Bovine serum albumin-stabilized gold nanoclusters as fluorescent probe for enzyme-free detection of glyphosate

In present study, bovine serum albumin (BAS)-stabilized gold nanoclusters (AuNCs) combined with Cu2+ were used for rapid fluorimetric detection of glyphosate in water samples. The morphology and optical properties of synthesized BSA-AuNCs were characterized by TEM, UV–Vis spectroscopy and fluorescence techniques. Theoretically, Cu2+ would react with the tryptophan of BSA-AuNCs, thereby disrupting the surface structure of BSA-AuNCs and allowing aggregation of dispersed BSA-AuNCs, which showed the function to quenching the red fluorescence of BSA-AuNCs at 680 nm. However, in the presence of glyphosate in the system, there are strong chelation interactions between Cu2+ and glyphosate, so the fluorescence of BSA-AuNCs was restored and the recovered intensity is related to the glyphosate concentration. As a result, a linear graph between the fluorescence intensity with glyphosate concentration in the range of 0.06–12 μg/mL was plotted and used for quantification of glyphosate with a detection limit of 8 ng/mL. Satisfactory recoveries were obtained in the determination of spiked water samples, demonstrating that the prepared BSA-AuNCs can be used as a promising tool in the field of environment monitoring of glyphosate residue.