Development and Application of Comprehensive Chemical Analytical Methods for the Analysis of Polyaromatic Compounds

Ewa Małgorzata Skoczyńska

Research output: PhD ThesisPhD Thesis - Research VU, graduation VU

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Abstract

Polycyclic aromatic hydrocarbons (PAHs) and numerous related polyaromatic compounds (PACs), like substituted PAHs or heterocyclic polyaromatics, are a widespread class of organic compounds originating from natural and anthropogenic sources. During the last century the impact of anthropogenic sources on the emission of PACs has been growing substantially. Nowadays, a rising number of man-made chemicals and unintentionally produced compounds enter the environment. Identification of potentially harmful compounds poses a serious challenge because environmental samples are very complex. Additionally, the „chemical picture” of our environment is changing rapidly. Analysis of complex environmental samples with a rich matrix requires efficient and robust extraction, clean-up and/or fractionation procedures followed by gas- or liquid chromatographic analysis. Gas chromatography in combination with mass spectrometry was the method of choice in my research. The study presented here focuses on the developments in the environmental analysis of PACs with the emphasis on the contaminants of emerging concern (CECs), whereas the standard analysis of PAHs still concentrates on the set of so called 16 EPA PAHs, set in 1976. My research concentrated on the analysis of PACs in complex matrices like sediment and recycled rubber. The developed methods combine target analysis, based on a predefined list of analytes, and screening analysis, aiming at the identification of unrecognized or novel contaminants. These procedures allowed to isolate, identify and quantify a suite of non-priority pollutants, predominantly PACs, present as complex mixtures. The compounds positively identified (with injection of standards) or tentatively identified (with library search) included inter alia a variety of alkylated PAHs, NSO-heterocycles, NSO-substituted PAHs, halogenated-PAHs, and others. Environmental samples, like polluted sediments, contain thousands of compounds that cannot be chromatographically resolved. In chapter 2, an extract of highly polluted sediment from the river Elbe (Czech Republic) was submitted to non-invasive fractionation, and analysed by comprehensive two-dimensional gas chromatography (GCxGC) coupled with a time-of-flight (ToF) detector (GCxGC-ToF-MS). More than 400 compounds, including chlorinated polycyclic aromatic hydrocarbons (PAHs), alkylated PAHs, quinones, aminoquinones, dinaphthofurans, and thiaarenes were tentatively identified. In chapter 3, a GCxGC method was developed with which methylated PAHs were quantified in river Elbe sediment. The use of different columns, acting according to different separation principles, in addition to specific extraction and clean-up procedures offers solutions for specific targeted analysis. This approach, using GC-columns with different stationary phases and, therefore, different separation mechanisms, was applied in the analysis of alkylated PAH isomers. The stationary phases used in this research included non-polar and semi-polar siloxane-based phases, liquid crystal and ionic liquid phases. Some of these new phases like the new ionic liquid stationary phase, 1,12-di(tripropylphosphonium) dodecane bis(trifluoromethanesulfonyl)imide (SLB®-ILPAH) intended for the separation of PAH mixtures, were studied in chapter 4. Chapter 5 is devoted to the development of a method that would allow identification and quantification of a very wide range of organic compounds extractable from this complex rubber matrix. The obtained results emphasize the need for including a much wider selection of compounds in the analysis and toxicological profiling of crumb rubber. With this research we have gained evidence that the environmental analysis, based on targeted monitoring of a defined list of chemicals controlled by legislation, leaves other emerging contaminants or simply unidentified toxic compounds outside the analytical scope. The developed analytical methods and new analytical approaches facilitate the identification of contaminants of emerging concern, their sources and associated toxicological risks. Environmental monitoring requires a more holistic approach than a standard methodology based on a target analysis only.
Original languageEnglish
QualificationMPhil
Awarding Institution
  • Vrije Universiteit Amsterdam
Supervisors/Advisors
  • de Boer, Jacob, Supervisor
  • Murk, Tinka, Supervisor, External person
  • Leonards, PEG, Co-supervisor
Award date20 Jan 2021
Place of Publications.l.
Publisher
Print ISBNs978-94-6423-076-5
Publication statusPublished - 20 Jan 2021

Keywords

  • polyaromatic compounds
  • polycyclic aromatic hydrocarbons
  • contaminants of emerging concern
  • NSO-heterocycles
  • gas chromatography
  • two-dimensional gas chromatography
  • environmental samples
  • environmental analysis
  • screening analysis

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