Formation of peroxynitrite induced by spark plasma radiation

The formation of peroxynitrite (ONOO−) in water by the action of plasma UV radiation from spark discharge in air has been studied. Solutions with pH0 3.11–12.86 have been treated. In all cases, the pH has been observed to decrease immediately after the treatment and for the following 14 days. An absorption line characteristic of peroxynitrite (λ = 302 nm) appears in the spectrum by the fourth to fifth day after the treatment and reaches a maximum by the 10th–12th day. The appearance of peroxynitrite a few days after the treatment can be caused by the formation of a substance X during a radiation pulse at a high density of active species, which decomposes according to the scheme X → ONOO− → NO 3 − and has a lifetime of about 10 days. The maximal yield of peroxynitrite is (1.2 ± 0.5) × 10−2 mol/L.