Determination of Hg2+ in Tap Water Based on the Electrochemiluminescence of Ru(phen)32+ and Thymine at Bare and Graphene Oxide‐Modified Glassy Carbon Electrodes

The electrochemiluminescence (ECL) of the Ru(phen)32+/thymine (T) system at bare and graphene oxide (GO)-modified glassy carbon (GC) electrodes was utilized to determine Hg2+ in tap water. The ECL intensity of Ru(phen)32+ was considerably enhanced by the addition of thymine because of the occurrence of ECL reaction between them. Subsequently, the ECL intensity of Ru(phen)32+/T system rapidly decreased with the addition of Hg2+ because of the formation of a T-Hg2+-T complex. A linear response (R2=0.9914) was obtained over a Hg2+ concentration range of 1.0×10−9 mol/L to 1.0×10−5 mol/L with a detection limit of 3.4×10−10 mol/L at a bare GC electrode in 0.1 mol/L phosphate buffer (pH=8.0). The detection limit can be further reduced to 4.2×10−12 mol/L after modification of the GC electrode by GO. To verify its applicability, the proposed method was utilized to determine Hg2+ in tap water and simulated wastewater. The method exhibited good reproducibility and stability and thus reveals the possibility of developing a novel ECL detection method for Hg2+.