I. Voltammetric Evaluation of the Effective Acidities (pKa') for Protic Substrates in Aprotic Solvents. II. Effects of Media and Electrode Materials on the Electrochemical Oxidation of Molecular Hydrogen ; Quantitative Determination of Dissolved H2. III. Potentiometric Titrations and Oxidation-reduction Potentials of Several Iron Superoxide Dismutases