Analysis of azanaphthalenes and their enzyme oxidation products by high-performance liquid chromatography, infrared spectroscopy and mass spectrometry.

Adsorption and reversed-phase high-performance liquid chromatography (HPLC) have been successfully used to separate metabolites from the parent heterocycles (isoquinoline, 3-methylisoquinoline, phthalazine, quinazoline, quinoxaline and cinnoline). Retention data are reported. The metabolites, hydroxyazanaphthalenes, which arise as a result of aldehyde oxidase catalysed oxidation, could be extracted in microgram quantities from incubation mixtures by n-butanol. Complete identification of the oxidation products was achieved by collecting fractions corresponding to each compound from the HPLC eluate and subjecting these to infrared and mass-spectral analysis.