Fluorescence enhancement of bovine serum albumin gold nanoclusters from La3+ ion: Detection of four divalent metal ions (Hg2+, Cu2+, Pb2+ and Cd2+)

The combination of La3+ ion and bovine serum albumin gold nanoclusters (La3+ ion-BSA-AuNCs)-based nanosensor creates a novel and innovative miniaturized analytical method for the detection of four divalent metal ions (Hg2+, Cu2+, Pb2+ and Cd2+) simultaneously. In this work, the fluorescence enhancement was noticed in BSA-AuNCs by the addition of La3+ ion, exhibiting emission peak at 652 nm when excited at 323 nm. The fabricated La3+ ion-BSA-AuNCs acted as a fluorescent sensor for the detection of four divalent metal ions (Hg2+, Cu2+, Pb2+ and Cd2+) via fluorescence quenching (Hg2+, Cu2+ and Pb2+) and fluorescence enhancement (Cd2+) mechanisms. The La3+ ion-BSA-AuNCs-based fluorescent nanosensor exhibited good linearity with limits of detection (LOD) of 0.02, 0.048, 0.19 and 4.93 µM for Hg2+, Cu2+, Pb2+ and Cd2+ ions, respectively. The practical application of La3+ ion-BSA-AuNCs-based fluorescence method was examined for the analysis of four divalent metal ions (Hg2+, Cu2+, Pb2+ and Cd2+) in various environmental water samples. Thus, the developed probe exhibited several merits such as miniaturization, easy of operation, which allow to use as a promising analytical platform for on-site parallel detection of four divalent metal ions in real samples.