Electrochemiluminescence properties of Tb(III) nicotinic acid complex and its analytical application

A water soluble lanthanide Tb(III) complex Tb2(C6NO2H4)6(H2O)4 has been synthesized as luminescent material, and it is characterized by X-ray crystallography, infrared spectra and elemental analysis, respectively. This material showed excellent characterize of electrochemiluminescence (ECL) in the presence of co-reactant potassium peroxodisulfate (K2S2O8) at glassy carbon electrode. With the increase of the concentration for nicotinic acid (NA), the ECL intensity of the complex/K2S2O8 system in HAc-NaAc buffer solution will be decreased apparently. Novel approach for the detection of nicotinic acid (NA) was developed based on the quenching effect of NA. Furthermore, the possible mechanisms for the ECL behavior of Tb2(C6NO2H4)6(H2O)4/K2S2O8 system are proposed. The effects of K2S2O8 concentration, pH of the buffer on the ECL intensity have also been discussed in detail. The experiment results showed that the limit of detection for NA was 6.0×10−7 M (S/N=3) with a linear range of 2.0×10−6-2.0×10−4 M.