SPECTROSCOPIC INVESTIGATION OF FLUORESCENCE QUENCHING AGENTS .4. SELECTIVITY OF NITROMETHANE FOR DISCRIMINATING BETWEEN ALTERNANT VERSUS NONALTERNANT POLYCYCLIC AROMATIC-HYDROCARBONS IN SOLVENTS OF DIFFERING POLARITIES

To further assess the applicability of nitromethane as a selective que nching agent for alternant vs. nonalternant polycyclic aromatic hydroc arbons in HPLC analysis, we measured the effect that it has on the flu orescence emission behavior of 96 different polycyclic aromatic hydroc arbons dissolved in a binary ethyl acetate/acetonitrile solvent mixtur e. Nitromethane quenching results are compared with previously reporte d acetonitrile, aqueous/acetonitrile, and toluene/acetonitrile solvent mixtures. Results of these measurements revealed that the ''selective quenching'' rule is obeyed for the vast majority of PAHs in all solve nts considered thus far, with the coronene derivatives being the only major exceptions.