Polycyclic aromatic hydrocarbons without

He WC, He WJ (1985) A Novel Nomenclature of Polycyclic Aromatic Hydrocarbons Without Using Graph Centre. Theor Chim Acta 68 301... 

Bioventing technology was developed by the U.S. EPA Risk Reduction Engineering Laboratory to treat soil contaminated by numerous industrial wastes, which is subjected to aerobic microbial degradation, especially to promote the degradation of polycyclic aromatic hydrocarbons.65 It uses a series of air injection probes, each of which is attached to a low-pressure air pump. The air pump operates at extremely low pressures to allow the inflow of oxygen without volatilization of contaminants. Additional additives such as ozone or nutrients may also be supplied to stimulate microbial growth.77... 

Gschwend and Hites (1981) observed that the two closely related polycyclic aromatic hydrocarbons, phenanthrene and anthracene, occur in a ratio of about 3-to-l in urban air. In contrast, sedimentary deposits obtained from remote locations (e.g., Adirondack mountain ponds) exhibited phenanthrene-to-anthracene ratios of 15-to-l. You hypothesize that these chemicals are co-carried in aerosol droplets from Midwestern U.S. urban environments via easterly winds to remote locations (like the Adirondacks) where the aerosol particles fall out of the atmosphere and rapidly accumulate in the ponds sediment beds without any further compositional change (i.e., the phenanthrene-to-anthracene ratio stops changing after the aerosols leave the air). If summertime direct photolysis was responsible for the change in phenanthrene-to-anthracene ratio, estimate how long the aerosols would have to have been in the air. Comment on the assumptions that you make. What are your conclusions ... 

Hawthorne et al. [61] coupled subcritical water extraction of polycyclic aromatic hydrocarbons with extraction using styrene-divinyl benzene extraction discs. The discs can be stored in autosampler vials without loss of polycyclic aromatic hydrocarbons. 

Dale et al. [84] has described a method for the determination of polycyclic aromatic hydrocarbons in contaminated soils which involves use of a laser desorption, laser photoionisation time-of-flight mass spectrometer. This method can be applied directly to soils without extraction and cleaning procedures, and consequently it has great potential as an on-site screening tool. 

Fig. 6.3. Effect of sodium dodecylsulfate in the mobile phase upon electrochromatography of polycyclic aromatic hydrocarbons on a C18-derivatized continuous bed containing sulfonic acid groups (Reprinted with permission from [30]. Copyright 1996 American Chemical Society). Capillary 14 cm (10 cm effective length) x 100 pm i.d. Applied voltage 3.0 kV Eluent 60% (v/v) acetonitrile in 4 mmol/1 sodium phosphate (pH 7.4). (a) 1.0 mmol/1 SDS added to the eluent (b) without addition of SDS (control). Peaks naphthalene (1), 2-methylnaphthalene (2), fluorene (3), phenanthrene (4), anthracene (5).

The efficacy of land treatment for spills of oil and oil products is confirmed in carefully controlled experiments in the laboratory and in the field. Thus, the hydrocarbons in gasoline, jet fuel, and heating oil are extensively degraded in soils treated with fertilizer, lime, and simulated tilling. This approach reduces the total hydrocarbons by up to 95%, eliminates polycyclic aromatic hydrocarbons, and results in complete detoxification in a few months. Crude oil, crankcase oil, jet fuel, heating oil, and diesel oil disappear faster than in a soil without these treatments. 

Low-weight organic molecules, such as volatile organic compounds (VOCs) [25], e.g. hydrocarbons without functionalities or anaesthetics, can be used as print molecules for non-covalent MIPs. If the print molecule is a suitable organic solvent, the print molecule itself is the porogen during the polymerisation process. Enhanced imprinting effects are promoted by n-n interactions between aromatic moieties in monomers and analytes, such as polycyclic aromatic hydrocarbons (PAHs) or aromatic VOCs (xylene or toluene, for example). 

MHP is derived in section 5. From the results obtained with this procedure, we develop a set of simple rules that allow predicting a priori without calculations the existence of vibrational modes that break the MPP (section 6). Finally, we show in section 7 how the nuclear displacements that break the MPP can be a useful indicator of local aromaticity in polycyclic aromatic hydrocarbons. 

Immunochemical methods for low molecular weight (<1000 D) environmental compounds, such as pesticides, nitro aromatics, and PAHs (polycyclic aromatic hydrocarbons) have been developed since more than 25 years (e.g. Hammock and Mumma, 1980 Hammock et al., 1990 Dankwardt, 2000). The most common method is the immunoassay, which is either carried out with (heterogeneous) or without (homogenous) separation steps. Heterogeneous formats that use microtitre plates, plastic tubes and/or membranes as solid supports are more commonly used. 

Is it fascinating to know that the polyynes are considered the key precursors in the formation of polycyclic aromatic hydrocarbons and soot in combustion flames and that a similar mechanism of carbon dust formation can be applied (without flames) to explain the formation and the abundance of elemental carbon in our galaxy. Carbon dust represents about 3% of the... 

In 2003, urban air pollution was monitored at 76 stations (44 and 32 operated by the Ministry of Health and the Ministry of the Environment, respectively) located in 27 cities involved in the Monitoring System (SZU, 2004). In 2003, sulphur dioxide (SO2), nitrogen oxides (NO/N02/NOx), particulate matter (TSP and/or suspended PMio fractions), and mass concentrations of selected metals (arsenic, chromium, cadmium, manganese, nickel and lead) in particulate matter samples were monitored in all the cities of the Monitoring System except for Melnik. The SO2 measurements in the Public Health Service network were terminated at all the manual stations in the cities with CHMI stations in the cities without a CHMI station, measurements are made during the heating season only). Concentrations of carbon oxide, ozone, polycyclic aromatic hydrocarbons (PAHs) and volatile organic compounds (VOCs) continue to be monitored selectively in a number of the monitored cities. 

The substances for which this phenomenon has been observed are invariably polycyclic aromatic hydrocarbon structures. No exciplex formation has been reported in the literature to involve drug molecules, but this remains a possibility in concentrated solution or perhaps in solid-state mixtures. The consequences of exciplex formation are a radiative or nonradiative return to the ground state without chemical change, or electron transfer leading to chemical reaction of the drug, the quencher, or both. Many photoaddition processes are postulated to proceed via exciplex formation with the quencher molecule becoming chemically bound. 

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