Spectroscopic Investigation of Fluorescence Quenching Agents. Part IV: 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 quenching agent for alternant vs. nonalternant polycyclic aromatic hydrocarbons in HPLC analysis, we measured the effect that it has on the fluorescence emission behavior of 96 different polycyclic aromatic hydrocarbons dissolved in a binary ethyl acetate/acetonitrile solvent mixture. Nitromethane quenching results are compared with previously reported 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 solvents considered thus far, with the coronene derivatives being the only major exceptions.