The decay of ONOOH near neutral pH has been examined as a function of isomerization to H+ and NO3−, and decomposition to NO2− and O2via O2NOO−. We find that in phosphate buffer kisomerization = 1.11 ± 0.01 s−1 and kdisproportionation = (1.3 ± 0.1) × 103 M−1 s−1 at 25 °C and I = 0.2 M. In the presence of 0.1 M tris(hydroxymethyl)aminomethane (Tris), the decay proceeds more rapidly: kdisproportionation = 9 × 103 M−1 s−1. The measured first half-life of the absorbance of peroxynitrite correlates with [Tris]0·([ONOO−]0 + [ONOOH]0)2, where the subscript 0 indicates initial concentrations; if this function exceeds 6.3 × 10−12 M3, then Tris significantly accelerates the decomposition of peroxynitrite.
我们研究了在接近中性pH值时ONOOH的衰减,衰减与异构化为H+和
NO3−以及通过O2NOO−分解为
NO2−和O2有关。我们发现,在25°C和I = 0.2 M时,
磷酸盐缓冲液中的异构化速率=1.11±0.01 s−1,歧化速率=(1.3±0.1)×103 M−1 s−1。在0.1 M三(羟甲基)
氨基
甲烷(
Tris)存在下,衰减速度更快:歧化速率=9×103 M−1 s−1。过氧化
亚硝酸盐吸收度的测量半衰期与[
Tris]0·([ONOO−]0 + [ONOOH]0)2相关,其中下标0表示初始浓度;如果该函数超过6.3