Polynuclear aromatic hydrocarbons concentrations

Heit, M., C.S. Klusek, and K.M. Miller. 1980. Trace element, radionuclide, and polynuclear aromatic hydrocarbon concentrations in Unionidae mussels from northern Lake George. Environ Sci. Technol. 14 465A68. 

Genotoxic potential is correlated with polynuclear aromatic hydrocarbon concentration. 

This test method covers the determination of the total amounts of monoaromatic and polynuclear aromatic hydrocarbon compounds in motor diesel fuels, aviation turbine fuels, and blend stocks by supercritical fluid chromatography (SFC). The range of aromatics concentration to which this test method is applicable is from 1 to 7S mass %. The range of polynuclear aromatic hydrocarbon concentrations to which this test method is applicable is from O.S to SO mass %. 

Standardization. Standardization in analytical chemistry, in which standards are used to relate the instrument signal to compound concentration, is the critical function for determining the relative concentrations of species In a wide variety of matrices. Environmental Standard Reference Materials (SRM s) have been developed for various polynuclear aromatic hydrocarbons (PAH s). Information on SRM s can be obtained from the Office of Standard Reference Materials, National Bureau of Standards, Gaithersburg, MD 20899. Summarized in Table VII, these SRM s range from "pure compounds" in aqueous and organic solvents to "natural" matrices such as shale oil and urban and diesel particulate materials. 

Another useful standard Is SRM 1647, priority pollutant polynuclear aromatic hydrocarbons (in acetonitrile). It can be used to calibrate liquid chromatographic Instruments (retention times. Instrument response), to determine percent recoveries, and to fortify aqueous samples with known PAH concentrations. Figure 8 Illustrates the HPLC separation and UV detection (fluorescence is also used extensively) for the 16 priority pollutants. 

The van t Hoff equation also has been used to describe the temperature effect on Henry s law constant over a narrow range for volatile chlorinated organic chemicals (Ashworth et al. 1988) and chlorobenzenes, polychlorinated biphenyls, and polynuclear aromatic hydrocarbons (ten Hulscher et al. 1992, Alaee et al. 1996). Henry s law constant can be expressed as the ratio of vapor pressure to solubility, i.e., pic or plx for dilute solutions. Note that since H is expressed using a volumetric concentration, it is also affected by the effect of temperature on liquid density whereas kH using mole fraction is unaffected by liquid density (Tucker and Christian 1979), thus... 

Munch, D. 1993. Concentration prohles of arsenic, cadmium, chromium, copper, lead, mercury, nickel, zinc, vanadium and polynuclear aromatic hydrocarbons (PAH) in forest soil beside an urban road. Sci. Total Environ. 138 47-55. 

Mix, M.C. and R.L. Schaffer. 1983b. Concentrations of unsubstituted polynuclear aromatic hydrocarbons if bay mussels (Mytilus edulis) from Oregon, USA. Mar. Environ. Res. 9 193-209. 

Murphy, D.J., R.M. Buchan, and D.G. Fox. 1982. Ambient particulate and benzo[a]pyrene concentrations from residential wood combustion, in a mountain community. Pages 567-574 in M. Cooke, AJ. Dennis, and G.L. Fisher (eds.). Polynuclear Aromatic Hydrocarbons Physical and Biological Chemistry. Battelle Press, Columbus, OH. 

The analysis of organosulphur compounds has been greatly facilitated by the flame photometric detector [2], Volatile compounds can be separated by a glass capillary chromatographic column and the effluent split to a flame ionization detector and a flame photometric detector. The flame photometric detector response is proportional to [S2] [3-6]. The selectivity and enhanced sensitivity of the flame photometric detector for sulphur permits quantitation of organosulphur compounds at relatively low concentrations in complex organic mixtures. The flame ionization detector trace allows the organosulphur compounds to be referenced to the more abundant aliphatic and/or polynuclear aromatic hydrocarbons. 

There are indications that pure naphthalene (a constituent of mothballs, which are, by definition, toxic to moths) and alkylnaphthalenes are from three to 10 times more toxic to test animals than are benzene and alkylbenzenes. In addition, and because of the low water solubility of tricyclic and polycyclic (polynuclear) aromatic hydrocarbons (i.e., those aromatic hydrocarbons heavier than naphthalene), these compounds are generally present at very low concentrations in the water-soluble fraction of oil. Therefore, the results of this smdy and others conclude that the soluble aromatics of crude oil (such as benzene, toluene, ethylbenzene, xylenes, and naphthalenes) produce the majority of its toxic effects in the enviromnent. 

To determine the concentrations of benzene, toluene, ethylbenzene, and xylenes, approved methods (e.g., EPA SW-846 8021B, SW-846 8260) are not only recommended but are insisted upon for regulatory issues. Polynuclear aromatic hydrocarbons (PAHs) may be present in condensate, and evaluation of condensate contamination should include the use of other test methods (EPA SW-846 8270, SW-846 8310) provided that the detection limits are adequate to the task of soil and groundwater protection. Generally, at least one analysis may be required for the most contaminated sample location from each source area. Condensate releases in nonsensitive areas require analysis for naphthalene only. The analysts should ensure that the method has detection limits that are appropriate for risk determinations. 

Supercritical fluid extraction (EPA 3540, for total recoverable petroleum hydrocarbons EPA 3561 for polynuclear aromatic hydrocarbons) is applicable to the extraction of semivolatile constituents. Supercritical fluid extraction involves heating and pressuring a mobile phase to supercritical conditions (where the solvent has the properties of a gas and a liquid). The supercritical fluid is passed through the soil sample, and the analytes are concentrated on a sorbent or trapped cryogenically. The analytes are eluted with a solvent and analyzed using conventional techniques. Carbon dioxide is the most popular mobile phase. 

According to the vendor, the technology can effectively treat almost aU hydrocarbons (inclnd-ing gasoline, crnde oil, diesel fnel, and jet fnel), pentachlorophenols, polychlorinated biphenyls, benzene, tolnene, ethyl benzene, xylene, polynuclear aromatic hydrocarbons, trichloroethylene, trichloroethane, and suspended solids. The granules can also be used to remove vegetable-based oils and fats. Another technology advantage is the ability of the SFC system to remove oil emulsified in water to concentrations less than 15 mg/hter. 

Smith, D. J. T., and R. M. Harrison, Concentrations, Trends, and Vehicle Source Profile of Polynuclear Aromatic Hydrocarbons in the U.K. Atmosphere, Atmos. Environ., 30, 2513-2525 (1996). 

Organic contaminants. The concentration of polynuclear aromatic hydrocarbons (PAH) in the particulate phase of flue gases of oil-shale-combusting thermal power plants has been estimated to range from 0.04 to 3.16 mg/m3 (Aunela et al. 1995). The solvent-extractable fraction (<1.5 wt%) from fly ash particles collected from Narva power plant smog chambers included several PAHs (phenanthrene,... 

Lane, W. F., and R. C. Loehr, Estimating the equilibrium aqueous concentrations of polynuclear aromatic hydrocarbons in complex mixtures , Environ. Sci. Technol., 26, 983-990 (1992). 

Liquid-liquid extraction and sorbent accumulation are the most commonly employed isolation-concentration methodologies. In their ideal forms, these methods readily extract or accumulate relatively hydrophobic compounds such as polynuclear aromatic hydrocarbons (PAHs) or polychlorinated biphenyls. However, when HPLC is likely to be the method of choice, the compounds are likely to be highly polar or ionic. In these common cases, adaptation of the traditional methodology can readily serve to carry out the necessary isolation. 

Macroreticular resins, particularly the Amberlite XAD series, have been used extensively to isolate and concentrate trace organic compounds from drinking water (1-8). We have previously reported the use of an XAD cartridge for this purpose and have evaluated the system for the analysis of organophosphorus pesticides (OPs) (4), polynuclear aromatic hydrocarbons (PAHs) (5), phosphate triesters (TAAPs) (6), or-... 

Similarly, many xenobiotics, such as pesticides, polynuclear aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs), plasticizers, phenols, and some other dmg residues, are also toxic even at trace levels present in the earth s ecosystem [5-7], Without analytical techniques capable of detecting them at nanolevels, we assume the absence of these pollutants in the environment, while these notorious pollutants accumulate in our body tissues resulting in various diseases and side effects such as carcinogenesis and failure of many vital body organs including the kidney, liver, and heart [8-11]. Under such situations, it is essential to have analytical techniques that can detect dmgs, pharmaceuticals, and xenobiotics in biological and environmental samples at very low concentrations. 

Eiceman GA, Clement RE, Karasek FW. 1981. Variations in concentrations of organic compounds including PCDDs and polynuclear aromatic hydrocarbons in fly ash from a municipal incinerator. Anal Chem 53 955-959. 

Kasiske et al. [219] have described a high performance liquid chromatographic method for six polynuclear aromatic hydrocarbons in trade effluents whose concentration in potable water is regulated by European Community standards, viz. fluoranthene, benzo(e)acetphen-anthracene benzo(k)fluoranthene, benzo(def)chrysene,... 

Saxena et al. [512] used polyurethane foams to concentrate trace quantities of six representatives of polynuclear aromatic hydrocarbons (fluoranthene, benzo(k)fluoranthene, benzo(j)fluoranthene, benzo(a) pyrene, benzo(ghi) perylene, and indeno(l,2,3-cd)pyrene) prior to regular screening of these compounds in US raw and potable waters. Final purification and resolution of samples was by gas chromatography and two-dimensional thin layer chromatography, followed by fluorometric analysis and quantification. 

It is now well established that a variety of organic molecules such as polynuclear aromatic hydrocarbons with low ionization energies act as electron donors with the formation of radical cations when adsorbed on oxide surfaces. Conversely, electron-acceptor molecules with high electron affinity interact with donor sites on oxide surfaces and are converted to anion radicals. These surface species can either be detected by their electronic spectra (90-93, 308-310) or by ESR. The ESR results have recently been reviewed by Flockhart (311). Radical cation-producing substances have only scarcely been applied as poisons in catalytic reactions. Conclusions on the nature of catalytically active sites have preferentially been drawn by qualitative comparison of the surface spin concentration and the catalytic activity as a function of, for example, the pretreatment temperature of the catalyst. Only phenothiazine has been used as a specific poison for the butene-1 isomerization on alumina [Ghorbel et al. (312)). Tetra-cyaonoethylene, on the contrary, has found wide application as a poison during catalytic reactions for the detection of active sites with basic or electron-donor character. This is probably due to the lack of other suitable acidic probe or poison molecules. 

Composition of Parent Pitch. Once the chemical composition of the carbonizing system moves away from the comparative simplicity of polynuclear aromatic hydrocarbons to that of industrial pitches, then the pyrolysis chemistry incorporates effects caused by the presence of heteroatoms (0, N and S) and alkyl and naphthenic groups. In general terms, the system becomes more Reactive creating higher concentrations of radicals detectable by ESR. This in turn, leads to enhanced cross-linkages and polymerization of molecular constituents of any mesophase which is formed, and this causes enhanced viscosity and a reduction in size of optical texture. 

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