Gold nanoclusters fluorescence probe for monitoring chloramphenicol and study of two-dimensional correlation fluorescence spectroscopy

Abstract

Chloramphenicol (CAP) is widely used in veterinary practice, including treatment of aquaculture species and livestock husbandry because of its effective antibiotic active against gram-positive and gram-negative microorganisms. However, research shows that, for human body, it leads to serious adverse reactions and side effects. In order to effectively monitor the occurrence of residues of CAP, herein a simple fluorescence probe of glutathione stabilized gold nanoclusters (GSH-AuNCs) is synthesized and characterized. The sensing platform shows high sensitivity and selectivity toward CAP though a fluorescence quenching response. The newly prepared GSH-AuNCs exhibits a strong red emission band at 615 nm under excitation at 360 nm. Nitro of CAP with the property of strong electron affinity results in the charge transfer from GSH-AuNCs to the analyte, which inhibits radiative relaxations and drops the fluorescence intensity consequently. On the basis of fluorescence response, the linear range and detection limit are 0.1~1.0 µM and 0.023 µM respectively. In addition, two-dimensional fluorescence correlation spectroscopy (2D-FL-DOS) is applied to investigate the detail information about charge transfer process to deeply understand the mechanism of fluorescence response of GSH-AuNCs. The cross-peaks in asynchronous spectrum suggest three factors affect the interaction between GSH-AuNCs and CAP.