Polycyclic aromatic hydrocarbons (PAH) are well known contaminants in food. Their mutagenic and carcinogenic effects lead to significant human health risk. 
However the oxidized form of PAHs (oxy-PAH) and the nitrogen containing polycyclic aromatic compounds (N-PAC) have rarely been researched so far. There have been no thorough studies of the occurrence, stability, dissemination, or potential risk.
Therefore coconut oil, as well as fumigated and barbecued products were examined for oxy-PAHs and N-PACs. So we established two sample preparation methods, size exclusion chromatography (SEC) and dispersive SPE. Tandem mass spectrometry (GC-MS/MS) was implemented for the detection and quantification of these analytes by using deuterated PAHs as internal standards.
Our results indicate the presence of oxy-PAHs in low cost coconut oil, as well as smoked and barbecued products. N-PACs were only found in barbecued products. The distribution of the main detected substances in the individual product groups reveal different formation processes or contamination sources. Moreover the amount of oxy-PAHs was not always comparable to the amount of PAHs.
 Tsutomu Shimada (2004): Metabolic activation of polycyclic aromatic hydrocarbons to carcinogens by cytochromes P450 1A1 and1B1. In: Cancer Sci, vol. 95, no 1, 1-6.