Silver nanoclusters-catalyzed luminol chemiluminescence for hydrogen peroxide and uric acid detection

In the present study, four kinds of bovine serum albumin (BSA) caped silver nanoclusters (Ag NCs) were prepared using different amount of BSA as template, respectively. The diameters of the four prepared BSA-Ag NCs were all less than 4nm which were obtained using high-resolution transmission electron microscopy (HRTEM). All of the BSA-Ag NCs showed catalytic activity in luminol-H₂O₂ chemiluminescent (CL) reaction. It was interesting that different CL kinetic curves were obtained in different BSA-Ag NCs catalyzed CL reaction. Ag NCs with less template exhibited slow and stable signals. The luminophors for all the cases were still 3-aminophthalate ion in an excited state (3-APA*). Mechanism studies showed that Ag NCs with less template molecules have higher affinity to H₂O₂ and are benefit to the generation of ^•OH and ¹O₂. Then, Ag NCs with 4mg/mL of BSA as template was applied to the detection of H₂O₂. Under the optimum experimental conditions, the linear dynamic range for H₂O₂ detection was from 0.14μM to 100μM with a detection limit of 0.016μM. By combining the urate oxidase-catalyzed oxidation reaction, CL detection of uric acid was realized. The linear range of uric acid detection was 2-100μM with a detection limit of 0.75μM. The relative standard deviation (RSD) of six replicates determination of 10μM uric acid was 5.1%. The proposed method has been applied to the detection of uric acid in diluted serum.