One-step synthesis of L-tryptophan-stabilized dual-emission fluorescent gold nanoclusters and its application for Fe3+ sensing

A novel dual-emission fluorescent gold nanoclusters (GNCs) was first synthesized through a one-step method. In the method, the L-tryptophan acted as both the reducing and protecting agents at the same time. The dual-emission bands of the GNCs were found around 360 nm and 450 nm, respectively. The fabricated GNCs were selectively quenched by Fe3+ ion in the presence of EDTA. The GNCs were successfully used as a ratiometric sensor to detect Fe3+ with a linear range from 1 to 500 μM (R2 = 0.9970) and a detection limit as low as 0.16 μM. The relative standard deviation (RSD) at 1 μM for Fe3+ of six repetitive measurements was 0.12%. The practicability of the GNCs was validated by the analysis of serum samples and more than 94% recoveries were obtained. The results indicated that the GNCs possess great potential value for application in biological analysis.