A table is given of the compounds of low volatility, whose experimental solubilities in supercritical carbon dioxide have been published up to the end of 1989, with the temperature and pressure ranges of the experimental measurements, the experimental method, and references to the source of data. The data for pure compounds, which were presented in tabular form in the original publications, are shown in a series of figures along with correlation lines for each isotherm. The method of correlation was to fit the experimental data for each isotherm, in the form of the natural logarithm of the product of mole fraction and pressure, to a linear function of density above a pressure of 100 bars. The constants obtained from the fitting procedures are given in a table. Procedures for estimating, from these constants, the solubilities of the compounds at temperatures and pressures different from those of the experimental data are suggested.

Volatile organic compounds play a central role in the processes that generate both urban photochemical smog and tropospheric ozone. For successful and accurate prediction of these pollution episodes, identification of the dominant reactive species within the volatile organic carbon pool is needed. At present, lack of resolution inherent in single-column chromatographic analysis limits such a detailed chemical characterization of the complex urban atmosphere. Here we present an improved method of peak deconvolution from double-column (orthogonal) gas chromatography. This has enabled us to isolate and classify more than 500 chemical species of volatile organic compounds in urban air, including over 100 multi-substituted monoaromatic and volatile oxygenated hydrocarbons. We suggest that previous assessments of reactive carbon species may therefore have underestimated the contribution made by volatile organic compounds to urban pollution, particularly for compounds with more than six carbon atoms. Incorporating these species in predictive models should greatly improve our understanding of photochemical ozone yields and the formation of harmful secondary organic aerosols.

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3897 3.4. High Mass Limits to UV-Fluorescence 3899 4. Examining High Mass Fractions by Size Exclusion Chromatography (SEC) 3900 4.1. Limitations of Using Tetrahydrofuran As Eluent in SEC 3901 4.2. Limitations of Using NMP as Eluent in SEC 3902 4.3. How To Explain the "Excluded Peak"? 3902 4.4. The Use of NMP−Chloroform Mixtures As Eluent 3903 5. Examining High Mass Fractions by Mass Spectrometry 3904 5.1. Gas-Chromatography − Mass Spectrometry 3904 5.2. Pyrolysis-GC-Mass Spectrometry (Py-GC-MS) 3904 5.3. Heated Probe-Mass Spectrometry 3906 5.4. Field Ionization Mass Spectrometry 3906 5.5. Laser Induced Acoustic Desorption (LIAD) 3907 5.6. Complex, Polydisperse Samples by FT-ICR-MS and Different Ionization Methods 3907 5.6.1. Electrospray Ionization Mass Spectrometry (ESIMS) 3907 5.6.2. Field Desorption and Atmospheric Pressure Photoionization Methods 3908 5.7. Analysis of Complex, Polydisperse Samples by Laser Desorption/Ionization Mass Spectrometry (LDTOFMS) 3908 5.8. Upper Mass Detection Limits of LD-MS Systems 3909 6. Examining Higher Mass Fractions by Solution State 13 C NMR 3910 7. Comparing Calculated Parameters from Three Distinct Samples 3912 7.1. Coal Tar Pitch Fractions 3912 7.2. Fractions of Maya (Mexican) Heavy Crude 3913 7.3. Examining Fractions of Synthetic Crude Prepared from the Athabasca Tar Sands 3914 7.4. Common Features of Results from the Three Sets of Samples 3917 8. Summary and Conclusions 3918 8.1. Aims of the Review 3918 8.2. The Need for Fractionation 3919 8.3. Limitations of Individual Analytical Techniques 3919 8.4. Several Novel Approaches of the Work 3919 8.5. Closing Emphatic Remarks 3919 Author Information 3920 Corresponding Author 3920 Present Address 3920 Notes 3920 Biographies 3920 Acronyms 3921 References 3921

Carbonaceous soot has been generated from pine in a range of appliances to simulate different combustion conditions. The fuel as well as biomass cell wall components have been studied by pyrolysis-GC-MS and pyrolysis-GC-TCD. In addition, the soots have been probed using both pyrolysis-GC-MS and direct inlet mass spectrometry (DI-MS). The material collected from the pine combustion is smoke, and the major component is a carbonaceous soot. The soots contain both organic carbon (adsorbed species) and black (solid) soot, and the organic carbon consists of primary pyrolysis products from the cell wall components, as well as decomposition products, PAH and oxidized PAH. The black carbon contains oxygen functionality (of the order of 5-10 wt % O), and there are indications that this is incorporated during soot growth, although surface oxidation on reactive sites could also be important. The decomposition products suggest an important additional PAH route is via cyclopentadiene, which is derived after cracking of lignin monomer fragments. Kinetic modeling also highlights the lignin monomers as important contributions to the soot production pathways. A model is proposed which, in addition to the hydrogen abstraction carbon addition (HACA) mechanism, incorporates the cyclopentadiene and the O-PAH addition routes to soot.