Ligand-regulated Cu-BH enhanced luminol chemiluminescence for sensitive detection of p-phenylenediamine in water samples.

In this study, a ligand regulation strategy was employed to synthesize a copper-based dual-ligand material (Cu-BH) via a one-pot solvothermal route. Compared with single-ligand structures, the dual-ligand strategy significantly promoted the exposure of active sites, while also maintaining structural stability and luminescence performance. Cu-BH exhibited excellent peroxidase-like activity, efficiently catalyzing the decomposition of H2O2 to generate reactive oxygen species (ROS), which subsequently induced a significantly enhanced chemiluminescence (CL) signal from luminol. Based on the effective quenching effect of p-phenylenediamine (PPD) on ROS in this CL system, a sensitive CL detection platform was constructed for the detection of PPD. Under optimal conditions, the method showed a linear detection range of 1-30 μmol·L-1 for PPD, with a limit of detection as low as 0.95 μmol·L-1. Compared with most previously reported techniques, the proposed method offers comparable analytical performance, while offering additional advantages including simple instrumentation and rapid signal readout without prolonged incubation. To enable rapid on-site detection, a smartphone-based portable visual semi-quantitative analysis system was developed and successfully applied to the detection of PPD in river water and tap water samples. This work not only provides an effective CL strategy for PPD sensing but also extends the utility of copper-based nanomaterials in environmental analysis.