Saturation Concentration of Dissolved O2 in Highly Acidic Aqueous Solutions of H2SO4

Saturation concentrations of dissolved oxygen in an aqueous-H2SO4 medium at 25 (degree) C were measured in pulse radiolytic competition-kinetics experiments, wherein the H atom (H. radical) was generated in situ by a 50-ns electron pulse, and, subsequently, the propensity of its reactions with O2 and another solute of choice were compared on a microsecond time scale. Such direct chemical estimations reveal that an oxygen concentration of ~1.28 mM at pH 2 steadily decreases to ~310 (mu)M at a H2SO4 concentration of ~14 M, and it now provides a quantitative picture for evaluating oxidative stress in high acidity.