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Anal. Chem. 1980, 52, 1350-1351
the work of the authors was being carried out and to V. Di Palo for the sulfur determination. LITERATURE C I T E D (1) Graham, Donald. J . Phys. Chem. 1957, 61 1310-1313. (2) Healey, F. H.; Yu, Y . F.; Chessick, J. J. J . Phys. Chem. 1955, 59, 399-404. (3) Diehl. E. Diplom-Arbeit, Technische Hochschule, Darmstadt, Germany 1960. (4) Laine, N. R.; Vastola. F. J.; Walker, P. L. "Proceedings of the 5th Conference on Carbon", 1961: Peraamon Press: Oxford, Enahnd, 1963: Vel. 11, p 211. (5) Laine, N. R.; Vastola, F. J.: Walker, P. L. J . Phys. Chem. 1963, 6 7 , 2030-2033.
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(6) Kraus, Gerard. J . Phys. Chem. 1955, 59,343-345. (7) Zettlemoyer, A. C. J . Colloid Interface Sci. 1968. 28, 343-348. (8) Boehm, H. P. "Advances in Catalysis"; Academic Press: New York, 1966; Vol. 16, p 179. (9) Wiegand, William 5. Ind. Eng. Chem. 1937, 29,953-956. (10) Di Corcia, Antonio; Liberti, Arnaldo; Samperi, Roberto. J . Chromatog. 1976, 122,149-153. ( 1 1) Di Corcia, Antonio: Samperi, Roberto; Severini, Ciaudio. J . Chromatog. 1979, 170, 325-327. (12j Beilstein, S. "Handbuch der Organischen Chemie", Vol. VI: SpringerVerlaa: Berlin. 1965: 3rd ed.: D 857. (13) Di Cokia, Antonio: Liberti, Arnaldo; Samperi, Roberto. Anal. Chem. 1973, 45, 1228-1232. (14) Di Corcia, Antonio; Samperi, Roberto. Anal. Chem. 1974, 46, 140-142. (15) Di Corch, Antonio; Samperi, Roberto. Anal. Chem. 1974, 46, 977-979.
RECEIVED for review August 2, 1979. Accepted April 2 , 1980.
CORRESPONDENCE Direct Determination of Polynuclear Aromatic Hydrocarbons in Coal Liquids and Shale Oil by Laser Excited Shpol'skii Spectrometry Sir: Coal liquefaction products (coal liquids) and crude shale oil are known to contain substantial concentrations of potentially carcinogenic and mutagenic polynuclear aromatic hydrocarbons (PAHs). The extremely complex nature of these liquid fuels, which are known to contain hundreds of low and high molecular weight organic compounds, has made i t difficult to directly analyze the liquid fuels for PAH compounds. Presently, the PAHs are usually isolated as a compound class followed by the isolation and characterization of the individual molecules by various chromatographic techniques. The most widely used techniques are high resolution, capillary-column, gas chromatography combined with mass spectroscopic characterization or high performance liquid chromatography with fluorescence detection (1-7). These techniques are often inadequate for resolving the complex mixtures of PAHs present in energy related materials ( I , 2, 5 , 8 ) , and they are not readily adaptable to the direct determination of selected high potency species without resorting to time consuming prior separations. In this short communication we show that tunable, dye laser excitation of Shpol'skii effect spectra provides a potentially useful means of determining PAH compounds directly in coal liquids and shale oil without prior isolation of the PAH fraction by chromatographic or other techniques. Shpol'skii Effect, Sharp-Line Luminescence Spectra. The characteristic sharp-line, low-temperature (
