Ion-exchange chromatographic analysis of peroxynitric acid

•Ion-exchange chromatographic analysis of peroxynitric acid was successfully achieved.•Low pH and low temperature conditions were necessary for the IEC analysis.•Decomposition behavior of peroxynitric acid in the solution had been studied.•The molar extinction coefficients of peroxynitric acid were obtained with precision. Ion-exchange chromatographic analysis of peroxynitric acid (O2NOOH) was performed by combining an acidic eluate with an UV–vis detector and immersing the separation column in an ice-water bath. The decomposition behavior of peroxynitric acid in the solution was also studied using this system. The fraction for the peroxynitric acid peak was collected. Ion-exchange chromatographic analysis of this fraction, after standing at room temperature for 24h, showed that the decomposition products were mainly nitrate ions with a very small amount of nitrous acid. The peroxynitric acid peak area correlated perfectly with the total amount of decomposition products. The ion-exchange chromatographic isolation allowed us to evaluate the molar extinction coefficient of peroxynitric acid precisely in a wider wavelength range than previous reports. The value decreases monotonically from 1729±26M−1cm−1 at 200nm to 12.0±0.5M−1cm−1 at 290nm.