A methodology based on 77 K laser-excited fluorescence spectroscopy, fluorescence quenching, and fluorescence line narrowing is shown to be a highly selective and sensitive approach for the study of polycyclic aromatic carcinogen-DNA complexes. Three and five different DNA adducts derived from (+)-trans-7,8-dihydroxy-anti-9,10-epoxy-7,8,9,10-tetrahydrobenzo [a]pyrene and its (-)-enantiomer are identified, respectively. Two different methods are used to classify the adducts as type I (interior) or type II (exterior), and both yield consistent results. The first high-resolution fluorescence excitation spectra are reported for DNA adducts. These spectra are suggested to be useful for characterizing the strength of the interaction between the fluorescent chromophores and the DNA bases. The above methodology has the potential for monitoring the fates of different adducts as a function of time in repair-competent cells.

In order to gain insight as to the structure(s) of the adduct formed in vivo between human hemoglobin and the anti-diol epoxide (anti-BPDE) of benzo[a]pyrene (BaP), a series of model compounds was synthesized to investigate the effect on the fluorescence line-narrowing (FLN) spectra of heteroatom substitution at C-10 in BaP tetrahydrotetrol analogues. Spectra taken at 4.2 K by vibronic laser excitation at both 356.9 and 363.4 nm revealed marked differences between BaP tetrahydrotetrols and synthetic thioether, amino, and ester adducts of anti-BPDE. Use of these same excitation wavelengths on intact human globin samples obtained from individuals environmentally exposed to ambient levels of BaP yielded vibronic FLN spectra that were virtually indistinguishable from those of a synthetic C-10 carboxylic ester derived from anti-BPDE.