ANALYTICAL-CHEMISTRY OF 4 NITRODIBENZOPYRANONE ISOMERS FOR AMBIENT AIR ANALYSIS

Nitrodibenzopyranones have recently been shown to be present in ambient air and to contribute substantially to the mutagenicity of ambient air particulate extracts. To allow their isomer-specific analysis in ambient samples, nitro-isomers (2-, 3- and 4-nitrodibenzopyranone and a fourth isomer tentatively identified as 8-nitrodibenzopyranone) and the parent dibenzopyranone were characterized by their H-1-NMR spectra, mass spectra and their gas chromatographic retention indices on DB-5, DB- 1701 and SB-smectic stationary phases. 2-, 3 and 4-Nitrodibenzopyranone were well resolved on DB-5 and DB-1701 columns. Since only 2- and 4-nitrodibenzopyranone have been identified in atmospheric samples, 3-nitrodibenzopyranone may prove suitable as an internal standard for quantitative analysis.