An Amperometric Flow Injection Analysis of Dissolved Hydrogen Molecule Using Tightly Immobilized Electrodeposited...

An amperometric sensor based on flow injection analysis (FIA) of dissolved hydrogen molecules was first developed using electrodeposited platinum particles on glassy carbon electrodes modified with nitrogen-containing functional groups (Pt-NGC) as the working electrode. A glassy carbon (GC) electrode was covalently modified by electrochemical oxidation/reduction procedures. The redox waves between hydrogen ions and hydrogen molecules at highly positive potential range in the hydrodynamic voltammogram were obtained by using a Pt-NGC electrode. The specific electrocatalytic activity for the electrode oxidation of hydrogen molecules has successfully been applied to the FIA of dissolved hydrogen. The typical current vs. time curve was obtained by the repetitive measurement of dissolved hydrogen, and the measurement of dissolved hydrogen was fully completed in a short time (∼15 s). A linear relationship was obtained between the oxidation current of hydrogen molecules and dissolved hydrogen concentration. This indicates that our proposed technique can be used for the determination of the dissolved hydrogen concentration. The fabrication method of the present sensor is very simple because the direct modification of the glassy carbon electrode surface can be performed, differing from the tedious fabrication method in which electrocatalytic carbon powder prepared must be immobilized to the surface of the glassy carbon electrode using Nafion coating and high temperature treatment.