Quasi-targeted Qualitative Analysis Of Novel Halogenated Organic Pollutants And Hydroxylation-related Metabolites Of Polycyclic Aromatic Hydrocarbons

Anthropic and natural activities produce multitudinous organic compounds which could find their way into environment and thus pose environmental pollution.Persistent organic pollutants(POPs)are an important group of pollutants which possess the properties of high toxicity,bio-concentration,bio-amplification,persistence and longdistance migration.Besides the halogenated persistent organic pollutants(POPs)studied already,numerous novel,potential and unknown halogenated organic pollutants(HOPs)possibly present in the environment.Prior to further study for these potentially novel HOPs,they should be identified from environmental samples and their significance of environmental research should be preliminarily evaluated.Polycyclic aromatic hydrocarbons(PAHs)are a category of ubiquitous organic pollutants with the properties of persistence,bio-concentration and toxicity,and could be found in human body,particularly for the population who are possibly exposed to PAHs.For better understanding the in vivo metabolic processes and pathways of PAHs,identification of PAH metabolites is the primary requirement.In this study,we proposed the idea and concept of quasi-targeted analysis,and accordingly developed qualitative methods for the identification of novel HOPs in environmental samples and PAH metabolites in human urine.With the developed quasitargeted analysis methods,a series of novel HOPs and PAH metabolites were identified.After identification of these novel HOPs and PAH metabolites,we used the chemical software,based on the theory of quantitative structure-activity relationship(QSAR),to calculate the physicochemical properties and biological activities of these compounds,and predict their various environmental behaviors.This thesis mainly contains the following contents:1.A quasi-targeted analysis method was developed for the identification of novel HOPs in environmental samples.The method development procedures were briefly described as follows: Firstly,the chemical structures,exact molecular weight and theoretical isotopic distribution patterns of the novel HOPs,which are possibly present in the environment,were simulated and obtained with chemical software;Secondly,several isotopic masses of each HOP were scanned with gas chromatography high resolution mass spectrometry(GC-HRMS)using multiple ion detection mode;Thirdly,the similarity between the detected isotopic distribution pattern to the simulated one was evaluated with paired-sample T test of the software SPSS 19.0 and cosine similarity analysis;Lastly,the identified chromatographic peaks were further checked in terms of retention times by referring to the calculated predictive relative retention times and predicted retention time ranges.In addition,this developed method was validated with a variety of HOP reference standards and the unintentionally found impurities of mixchlorinated/brominated benzenes(HXBs)in halogenated benzene standards.The verification data and the actually detected results demonstrate that the method is suitable,practical and reliable for the screening and identification of novel HOPs in environmental samples,such as mixed-halogenated organic pollutants and sulfurcontaining dioxin-like compounds.A quasi-targeted analysis method for the screening and identification of PAH metabolites in human urine was developed by utilizing the multiple reaction monitoring(MRM),precursor ion scan and neutral loss scan modes of liquid chromatography tandem mass spectrometry(LC-MS/MS),the screening in a homemade OH-PAHs metabolites database,and the full scan and product ion scan(MS/MS)of liquid chromatography-quadrupole time-of-flight high resolution mass spectrometry(LCQTOF-HRMS)and liquid chromatography-quadrupole orbitrap high resolution mass spectrometry(LC-Q-Orbitrap-MS).Compared with the untargeted analysis methods reported in literature,the method developed in this study presents higher confirmatory capability and reliability.2.A variety of unreported/scarcely reported novel HOPs were identified in waste incineration fly ash samples.In total 106 molecular formulas of novel HOPs were identified,including 13 formulas of mix-halogenated dioxins/furans(PXDD/Fs),7 formulas of mix-halogenated biphenyls(PXBs),7 formulas of mix-halogenated diphenyl ethers(PXDEs),5 formulas of HXBs,12 formulas of uni-/mix-halogenated naphthalenes(PHNs/PXNs),20 formulas of uni-/mix-halogenated phenanthrenes(HPhes/X-Phes),21 formulas of uni-/mix-halogenated pyrenes(H-Pys/X-Pys),a bromoanisole,a formula of methoxy polybrominated diphenyl ether,3 sulfur-containing dioxin-like HOPs(S-HOPs),13 formulas of halogenated benzonaphthodioxines/furans(HBND/Fs),and 3 formulas of polyhalogenated biphenylenes(PHBPs).Generally,several isomers were observed for most of the identified formulas.Six identified novel halogenated HOPs can be structurally elucidated,namely,1-bromo-2,3,4,5,6-pentachlorobenzene,1,2,3,4,5-pentabromo-6-chlorobenzene,pentabromoanisole,1,2,3,4,6,7,8,9-octachloro-thianthrene,1,2,3,4,6,7,8,9-octachlorophenoxathiine,and 1,2,3,4,6,7,8,9-octachloro-dibenzothiophene.In addition,some formulas with few theoretically possible isomers(2-4)to some extent can be structurally elucidated,in light of the research results in literatures and calculated predictive relative retention times(PRRT).In total,18 compounds were putatively structurally identified,including 1-bromo-2,3,4,6,7,8,9-heptachlorodibenzo[1,4]dioxine,2-bromo-1,3,4,6,7,8,9-heptachloro-dibenzo[1,4]dioxine,1,2,3,4,6,7,8-heptabromo-9-chloro-dibenzo[1,4]dioxine,1,2,3,4,6,7,9-heptabromo-8-chloro-dibenzo[1,4]dioxine,1-bromo-2,3,4,6,7,8,9-heptachloro-dibenzofuran,2-bromo-1,3,4,6,7,8,9-heptachloro-dibenzofuran,3-bromo-1,2,4,6,7,8,9-heptachlorodibenzofuran,4-bromo-1,2,3,6,7,8,9-heptachloro-dibenzofuran,1,2,3,4,6,7,8-heptachloro-9-fluoro-dibenzo[1,4]dioxine,1,2,3,4,6,7,9-heptachloro-8-fluorodibenzo[1,4]dioxine,Br-PCB-206,Br-PCB-207,Br-PCB-208,1,2,3,4,5,6,7-heptachloro-naphthalene(PCN-73),1,2,3,4,5,6,8-heptachloro-naphthalene(PCN-74),Cl-BDE-206,Cl-BDE-207,and Cl-BDE-208.Besides fly ash samples,some other environmental matrices such as soil,sewage sludge,in-door dust,ambient air and fish muscle were screened with the developed quasi-targeted analysis method,and a number of novel HOPs were found in some of these matrices.3.Ultimately,in total 19 types of PAH metabolites were identified and confirmed,including two phase I metabolites and 17 phase II metabolites.The phase I metabolites were PAH dihydrodiols,and the main phase II metabolites were glucuronides and sulfates of hydroxylated PAHs.Some glucuronidation and sulfation metabolites of dihydroxy PAHs were identified also.In addition,a complicated metabolite,phenanthrene dihydrodiol cysteine-glycine was found.The identified metabolites of naphthalene and fluorene are more than those of phenanthrene and pyrene,and only two types of metabolites were found for pyrene which has relatively higher molecular weight.In light of the physicochemical properties and chromatographic behaviors of PAH metabolites,some naphthalene metabolites can be tentatively structurally identified.4.The results of computational simulation indicate that the main identified novel HOPs possess persistence,bio-concentration and toxicity,and are potential environmental pollutants,accordingly meriting environmental research concerns.Most of the identified PAH metabolites are in possession of high polarity,high water solubility,and thus can be excreted with urine readily.In addition,the toxicity of main PAH metabolites is relatively lower compared with the precursor PAHs.However,some PAH metabolites present developmental toxicity and mutagenicity,and thus could negatively affect the human health if remain in human body.The quasi-targeted analysis methods developed in this study have been proved to be suitable for identifying organic pollutants in environmental samples and the metabolites of organic pollutants in biological matrices,particularly for the novel HOPs and the hydroxylated metabolites of POPs.If the corresponding reference standards are unavailable,the methods developed in this study are feasible,reliable and high efficient approaches for the identification of novel HOPs and the in vivo metabolites of organic pollutants.In this study,a series of unreported or scarcely reported novel HOPs in environmental samples and a category of in vivo metabolites of PAHs in human urine have been screened and identified.By means of the available chemical software,some physicochemical properties and biological activities(such as toxicities)of theses identified pollutants and metabolites were calculated and evaluated,and the environmental behaviors of these compounds were also simulated and predicted.These calculated and predicted data are helpful for choosing the identified pollutants and metabolites with high research interests to conduct further studies,such as environmental and toxicological studies.