Electrochemiluminescent assay based on Co-MOF and TiO₂ for determination of bisphenol A

An electrochemiluminescence (ECL) sensor for determining bisphenol A (BPA) was prepared based on titanium dioxide (TiO₂) and Co-MOF. TiO₂ is a co-reaction promoter that amplifies the ECL signal in the Ru(bpy)₃²⁺-trinpropylamine (TPrA) system. When the electrode is modified with Co-MOF the ECL signal is significantly enhanced. This is because Co-MOF can not only be used as a co-reaction accelerator but also as a carrier to adsorb more luminescent substances. Possible mechanisms for amplifying the original signal through the synergistic action of the two substances are investigated. The ECL strength decreases with increasing concentrations of BPA, and the amount of BPA can be determined by the change in ECL signal strength (ΔI). Under optimal experimental conditions, the linear range of BPA was 2.0 × 10^-10 to 2.0 × 10^-5 M, with a determination limit of 6.7 × 10^-11 M (3σ/m). The relative standard deviation (RSD) of the signal for ten consecutive measurements was 1.5%. The sensor can be used to detect BPA in bottled samples with recoveries of 96 to 105%.