A highly selective melamine sensor relying on intensified electrochemiluminescence of the silica nanoparticles doped with [Ru(bpy)3]2+/molecularly imprinted polymer modified electrode

In this work, a novel and highly selective molecularly imprinted sensor for the detection of melamine in milk using electrochemiluminescence (ECL) is reported. The preparation was carried out by modification of a glassy carbon electrode with a composite of silica nanoparticles doped with [Ru(bpy) 3 ] 2+ (RUDS) and molecularly imprinted polymer (MIP). The keys of the sensor were to employ RUDS as an ECL luminophore to prevent [Ru(bpy) 3 ] 2+ leaching from the modified electrode and MIP as a material for selective recognition. Taking advantage of the MIP pre-concentration effect, melamine could be extracted from the solution and detected by the resulting ECL signal enhancement of [Ru(bpy) 3 ] 2+ . Under optimized conditions, the relative ECL signal was proportional to the logarithm of melamine concentration in the range of 1   ×   10 −12 –1   ×   10 −7   mol   L −1 , with a detection limit as low as 5   ×   10 −13   mol   L −1 . Compared with the RUDS/non-imprinted polymer, the RUDS/MIP modified electrode displayed high recognition ability, good reproducibility, and stability. To verify its reliability, the fabricated ECL sensor was used for determining the concentration of melamine in milk.