Liu_2022_J.Environ.Sci.Health.B__1

In this study, we have developed a sensitive approach to measure organophosphorus pesticides (OPs) using graphitic-phase C(3)N(4) nanosheets (g-C(3)N(4)) combined with a nanomaterial-based quencher, MnO(2) nanosheets (MnO(2) NS). Since MnO(2) NS can quench the fluorescence of g-C(3)N(4) via the inner-filter effect (IFE), enzymatic hydrolysate (thiocholine, TCh) can efficiently trigger the decomposition of MnO(2) nanosheets in the presence of acetylcholinesterase (AChE) and acetylthiocholine (ATCh), resulting in the fluorescence recovery of g-C(3)N(4). OPs, as inhibitors to AChE activity, can prevent the generation of TCh and decomposition of MnO(2) nanosheets while exhibiting fluorescence quenching. Therefore, the AChE-ATCh-MnO(2)-g-C(3)N(4) system can be utilized to quantitatively detect OPs based on g-C(3)N(4) fluorescence. Under optimal conditions, the linear ranges for the determination of parathion-methyl (PM) and 2,2-dichlorovinyl dimethyl phosphate (DDVP) were found to be 0.1-2.1 ng/mL and 0.5-16 ng/mL, respectively, with limits of detection of 0.069 ng/mL and 0.20 ng/mL, respectively. The advantages of this assay are user-friendliness, ease of use, and cost effectiveness compared to other more sophisticated analytical instruments.