Histidine-Stabilized Copper Nanoclusters as a Fluorescent Probe for Selective and Sensitive Determination of Vitamin B12

Abstract

Herein, we report the highly sensitive and selective determination of vitamin B12 (VB12) using histidine-stabilized copper nanoclusters (His-CuNCs) as a fluorescent probe by the spectrofluorometry method. The as-synthesized His-CuNCs were characterized by UV–Vis absorption, steady-state emission, and high-resolution transmission electron microscopy measurements. His-CuNCs exhibited an emission maximum around 443 nm, when excited at 350 nm. The emission intensity of His-CuNCs was significantly quenched by the addition of VB12, hinting that the synthesized probe can be employed for sensing of VB12. Based on the decrease in emission intensity, the concentration of VB12 was determined and the emission intensity of His-CuNCs can be quenched by VB12 via fluorescence resonance energy-transfer mechanism. His-CuNCs showed high selectivity toward the determination of VB12 in the presence of other potentially interfering vitamins, cations, and anions. In addition, the proposed sensing platform displayed a sensitive response to VB12 in the linear range of 4.00–28.00 × 10−6 mol dm−3 with a limit of detection of 3.30 × 10−9 mol dm−3. The proposed sensing system is simple, low cost, selective, and sensitive for the determination of VB12 in biological samples.