Polycyclic aromatic hydrocarbons, water

With stringent precautions to avoid the presence of water, polycyclic aromatic hydrocarbons show two one-electron reversible waves on cyclic voltammetry in dimethylformamide (Table 7.1). These are due to sequential one-electron additions to the lowest unoccupied molecular n-orbital [1]. Hydrocarbons with a single benzene ring are reduced at very negative potentials outside the accessible range in this solvent. Radical-anions of polycyclic aromatic hydrocarbons [2] and also alkyl benzenes [3] were first obtained by the action of alkali metals on a solution of the hydrocarbon in tetrahydrofuran. They have been well characterised by esr spectroscopy. The radical-anions form coloured solutions with absorption bands at longer wavelength than the parent hydrocarbon [4,5]. 

See also Immune System Occupational Toxicology Pollution, Water Polycyclic Aromatic Hydrocarbons (PAHs). 

Extraction of soils Water Polycyclic-aromatic hydrocarbons... 

Aromatic solvents or polycyclic aromatic hydrocarbons (PAFI) in water, e.g. can be detected by QCM coated with bulk-imprinted polymer layers. Flere, the interaction sites are not confined to the surface of the sensitive material but are distributed within the entire bulk leading to very appreciable sensor responses. Additionally, these materials show high selectivity aromatic solvents e.g. can be distinguished both by the number of methyl groups on the ring (toluene vs. xylene, etc.) and by their respective position. Selectivity factors in this case reach values of up to 100. 

Sodiiun dodecylsulfate, cetyltrimethylam-monium chloride, sodium cholate, -cyclodextrin dansylated amino acids and polycyclic aromatic hydrocarbons > 45-fold 1% in water the greatest enhancement of fluorescence is that of sodium cholate on pyrene [263]... 

An alternative way of eliminating water in the RPLC eluent is to introduce an SPE trapping column after the LC column (88, 99). After a post-column addition of water (to prevent breakthrough of the less retained compounds), the fraction that elutes from the RPLC column is trapped on to a short-column which is usually packed with polymeric sorbent. This system can use mobile phases containing salts, buffers or ion-pair reagents which can not be introduced directly into the GC unit. This system has been successfully applied, for example, to the analysis of polycyclic aromatic hydrocarbons (PAHs) in water samples (99). 

E. R. Brouwer, A. N. J. Elermans, El. Lingeman and U. A. Th Briknman, Determination of polycyclic aromatic hydrocarbons in surface water by column liquid cliromatogr a-phy with fluorescence detection, using on-line micelle-mediated sample preparation , J. Chromatogr. 669 45-57 (1994). 

Lagadec AJM, DJ Miller, AV Lilke, SB Hawthorne (2000) Pilot-scale subcritical water remediation of polycyclic aromatic hydrocarbon- and pesticide-contaminated soil. Environ Sci Technol 34 1542-1548. 

Although these issues have already been briefly noted, they deserve a few additional comments. For freely water-soluble substrates that have low volatility, there are few difficulties in carrying out the appropriate experiments described above. There is, however, increasing interest in xenobiotics such as polycyclic aromatic hydrocarbons (PAHs) and highly chlorinated compounds including, for example, PCBs, which have only low water solubility. In addition, attention has been focused on volatile chlorinated aliphatic compounds such as the chloroethenes, dichloromethane, and carbon tetrachloride. All of these substrates present experimental difficulties of greater or lesser severity. 

Heitkamp MA, CE Cerniglia (1989) Polycyclic aromatic hydrocarbon degradation by a Mycobacterium sp. in microcosms containing sediment and water from a pristine ecosystem. Appl Environ Microbiol 55 1968-1973. 

National Water Research Institute, Canada Polycyclic Aromatic Hydrocarbons Polychlorinated Biphenyls... 

Sander and wise have proposed a test method to determine the bonding chemistry used to prepare octadecylsiloxane column packings based on the relative retention of three polycyclic aromatic hydrocarbons, benzo[a]pyrene (BaP), phenanthro-phenanthrene (PhPh), and l,2 3,4 5,6 7,8-tetrabenzonaphthalene (TBN) eluted with the mobile phase acetonitrile-water (85 15) [52,67,199,210]. On monomeric phases the test solutes elute in the... 

Many process mixtures, notably fermentations, require sample preconcentration, microdialysis, microfiltration, or ultrafiltration prior to analysis. A capillary mixer has been used as a sample preparation and enrichment technique in microchromatography of polycyclic aromatic hydrocarbons in water.8 Microdialysis to remove protein has been coupled to reversed phase chromatography to follow the pharmacokinetics of the metabolism of acetaminophen into acetaminophen-4-O-sulfate and acetaminophen-4-O-glucu-ronide.9 On-line ultrafiltration was used in a process monitor for Aspergillus niger fermentation.10... 

Torres, E. Tinoco, R., and Vazquez-Duhalt, R., Biocatalytic oxidation of polycyclic aromatic hydrocarbons in media containing organic solvents. Water Science and Technology, 1997. 36(10) pp. 37 4. 

Human exposure to complex mixtures of polycyclic aromatic hydrocarbons (PAH) occurs through inhalation of tobacco smoke and polluted indoor or outdoor air, through ingestion of certain foods and polluted water, and by dermal contact with soots, tars, and oils CO. Methylated PAH are always components of these mixtures and in some cases, as in tobacco smoke and in emissions from certain fuel processes, their concentrations can be in the same range as some unsubstituted PAH. The estimated emission of methylated PAH from mobile sources in the U.S. in 1979 was approximately 1700 metric tons (2). The occurrence of methylated and unsubstituted PAH has been recently reviewed (1, 2). In addition to their environmental occurrence, methylated PAH are among the most important model compounds in experimental carcinogenesis. 7,12-Dimethylbenz[a]anthracene, one of... 

Kamlet, M. J., Doherty, R. M., Carr, P. W., Mackay, D., Abraham, M. H., Taft, R. W. (1988) Linear solvation energy relationships. 44. Parameter estimation rules that allow accurate prediction of octanol/water partition coefficients and other solubility and toxicity properties of polychlorinated biphenyls and polycyclic aromatic hydrocarbons. Environ. Sci. Technol. 22, 503-509. 

May, W. E., Wasik, S. P., Freeman, D. H. (1978b) Determination of the solubility behavior of some polycyclic aromatic hydrocarbons in water. Anal. Chem. 50, 997-1000. 

Wang, L., Wang, X., Xu, O., Tian, L. (1986) Determination of the ra-octanol/water partition coefficients of polycyclic aromatic hydrocarbons by HPLC and estimation of their aqueous solubilities. Huanjing Kexue Xuebao 6, 491 497. 

Baker, J.E., Eisenreich, S J. (1990) Concentrations and fluxes of polycyclic aromatic hydrocarbons and polychlorinated biphenyls across the air-water interface of Lake Superior. Environ. Sci. Technol. 24, 342-352. 

Broman, D., Naf, C., Rolff, C., Zebuhr, Y. (1991) Occurrence and dynamics of polychlorinated dibenzo-p-dioxins and dibenzofurans and polycyclic aromatic hydrocarbons in the mixed surface layer of remote coastal and offshore waters of the Baltic. Environ. Sci. Technol. 25, 1850-1864. 

De Maagd, P.G.-J., ten Hulscher, T.E.M., Van den Heuvel, H., Opperhuizen, A., Sijm, D.T.H.M. (1998) Physicochemical properties of polycyclic aromatic hydrocarbons aqueous solubilities, n-octanol/water partition coefficients, and Henry s law constants. Environ. Toxicol. Chem. 17, 252-257. 

Eadie, B.J., Landrum, P.F., Faust, W. (1982) Polycyclic aromatic hydrocarbons in sediments, pore water and the amphipodPontoporeia hoyi from Lake Michigan. Chemosphere 11(9), 847-858. 

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