Ru(II)-modified metal organic framework as excellent electrochemiluminescence emitter for ultrasensitive nicotine detection

The sensitive and selective nicotine detection in cigarette is necessary due to the cigarette addiction problem and the neurotoxicity of nicotine on human body. In this study, a novel electrochemiluminescence (ECL) emitter with excellent performance was prepared for nicotine analysis, by combining Zr-based metal organic framework (Zr-MOF) and branched polyethylenimine (BPEI)-coated Ru(dcbpy)32+ through electrostatic interaction. Ru(dcbpy)32+ integrated by Zr-MOF could be catalyzed by the reaction intermediates SO4•-, produced from the co-reactant S2O82-, resulting in a significant increase in ECL response. Interestingly, SO4•- with strong oxidizing ability could preferentially oxidize nicotine, leading to ECL quenching. The constructed ECL sensor based on the Ru-BPEI@Zr-MOF/S2O82- system displayed ultrasensitive determination of nicotine with a lower detection limit of 1.9 × 10-12 M (S/N = 3), which is three orders lower than previously reported ECL results and 4-5 orders lower than that of other types of method. This method puts forward a new approach for building efficient ECL system with greatly improved ECL sensitivity for nicotine detection.