Electrochemiluminescence of tris(2,2′-bipyridyl)ruthenium(ii)/pyruvate system in the absence of cerium(iii)

Abstract

It has been reported that electrogenerated chemiluminescence (ECL) of the tris(2,2′-bipyridyl)ruthenium(II) (Ru(bpy)₃²⁺)/pyruvate system cannot be observed unless cerium(III) is employed to oxidize pyruvate since it is difficult to oxidize pyruvate either directly on the electrode or by electrogenerated Ru(bpy)₃³⁺. In this study, we find that ECL of the Ru(bpy)₃²⁺/pyruvate system can be observed in the absence of cerium(III) at gold, platinum, glassy carbon, and carbon paste electrodes by using slow scan rate. The slow scan rate may favor the oxidation of more pyruvate and reduce background signal, and thus leads to generation of ECL of the Ru(bpy)₃²⁺/pyruvate system. This finding provides an alternative approach for the determination of pyruvate. Under the optimum conditions, the plots of the ECL versus the concentration of pyruvate is linear in the range of 5.0 × 10⁻⁶ M∼1.0 × 10⁻⁴ M with the detection limit of 5.0 × 10⁻⁶ M. The relative standard deviation is 5.08% for nine consecutive measurements of 5.0 × 10⁻⁵ M pyruvate.