Oxidative Transformation of Controlled Substances by Manganese Dioxide

Figure 2

Effect of solution pH on the oxidation of controlled substances by MnO₂: (a) morphine (with 100 μg/L MnO₂) and (b) codeine (with 8 mg/L MnO₂) (morphine and codeine = 100 μg/L, pH = 7, and ionic strength = 10 mM) (the second-order kinetic model developed by Zhang et al. [11] was fitted to describe the codeine oxidation).

(a)

(b)