Fig. 4.

Plot of k_obs versus [CH₃CH₂CHO] for reaction with H_peroxo at 4 °C and pH 7.0. 50 μM MMOH_red and 100 μM MMOB were mixed rapidly with excess O₂, the reaction mixture was aged for 2 s, and then buffer containing the appropriate concentration of propionaldehyde was introduced. Data were analyzed as noted in the text and fit to eq 3. Data collected at low [CH₃CH₂CHO] (k_init) is depicted in the inset. Error bars represent one standard deviation at the 95% confidence level.