In this study, a highly sensitive fluorescent probe based on bovine serum protein-protected gold nanoclusters (BSA-AuNCs) was developed for the determination of organophosphorus pesticides (OPs).At first, BSA-AuNCs were prepared using a photo stable fluorescent substrate. Acetylcholinesterase (AChE) catalyzes the hydrolysis of acetylthiocholine iodide (ATCI) to produce thiocholine (TCh), and the sulfhydryl groups (SH-) on TCh form Au-S bonds with BSA-AuNCs; thus, the fluorescence of BSA-AuNCs weakens. On the other hand, OPs can inhibit the activity of AChE, thus preventing the generation of TCh, and the fluorescence recovery of BSA-AuNCs occurs. Under optimized experimental conditions, parathion-methyl (PM) was detected in the concentration range of 0.33-6.67 ng mL À1 with a detection limit of 0.14 ng mL À1 (S/N ¼ 3), which is much lower than the maximum residue limits reported in the European Union pesticides database as well as that defined by the U.S. Department Agriculture.Moreover, the assay demonstrated highly sensitive applications in the quantitative determination of OPs in water and food samples.
The quantitative analysis of glyphosate has significant implications for the evaluation of food quality and environmental safety risks. First, copper nanoparticles (Cu NPs) were synthesized using cetyltrimethylammonium bromide (CTAB) as a stabilizing agent, which resolved the limitation associated with atmospheric oxidation of Cu NPs and provided excellent fluorescence stability. Interestingly, the fluorescence of blue-emitting CTAB-Cu NPs was quenched by pH-responsive p-nitrophenol (p-NP) via Forster resonance energy transfer. Herein, a dual read-out sensor based on CTAB-Cu NPs and p-NP was constructed for glyphosate detection. Specifically, acetic acid (HAc) from acetylcholine (ACh) via hydrolysis catalyzed by acetyl cholinesterase (AChE) reduced the pH of the mixed solution and prevented the loss of protons from p-NP, which allowed the fluorescence emission by CTAB-Cu NPs. The presence of glyphosate inhibited the activity of AChE, and the increased pH resulted in proton loss. The fluorescence intensity of CTAB-Cu NPs was quenched, and the solution color changed from colorless to yellow with a UV absorption peak at 400 nm. The sensor can detect ultra-trace levels of glyphosate residues with a limit of detection of 5.43 ng/L. The obtained biosensor was successfully utilized to monitor the degradation of glyphosate in the roots of cabbage and cultivated soil.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.