Evaluation of 1,2-diaminoanthraquinone (DAA) as a potential reagent system for detection of NO

The reaction of 1,2-diaminoanthraquinone (DAA) with NO has been investigated for potential development into an optical fibre chemical sensor. In aqueous solutions a linear calibration was obtained between 0 and 40 μM NO with a calculated detection limit of about 5 μM (s/n = 3). DAA was shown to be pH independent between 6 and 10 with a pKa of ∼5.5 making it a suitable reagent for detection of physiological NO. NO was shown to quench the fluorescence of DAA and this was due to a static quenching mechanism. The effects of nitrite, peroxynitrite, superoxide and hydrogen peroxide were investigated. Peroxynitrite did not react with DAA and nitrite did not interfere with the reaction of NO with DAA. Though attempts to immobilize DAA in silicone rubber and nafion were successful, exposure to NO gas did not result in a significant response. © Springer-Verlag 2005.