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Abstract
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Background: Organophosphorus pesticides are widely used in agriculture owing to their high effectiveness as
insecticides. Among these, diazinon is a common environmental contaminant that acts as an acetylcholinesterase
(AChE) enzyme inhibitor. As the current methods are too expensive and time-consuming for routine analysis of
diazinon, its trace monitoring by rapid and sensitive methods is critical to protect the environment and human
health.
Results: A biosensor was introduced for the indirect detection of diazinon using a molybdenum disulfide/zirconium
metal-organic framework (MoS2@MIP-202(Zr)) nanocomposite. The probe is based on the peroxidase
mimic of the prepared nanocomposite on NaHCO3–H2O2 chemiluminescence system as well as the inhibitory
effect of diazinon on the enzymatic activity of AChE. The chemiluminescence signal is gradually decreased with
an increase in diazinon concentration, and there is a linear relationship between the analytical signal and
diazinon concentration. Under the optimum conditions, the calibration plot is linear in the concentration range
of 0.5–300.0 nmol L 1. The limit of detection and quantification limit of the method are 0.12 and 0.40 nmol L 1,
respectively. The inter-day and intra-day relative standard deviations (% RSD n = 5, diazinon concentration; 100
nmol L 1) are 3.66 and 1.35%, respectively. The method was used for diazinon detection in real water samples,
and the high relative recovery values for the spiked samples along with satisfactory results of a certified reference
material analysis confirmed that the method is accurate and free from the matrix effect.
Significance and novelty: A nano-probe based on the peroxidase-like property of MoS2@MIP-202(Zr) nanocomposite
was developed for the first time for indirect detection of residue levels of diazinon in water samples.
The high stability of the nanocomposite makes it a good alternative for natural peroxidase enzymes such as
horseradish peroxidase with low stabilit
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