Spectrofluorometric analysis of aromatic compounds: Review of applicability of nitromethane as a selective fluorescence quenching agent for identification of alternant vs. nonalternant polycyclic aromatic hydrocarbons

Applicability of nitromethane as a selective fluorescence quenching agent for discriminating between alternant versus nonalternant polycyclic aromatic compounds is critically reviewed. Experimental data for 170 different polycyclic aromatic hydrocarbons (PAHs) and polycyclic aromatic nitrogen hetero-atoms (PANHs) dissolved in nonelectrolyte solvents and in aqueous micellar solvent media are presented. Specific items examined include the basic quenching mechanism and determination of rate constants, chemical and instrumental artifacts associated with accurate determination of fluorescence emission intensities, and the effect that solvent polarity, surfactant headgroup charge and electron donating and electron withdrawing substituents have in regards to fluorescence emission quenching by nitromethane.