FLUOROPHOTOMETRIC DETERMINATION OF TRACES OF NO-2 ION BY THE CATALYTIC QUENCHING OF FLUORESCENCE OF ACRIDINE ORANGE

In a weak HCl solution of 0.024 mol·L-1,the fluorescence quenching oxidation of acridine orange (AO) by KBrO3 was catalyzed by the presence of traces of NO-2 ion.It was found that the intensity of decrease of fluorescence of AO (ΔF) measured at the wavelengths of (λex) 492 nm and (λem) 538 nm kept a linear relationship with the concentration of NO-2 ion in the range of 2.0×10-6-60×10-6g·L-1 with a detection limit of 1.62×10-6g·L-1.Based on these facts,a new catalytic fluorophotometric method for the determination of traces of NO-2 was proposed and applied to the analysis of water samples.RSD′s found were less than 5%,and recoveries in the range of 96% to 105%.