Separation, detection and identification of phase I and phase II metabolites and their corresponding polycyclic aromatic compounds

Abstract

Polycyclic aromatic compounds (PACs) are transformed into polar metabolites in environmental matrices. These metabolites are rarely included in risk assessments, although they contribute to the toxicity of PAC pollutants including mineral oil spills. Phase I and phase II PAC metabolites hold physical and chemical properties different from those of the PACs, and hence analytical methods covering a wider range of properties are needed. We present an analytical protocol for the separation, detection, quantification and identification of PACs and their polar metabolites. This protocol includes a variety of extraction techniques: separation using GC and reversed phase LC systems; and detection of the compounds by fluorescence-, ultra-violet diode-array-, and high resolution tandem mass spectrometry detectors. These complementary sets of information allow for compound quantification and tentative identification. In the cases where authentic standards or a priori knowledge is available, this leads to compound identification. The approach was applied in two studies where either (1) the soil fungus Cunninghamella elegans, or (2) the marine invertebrate Nereis diversicolor was exposed to PACs. The protocol is a valuable tool for the exploratory and quantitative analysis of formed phase I and phase II metabolites as well as the corresponding un-substituted and alkyl-substituted PACs from a variety of sample matrices: fungi, polychaetes, sediment, soil and water.