Utilizing the chemiluminescence of 2-substituted-4,5-di(2-furyl)-1H-imidazole–H2O2–Cu2+ system for the determination of Cu2+

In the paper, 2,4,5-tri(2-furyl)-1H-imidazole (TFI) and 2-phenyl-4,5-di(2-furyl)-1H-imidazole (PDFI), were chosen to investigate chemiluminescence (CL) properties of 2-substituted-4,5-di(2-furyl)-1H-imidazoles. The directly oxidized CL of analytes by H2O2 was in detail studied. The H2O2 could directly oxidize TFI/PDFI to produce strong CL emission in basic solution. The addition of Cu2+ into the system could induce significant enhancement of CL signal. Based on this study, it was found that the TFI/PDFI–H2O2–Cu2+ CL system could be successfully applied to the determination of Cu2+. The proposed method has been used to determine trace amount of Cu2+ with a limit of detection (3σ) of 6.5 × 10−11 mol/L, which enables minimal amount of sample for analysis. A satisfactory result has been obtained for the determination of Cu2+ in the reference material samples. The possible oxidized CL mechanism was also discussed briefly based on the photoluminescence (PL) and CL spectra.