A 1:l moleratio mixture of anthracene and naphthalene was pyrolyzed in a drop-tube furnace. The product mixture was analyzed by high performance liquid chromatography with diode-array, UV-absorption spectrometric detection (HPLCDAD) and by gas chromatography/mass spectrometry (GCMS). In addition to previously characterized bianthracene and binaphthalene isomers, 6 isomeric naphthyl-anthracenes were identified. Because of the unavailability of standard reference compounds, structural elucidation was achieved by comparing UV spectral features, mass spectral fragmentation patterns, and GCMS and HPLC elution order with those for bianthracenes, binaphthalenes and other structurally similar molecules. In addition, steric hindrance to rotation at the naphthalene-anthracene bond, a factor that governs the degree of non-planarity of the isomers and thus influences HPLC elution order and MS fragmentation patterns, was estimated using a semi-empirical molecular orbital model.
UNDER CONTRACT NO. DE-AC02-76CH00016 WITH THE UNITED STATES DEPARTMENT OF ENERGY. '_' " ....i" :'" _ _2"_ ":'*'-I _,,_TRIEI, UTION OF THIS DOCUMENT tS UNLIMtTr_}_ | Los Angeles urban aerosol and urban sources (e.g. Rogge et al., 1993ab) such that organic aerosol components typical of motor vehicle exhaust and other human activities can be identified, if present, in the Grand Canyon summer atmosphere by reference to the previously measured composition of urban sources. F'.xperimental Methods Ambient Sample Collection" Two monitoring sites were established at different elevations in Grand Canyon National Park: 1) Hopi Point on the south rim of the canyon, and 2) Indian Gardens ., within the canyon itself. As seen in Figure 1, Indian Gardens is located at an elevation of about 3800 ft (118()m) in the Upper Sonoran Zone of the canyon, on the Tonto Plateau, in an area containing scrub brush blending into Pinyon-Juniper woodland above. Hopi Point is on the south rim of the canyon at an elevation of approximately 7000 ft (2174m), in a transition zone between the Upper Sonoran and the Boreal Zones, in an area influenced by Pinyon-Juniper woodland and Ponderosa Pine forests. Indian Gm'dens is Additional support was provided by the U.S. Department of Energy under the Atmospheric Chemistry Program within the Office of Health and Environmental Research under Contract No. DE-AC02-76CH00016.
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