Lanthanide terbium complex: synthesis, electrochemiluminescence (ECL) performance, and sensing application

In this study, a new lanthanide terbium complex, Tb(pzda)3(NO3)3·nH2O, was synthesized by a hydrothermal method and characterized by Fourier transform infrared spectroscopy (FT-IR) and energy-dispersive X-ray spectroscopy (EDS). It was found that the as-synthesized Tb-complex exhibited good electrochemiluminescence (ECL) behavior in the presence of triethanolamine (TEOA) in a HAc-NaAc buffer solution on a glassy carbon electrode. The possible reaction mechanism has been discussed based on the fluorescence spectra and ECL spectra. For sensing applications, it was found that protocatechuic acid (PCA) had an obvious quenching effect on the ECL signal of the Tb-complex, and this resulted in a decreased ECL signal associated with the concentration of PCA. Therefore, a highly sensitive method for the detection of PCA was established with a linear range of 1.283 × 10−10 M to 3.845 × 10−4 M and a detection limit of 0.085 nM at an S/N ratio of 3. This novel ECL assay strategy with an outstanding ECL efficiency offers great potential for pharmaceutical analyses.