Abstract Electrochemical sensors are simple, fast, accurate, and low-cost analytical devices. They are especially important to the field of healthcare since they enable measurement of important indicators of patient health such as electrolytes and glucose in blood. Continued development and improvements in electrochemical sensors can result in more accessible, affordable, and effective diagnoses and treatment strategies. Electrochemical sensors employ electrodes, usually modified with a recognition agent specific for the analyte (the biomolecule of interest). The presence of the analyte at the electrode surface is typically measured through an electrochemical reaction that generates a signal in the form of an electric current or difference in electric potential. As an alternative, electrochemiluminescence, a phenomenon whereby an electrochemical reaction generates a product in an electronically excited state that is capable of emitting light, has great benefits due to its high sensitivity, selectivity, and extremely low background signal. Here we employ a camera equipped with a complementary metal-oxide semiconductor (CMOS) detector that is interfaced with a simple zoom lens to measure ECL generated at low-cost pencil graphite electrodes and small electrode arrays using tris(2,2′- bipyridyl) dichlororuthenium(II) hexahydrate ([Ru(bpy)3]2+) with tri-n-propylamine (TPA) as the coreactant. ECL signals produced at pencil graphite working electrodes were linear with respect to [Ru(bpy)3]2+ concentrations for 45–450μM [Ru(bpy)3]2+. The detection limit was found to be 2µM using the CMOS camera with exposure time set at 10s. This proof-of-concept work suggests the pencil graphite electrode with simple imaging system platform can be applied for ECL-based biosensing strategies.

Electrochemiluminescence (ECL) is a phenomenon whereby electrochemical reactions generate a product that is capable of emitting light. ECL’s high sensitivity, selectivity, extremely low background, and relatively simple instrumentation make it particularly well-suited for chemical sensing and biosensing strategies. Here we report a simple ECL imaging system based on a camera interfaced with a zoom lens to compare pencil graphite electrode (PGE) and screen-printed carbon electrode (SPCE) arrays as ECL platforms. With this system, ECL signals generated from tris(2,2′- bipyridine)ruthenium(II) chloride hexahydrate ([Ru(bpy)3]2+) using co-reactant tri-n-propylamine (TPA) were linear with respect to [Ru(bpy)3]2+ concentrations from 9 to 450 μM. Detection limits for [Ru(bpy)3]2+ were found to be 1.8 μM with PGEs and 0.9 μM with SPCEs. Immobilization of a thin polyvinylpyridine (PVP) film ECL reporter [Ru(bpy)2(PVP)10]2+ on SPCEs was also investigated. Overall, the combination of PGEs or SPCEs with the simple ECL imaging system offers a cost-effective approach to ECL-based sensing and biosensing.