In this study, we have developed a sensitive approach to measure organophosphorus pesticides (OPs) using graphitic-phase C3N4 nanosheets (g-C3N4) combined with a nanomaterial-based quencher MnO2 nanosheets (MnO2 NS). Because MnO2 NS could quench the fluorescence of g-C3N4 via the inner-filter effect (IFE), the enzymatic hydrolysate (thiocholine, TCh) can efficiently trigger the decomposition of MnO2 nanosheets in the presence of acetylcholinesterase (AChE) and acetylthiocholine, resulting in the fluorescence recovery of g-C3N4. OPs, as inhibitors for AChE activity, can prevent the generation of TCh and decomposition of MnO2 nanosheets, accompanied by fluorescence quenching again. So the AChE-ATCh-MnO2-g-C3N4 system can be utilized to detect OPs quantitatively based on the g-C3N4 fluorescence. Under the optimum conditions, the linear range for the determination of parathion-methyl (PM) and 2,2-dichlorovinyl dimethyl phosphate (DDVP) were found in the range of 0.1-2.1 ng/mL with a limit of detection of 0.069 ng/mL, and 0.5-16 ng/mL with a limit of detection of 0.069 ng/mL, respectively. Finally, this method was exploited for the monitoring of PM in real samples. The advantages of the assay are user-friendly, easy-to-ease, cost-effective compared to sophisticated analytical instruments.

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This is a list of supplementary files associated with this preprint. Click to download.
The detection mechanism for PM by proposed assay
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Posted 18 Feb, 2021
Posted 18 Feb, 2021
In this study, we have developed a sensitive approach to measure organophosphorus pesticides (OPs) using graphitic-phase C3N4 nanosheets (g-C3N4) combined with a nanomaterial-based quencher MnO2 nanosheets (MnO2 NS). Because MnO2 NS could quench the fluorescence of g-C3N4 via the inner-filter effect (IFE), the enzymatic hydrolysate (thiocholine, TCh) can efficiently trigger the decomposition of MnO2 nanosheets in the presence of acetylcholinesterase (AChE) and acetylthiocholine, resulting in the fluorescence recovery of g-C3N4. OPs, as inhibitors for AChE activity, can prevent the generation of TCh and decomposition of MnO2 nanosheets, accompanied by fluorescence quenching again. So the AChE-ATCh-MnO2-g-C3N4 system can be utilized to detect OPs quantitatively based on the g-C3N4 fluorescence. Under the optimum conditions, the linear range for the determination of parathion-methyl (PM) and 2,2-dichlorovinyl dimethyl phosphate (DDVP) were found in the range of 0.1-2.1 ng/mL with a limit of detection of 0.069 ng/mL, and 0.5-16 ng/mL with a limit of detection of 0.069 ng/mL, respectively. Finally, this method was exploited for the monitoring of PM in real samples. The advantages of the assay are user-friendly, easy-to-ease, cost-effective compared to sophisticated analytical instruments.

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5
This is a list of supplementary files associated with this preprint. Click to download.
The detection mechanism for PM by proposed assay
Loading...