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of polycyclic aromatic hydrocarbons and heavy metals in bread . J. Hazard. Mater. , 80 , 1 – 8 . Akpambang , V.O.E. , Purcaro , G. , Lajide

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Polycyclic Aromatic Hydrocarbons (PAHs) in Ambient Air Using Gas Chromatography/mass Spectrometry (GC/MS). Compendium of Methods for the Determination of Toxic Organic Compounds in Ambient Air. EPA/625/R-96/010b. Washington, DC: U.S. EPA, Center for

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Introduction Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous pollutants in the atmosphere, soil, water, and food. PAHs are known for their potential teratogenicity, carcinogenic, and mutagenic properties. Due to their

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Introduction The group of polycyclic aromatic hydrocarbons (PAHs) is largely distributed in the nature [ 1 ]. They contain two or more fused aromatic rings. They are formed as a result of many natural and anthropogenic processes. The two main

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Coover, M. P. and Sims, R. C. (1987): The effect of temperature on polycyclic aromatic hydrocarbon persistence in an unacclimated agricultural soil. Haz. Waste Haz. Mat. 4, 69–82. Sims R. C

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Introduction The category of polycyclic aromatic hydrocarbons (PAHs) contains diverse compounds, which consist of three or more fused aromatic rings. They are ubiquitously present in the environment as natural

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Abstract  

Nano Ni–W catalysts with different tungsten contents prepared by mixing alkaline nickel carbonate with ammonium tungstate show high activity and good sulfur tolerance for hydrogenation of thiophene-containing ethylbenzene. The catalysts were characterized by XRD, TPR, SEM, Raman and BET. The results show that the activity of the catalysts for ethylbenzene hydrogenation is affected profoundly by W loading and the best result was obtained on catalyst with W/Ni ratio equal to 0.16. The increase of activity of the catalyst can be attributed to the interaction between Ni and W doped and the increase of the surface area of the catalyst.

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Abstract  

In this study, the use of differential scanning calorimetry (DSC) is demonstrated as a powerful technique that can provide accurate thermodynamic property values of environmental contaminants such as polycyclic aromatic hydrocarbons (PAHs). In total, 47 high purity PAH certified reference materials were selected and analysed by DSC. Their onset melting temperature, enthalpy of fusion and eutectic purity were calculated from the obtained melting endotherms. In addition, the entropy of fusion, which was calculated from the onset melting temperature and enthalpy of fusion, is presented. All measurements were evaluated in a metrologically rigorous manner, including measurement uncertainties.

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Summary  

The degradation of a mixture of 18 different polycyclic aromatic hydrocarbons (PAHs) has been studied in acetonitrile solution by usingg-radiation at radiation doses of 100, 200 and 300 kGy. The mixture of radiolyzed PAHs was analyzed by liquid chromatography (HPLC) using a diode array detector. Radiolysis at 100 kGy total dose is already sufficient to cause the complete disappearance of all PAHs with the exception of fluorene and crysene which still survive in small amounts. They are known to be among the most radiation-resistant PAHs and can be completely eliminated from the radiolyzed solution by a treatment with ozone. Alternatively higher radiation dose (200 kGy) is needed to eliminate fluorene and crysene completely from the acetonitrile solution. PAHs can be degraded completely with an excess of ozone but the distribution of products is of course different from that obtained by radiolysis and radiolysis followed by ozonolysis.

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Abstract  

The application of differential scanning calorimetry (DSC) for purity determination is well documented in literature and is used amongst others in the analysis of pure organic crystalline compounds. The aim of this work is to examine whether the DSC method for purity determination consistently produces values for the purity of polycyclic aromatic hydrocarbons (PAHs) which are sufficiently accurate as required for the certification of reference materials. For this purpose, 34 different existing PAH certified reference materials were tested. The DSC results are shown to be consistent with the results obtained by other methods assessing the organic impurities content in PAHs, like gas chromatography (GC), high performance liquid chromatography (HPLC) and mass spectrometry. Significant differences between the measured values and the certified purity values were observed only in a limited number of cases.

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