Highly selective and sensitive detection of mercury (II) and dopamine based on the efficient electrochemiluminescence of Ru(bpy)32+ with acridine orange as a coreactant

Abstract Developing highly specific, rapid, and cost-effective electrochemiluminescence (ECL) methods capable of detecting multiple analytes remains a compelling research goal but it is still a substantial challenge due to narrow choice of ECL systems. In this study, efficient ECL detections were achieved by using anodic Ru(bpy)32+-acridine orange (AO) ECL system. In present system, dimethylamino substituent on acridine ring acts as active sites for strong ECL generation, while heterocyclic nitrogen atom (–N–) contributes to specific complex formation with metal ion. Accordingly, this anodic ECL method was exploited for highly sensitive detection of both mercury (II) (Hg2+) and dopamine (DA), with detection limits as low as 0.36 nM (linear range 0.01–50 μM) and 1.0 nM (linear range 0.01–10 μM), respectively. The detection mechanism of Hg2+ detection was supported by density functional theory (DFT) calculations. Notably, the ECL method exhibit superior selectivity over numerous competing interfering agents. Moreover, the method achieved the detection of both targets in practical media with excellent recoveries (96.0-103.8%). Importantly, the method demonstrates potential advantages in terms of selectivity, sensitivity, rapidity, simplicity, and low cost. This work realizes a successful attempt to further expand the analytical applications of ECL systems and may initiate new thoughts in utilizing acridines in diverse ECL-based sensing and imaging applications.