Determination of Hg 2+ in Tap Water Based on the Electrochemiluminescence of Ru(phen) 3 2+ and Thymine at Bare and Graphene Oxide‐Modified Glassy Carbon Electrodes

The electrochemiluminescence (ECL) of the Ru(phen) 3 2+ /thymine (T) system at bare and graphene oxide (GO)‐modified glassy carbon (GC) electrodes was utilized to determine Hg 2+ in tap water. The ECL intensity of Ru(phen) 3 2+ was considerably enhanced by the addition of thymine because of the occurrence of ECL reaction between them. Subsequently, the ECL intensity of Ru(phen) 3 2+ /T system rapidly decreased with the addition of Hg 2+ because of the formation of a T‐Hg 2+ ‐T complex. A linear response ( R 2 =0.9914) was obtained over a Hg 2+ 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 Hg 2+ 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 Hg 2+ .