Comparative studies on the electrogenerated chemiluminescent and amperometric behavior of the Ru(bpy)32+ system on a paraffin-impregnated graphite electrode and a glassy carbon electrode

The electrogenerated chemiluminescent (ECL) and amperometric behavior of Ru(bpy)32+ system on a paraffin-impregnated graphite electrode (PIGE) and a glassy carbon electrode (GCE) was studied by different electrochemical techniques. Under conventional cyclic voltammetric (CV) conditions, two anodic ECL peaks (EP1 and EP2) (vs. SCE) were observed at 1.18 and 1.37 V for a PIGE, and at 1.20 and 1.44 V for a GCE. The EP1 normally occurred, but not the EP2. A complicated mechanism was involved in the formulation of EP2. A detection limit as low as 1×10−9 mol l−1 of C2O42− was obtained on the PIGE by the CV method at 100 mV s−1. Strong ECL signals were found on both electrodes in either an oxalate-containing aqueous solution or an organic solution when a cyclic square wave (CSW), between two suitable potentials was used. However, the GCE showed higher reproducibility than the PIGE for continuous CSW (n=10) measurements. Chronoamperometry was also applied by using a potential step from 0.15 to 1.85 V. It took 389 ms on a PIGE and 837 ms on a GCE to reach each maximal ECL intensity.