Dual-quenching molecular imprinting polymers electrochemiluminescence sensor for diuron detection: triggered by “blocking effect” and interaction of diuron with Triethylamine

Developing a simple, specific, and sensitive method for the detection of diuron is of utmost importance. Herein, a novel dual-quenching molecular imprinting polymers electrochemiluminescence (MIP-ECL) sensor, which effectively combined the "blocking effect" of MIPs and the competitive reaction between diuron and coreactant, was fabricated for high-performance analysis of diuron. Specifically, gold nanoclusters (AuNCs) were immobilized on the electrode interface to generate a robust ECL signal in the presence of triethylamine (TEA) as coreactant. The MIP was subsequently introduced employing thiophene as functional monomer and diuron as template molecule, with the cavities within the MIP utilized for diuron capture after elution. Upon the recombination of diuron, on the one hand, the electron transfer between the electrochemical oxidation product of AuNCs (AuNCs•+) and reactive radicals of TEA (TEA•) was hindered by diuron. On the other hand, a portion of TEA• was consumed by diuron to generate 3-(hydroxychlorophenyl)-1,1-dimethylurea (HCPDMU), a phenyl hydroxyl compound that could also potentially accept electron from TEA•, leading to a subsequent decline in TEA•. Both the mechanisms in turn weaken the generation of the excited-state AuNCs (AuNCs*) and reduce the ECL intensity, leading to the MIP-ECL sensor demonstrating excellent analytical performance for diuron detection. Innovatively, the interaction between diuron and TEA offered a novel research avenue for detecting diuron using the ECL system with TEA as coreactant.