title: Can two-dimensional gas chromatography/mass spectrometric identification of bicyclic aromatic acids in petroleum fractions help to reveal further details of aromatic hydrocarbon biotransformation pathways?
abstract: BACKGROUND
  The identification of key acid metabolites ('signature' metabolites) has allowed significant improvements to be made in our understanding of the biodegradation of petroleum hydrocarbons, in reservoir and in contaminated natural systems, such as aquifers and seawater. On this basis, anaerobic oxidation is now more widely accepted as one viable mechanism, for instance. However, identification of metabolites in the complex acid mixtures from petroleum degradation is challenging and would benefit from use of more highly resolving analytical methods.
  
  
  METHODS
  Comprehensive two-dimensional gas chromatography/time-of-flight mass spectrometry (GCxGC/TOFMS) with both nominal mass and accurate mass measurement was used to study the complex mixtures of aromatic acids (as methyl esters) in petroleum fractions.
  
  
  RESULTS
  Numerous mono- and di-aromatic acid isomers were identified in a commercial naphthenic acids fraction from petroleum and in an acids fraction from a biodegraded petroleum. In many instances, compounds were identified by comparison of mass spectral and retention time data with those of authentic compounds.
  
  
  CONCLUSIONS
  The identification of a variety of alkyl naphthalene carboxylic and alkanoic and alkyl tetralin carboxylic and alkanoic acids, plus identifications of a range of alkyl indane acids, provides further evidence for 'signature' metabolites of biodegradation of aromatic petroleum hydrocarbons. Identifications such as these now offer the prospect of better differentiation of metabolites of bacterial processes (e.g. aerobic, methanogenic, sulphate-reducing) in polar petroleum fractions.
authors.affiliation: Petroleum and Environmental Geochemistry Group, Biogeochemistry Research Centre, Plymouth University, Drake Circus, Plymouth, PL4 8AA, UK.
authors.forename: Charles E
authors.initials: CE
authors.lastname: West
authors.forename: Jos
authors.initials: J
authors.lastname: Pureveen
authors.forename: Alan G
authors.initials: AG
authors.lastname: Scarlett
authors.forename: Sabine K
authors.initials: SK
authors.lastname: Lengger
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Wilde
authors.forename: Frans
authors.initials: F
authors.lastname: Korndorffer
authors.forename: Erik W
authors.initials: EW
authors.lastname: Tegelaar
authors.forename: Steven J
authors.initials: SJ
authors.lastname: Rowland
mesh_terms: D001673:Biodegradation, Environmental; D008401:Gas Chromatography-Mass Spectrometry / Q000379:methods*; D006841:Hydrocarbons, Aromatic / Q000032:analysis*; D010578:Petroleum / Q000032:analysis*
chemical_list: D006841:Hydrocarbons, Aromatic; D010578:Petroleum