RSD) lower than 20%. Molecular patterns of PAHs were used to study their distribution in the selected samples by cluster analysis, separating them in two groups: contaminated by atmospheric or pyrolytic sources. In order to find a relationship between the nutritional composition (protein, fibre, ash and fat content), and the hypothetical toxicity of selected feeds, a partial least squared (PLS) analysis was used, showing that fibre was a major contributor. Moreover, the complete data set of 27 feed samples and 25 feed ingredients x 13 PAH concentrations were analysed by PCA to find out what ingredients were controlling PAH pollution.