Download or read book Laser Induced Fluorescence Study of the Heterogeneous Interaction of Polycyclic Aromatic Hydrocarbons with Aqueous Surfaces microform Adsorption and Reaction with Gas phase Ozone written by Baagi Thema Mmereki and published by Library and Archives Canada = Bibliothèque et Archives Canada. This book was released on 2005 with total page 328 pages. Available in PDF, EPUB and Kindle. Book excerpt: We have also measured the kinetics and products of a reaction between gas-phase ozone and anthracene adsorbed at the air-aqueous interface. The reactions at the "uncoated" air-water interface and at an interface consisting of a monolayer of various organic compounds were studied. In all the cases, the reaction follows a Langmuir-Hinshelwood mechanism, in which ozone first adsorbs to the air-aqueous interface, and then reacts with adsorbed anthracene. For typical atmospheric ozone concentrations, the estimated reactive uptake coefficient ranges from 2 x 10-8 to 3 x 10-7 depending on the nature of the air-aqueous interface. Smaller (C4, C6) carboxylic acids at the interface inhibit the reaction (compared to the "clean" water surface); 1-octanol enhances it. Under some circumstances, oxidation by ozone on aqueous surfaces may be more important in the atmosphere than gas phase oxidation by OH radicals. The fate of atmospheric semi-volatile organic compounds (SOCs) such as polycyclic aromatic hydrocarbons (PAHs) depends, in part, on their distribution between the gas phase and particulate phases, and oxidation reactions. In the daytime troposphere, photochemically produced OH radicals dominate these reactions, whereas chlorine atoms may contribute to the oxidation of certain PAHs in coastal areas. In the dark, oxidation by nitrate radicals (NO3) may also be important, whereas ozone can contribute to the oxidation both during the day and at night. We have developed a laser-induced fluorescence (LIF) method to study adsorption and oxidation of PAHs at the air-aqueous interface. This method allows to directly probe the mechanisms and extent of PAH uptake on aqueous surfaces. The kinetics of the adsorption of anthracene and pyrene onto "pure" water and water coated with an organic film were measured. The surface uptake coefficients of both PAHs are estimated to be on the order of 10-5, and increase by a factor of 2--3 for uptake to the 1-octanol coated water surface. However, the surface uptake of pyrene to a hexanoic-acid-coated aqueous surface does not display this enhancement. Resolved fluorescence spectra of pyrene adsorbed onto 1-octanol-coated surfaces indicate that pyrene is in a less polar environment than when adsorbed at the hexanoic-acid-coated surfaces.

Download or read book An in Situ Laser induced Fluorescence System for Polycyclic Aromatic Hydrocarbon contaminated Sediments written by Timothy Grundl and published by . This book was released on 2002 with total page 54 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Laser induced Fluorescence of Pyrene and Other Polycylic Aromatic Hydrocarbons PAH in Seawater written by Stephen M. Rudnick and published by . This book was released on 2001 with total page 919 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Laser Induced Fluorescence Studies in the Gas Phase written by Christopher Guy Atkins and published by . This book was released on 1986 with total page 406 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Analytical Laser Induced Fluorescence and Phosphorescence Spectrometry of Aromatic Hydrocarbon Derivatives Prepared in Vapor Deposited Parent Molecule Matrices written by Charles Finley Pace and published by . This book was released on 1986 with total page 516 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Fluorescence Study of Polycyclic Aromatic Hydrocarbons and Their Interactions with Bovine Serum Albumin written by Steven R. Masuda and published by . This book was released on 1981 with total page 194 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book The Development of a Laser induced Fluorescence Method for Rapid Screening of Polyaromatic Hydrocarbons written by Barbara Anne Kirsch and published by . This book was released on 1986 with total page 298 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book An Atomic Force Microscopy and Fluorescence Spectroscopy Study of Two Polycyclic Aromatic Hydrocarbons Adsorbed on Octadecyltrichlorosilane Self assembled Monolayers written by Gillian Louise Grace Goring and published by . This book was released on 1999 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Laser Induced Fluorescence Studies of Water by Electron Impact written by and published by . This book was released on 1998 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Low Temperature Laser induced Fluorescence Studies of Chromophores in Soft Solids and Biological Matter written by Chen Lin and published by . This book was released on 2013 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Low-temperature laser-induced fluorescence spectroscopy has various applications in analytical, physical, and biophysical chemistry. This technique provides information on the fluorescence origin band, zero-phonon lines and phonon-sidebands, inhomogeneous broadening, electron-phonon coupling strength, and ground- and excited-state vibrational frequencies of studied molecules. Examples discussed in this work include studies of DNA/metabolites and monoclonal antibody (mAb)/antigen interactions. The structural basis for the increased reactivity of BPDE towards guanines at 5-methylcytosine ([superscript]M[superscripte]eC):G sites in DNA was investigated by low temperature laser-based spectroscopy, studying the nature of physical complexes of benzo[a]pyrene tetraol in a series of 5-methylcytosine structural DNA analogs. We found that the presence of a C-5 substituent on cytosine and related structural modifications influences the conformation of BPT in DNA analogs, and could explain the increase in guanine reactivity at [superscript]M[superscript]eC:G sites of the p53 tumor suppressor gene that contains endogenenous 5-([superscript]M[superscript]eC. It has been demonstrated that various mAbs can bind a particular cross-reactant by adopting two distinct "red" and "blue" conformations of its binding sites. We showed that the blue conformation of pyrene in several mAbs (including 4D5 mAb) is consistent with [pi]-cation interactions, underscoring the importance of [pi]-cation interaction in ligand binding. We propose that considerable narrowing of the fluorescence origin band of the ligand in the protein environment could be regarded as a simple indicator of [pi]-cation interactions. It is also shown that time-resolved delta fluorescence line-narrowing ([delta]FLN) spectroscopy, using excitation within the (0,0)-transition band, provides more reliable information of the frequency dependence of the electron-phonon coupling (Huang-Rhys factor, (S

Download or read book Laser induced Fluorescence Studies of Complex Molecules written by Kah Hieng Wong and published by . This book was released on 1988 with total page 268 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Sensitized Fluorescence for the Detection of Polycyclic Aromatic Hydrocarbons written by Emmett Matthew Smith and published by . This book was released on 1978 with total page 28 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Absorption and Laser Induced Fluorescence Spectra of Some Aromatic Molecules written by Karim H. Hassan and published by . This book was released on 1990 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book UV Laser Induced Fluorescence Spectroscopic Studies and Trace Detection of Dissolved Plastics bisphenol a and Organic Compounds in Water written by Vasanthi Sivaprakasam and published by . This book was released on 2002 with total page 494 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book The Application of Laser Induced Fluorescence to the Study of Electron Impact Excitation of Atoms and Molecules microform written by Peter W. Zetner and published by National Library of Canada. This book was released on 1985 with total page 462 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Chemical Biomarkers in Aquatic Ecosystems written by Thomas S. Bianchi and published by Princeton University Press. This book was released on 2011-02-28 with total page 417 pages. Available in PDF, EPUB and Kindle. Book excerpt: This textbook provides a unique and thorough look at the application of chemical biomarkers to aquatic ecosystems. Defining a chemical biomarker as a compound that can be linked to particular sources of organic matter identified in the sediment record, the book indicates that the application of these biomarkers for an understanding of aquatic ecosystems consists of a biogeochemical approach that has been quite successful but underused. This book offers a wide-ranging guide to the broad diversity of these chemical biomarkers, is the first to be structured around the compounds themselves, and examines them in a connected and comprehensive way. This timely book is appropriate for advanced undergraduate and graduate students seeking training in this area; researchers in biochemistry, organic geochemistry, and biogeochemistry; researchers working on aspects of organic cycling in aquatic ecosystems; and paleoceanographers, petroleum geologists, and ecologists. Provides a guide to the broad diversity of chemical biomarkers in aquatic environments The first textbook to be structured around the compounds themselves Describes the structure, biochemical synthesis, analysis, and reactivity of each class of biomarkers Offers a selection of relevant applications to aquatic systems, including lakes, rivers, estuaries, oceans, and paleoenvironments Demonstrates the utility of using organic molecules as tracers of processes occurring in aquatic ecosystems, both modern and ancient

Download or read book Fluorescence of Aromatic Hydrocarbons in Aqueous Solution written by Roxane Meidinger and published by . This book was released on 1993 with total page 10 pages. Available in PDF, EPUB and Kindle. Book excerpt: The fluorescence properties of more than 20 aromatic hydrocarbons in aqueous solution have been characterized. The list includes benzene, toluene, ethylbenzene, and xylenes (BTEX) and naphthalene and its 1- and 2-methyl derivatives. They are found in most fuels and are sufficiently soluble to pose an environmental hazard. The fluorescence of aromatic hydrocarbons is well known, but the work reported here represents the first comprehensive characterization for the aqueous phase. BTEX fluorescence quantum yields are lower in aqueous solution than in organic solvents; a similar, but less pronounced, trend holds for the naphthalenes. Fluorescence lifetimes were determined in a fiber optic light delivery and collection mode similar to that which would be used in field measurements. Stern-Volmer analysis stows that fluorescence quenching by dissolved oxygen and anions at levels expected for environmental samples is small. Interering fluorescence of humic substances is a greater concern.