A chemiluminescence biosensor based on the peroxidase-like property of molybdenum disulfide/zirconium metal-organic framework nanocomposite for diazinon monitoring

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/zirco-nium 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) nano -composite 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 stability.