Fluorescence spectroscopic studies on the identification and quantification of 7H-dibenzo[c,g]carbazole and dibenz[a,j]acridine metabolites.

Fluorescence spectroscopic techniques were developed and employed in the identification and quantitation of the metabolites of the carcinogenic pollutants 7H-dibenzo[c,g]carbazole (DBC) and dibenz[a,j]acridine (DBA) after HPLC separation. Metabolites formed in vitro with 3-methylcholanthrene (3-MC)-induced Sprague-Dawley rat liver microsomal preparations were used as the model for this research. The fluorescence spectra of the three major DBC metabolites matched those of the synthetic standards, 1-OH-, 3-OH- and 5-OH-DBC, respectively. Similarly, the fluorescence spectra of the four major DBA metabolites matched those of the synthetic standards, 1,2-diol-, 3,4-diol-, 5,6-diol- and 5,6-epoxide-DBA, respectively. Synchronous fluorescence spectroscopy (SFS) has been especially helpful for the identification of these metabolites since it produces a single peak for each compound. Regression equations of the SFS peak areas versus concentrations of the synthetic standards were used to calculate quantities of the microsomal metabolites from the SFS peak areas of the metabolites. These values were comparable with those quantities calculated from radioactivity measurements. The use of HPLC combined with SFS is a convenient and sensitive non-radiometric method which can be used to identify and quantify DBC and DBA metabolites.