1,2-Diaminoanthraquinone is a useful reagent for the direct detection of nitric oxide (NO) DAA is non-fluorescent; however, it reacts with NO, in the presence of oxygen, to form DAA triazole, yielding red fluorescence, which is visible with a rhodamine filter (λ ≥ 580 nm).For the direct detection of nitric oxide. 1,2-Diaminoanthraquinone is a useful reagent for the direct detection of nitric oxide (NO) DAA is non-fluorescent; however, it reacts with NO, in the presence of oxygen, to form DAA triazole, yielding red fluorescence, which is visible with a rhodamine filter (λ ≥ 580 nm). For the direct detection of nitric oxide.