Research On Detection Of Organic Phosphorus Pesticides Through Preparation Of Enzyme-free Sensors By Application Of Dye Modification

In recent years,the extensive use of organic phosphorus pesticides has caused serious environmental pollution and pesticide residue above the sanitation standard of agricultural products,giving rise to many food safety incidents.It also leads to the trade and technological barriers set by developed countries with pesticide residues as the main content, making the export of agricultural products of our country subject to serious loss. The hazards of organic phosphorus pesticides have earned widespread international respect. Our country has also taken corresponding measures in the fight against pesticide pollution and pesticide detection. Organophosphate pesticides such as moncrotophos and parathion has become a key testing object during the agricultural product processing, distribution and trading because of its potency and long half-life of degradation.Current detection methods of organic phosphorus pesticide include spectrometry, test paper, chromatography and immunoassay, etc. These methods are restricted in use because of their low sensitivity, high cost of supplies,long analysis cycles,expensive equipment, complex sample preparation and the demand for technical personnel who can use the equipment skillfully, in particular, they cannot conduct on-site analysis and online testing. Therefore, there is an urgent need for an analysis device and method that is rapid, qualitative, quantitative, accurate,sensitive and practical,which is suitable for site and online analysis for monitoring and detection of organic phosphorus pesticide.This paper takes organic phosphorus pesticides as its research object. We prepared a variety of dye-modified electrodes using the adsorption and electropolymerization methods,without the need for enzyme modification. This method can directly detect organic phosphorus pesticides.Its basic contents are as follows:1.We took neutral red dye as a modifier,, using adsorption to modify it to the surface of the glassy carbon electrode,then prepared neutral red film modified electrode,and characterized it by IR spectroscopy, showing that the neutral red monomer did not change before and after its adsorption at the Glassy Carbon Electrode.This paper made a further study of electrochemical acts of the organic monocrotophos phosphorus pesticides on the neutral red-film modified electrode.The experimental results indicated that the response of this modified electrode to monocrotophos has certain catalytic function.Its detection limit is 9.7×10-3μg/mL 2.We took the glassy carbon electrode as the substrate electrode. Then we prepared the poly crystal violet film modified electrode by electrochemical polymerization, and studied the power of monocrotophos in its catalytic activity. Experiments show that this method is simple to use.Its detection limit is up to 0.0086μg/mL.Its reproducibility is 4.31%, significantly higher than that prepared by modified electrode by adsorption method. It's more practicable.It can still maintain 75.7% of activity within 30 days of using this electrode for intermittent detection, thus suitable for on-site and online testing.3.We studied the conditions of preparing polymerization Alizarin red-film modified electrode (PARE)by application of orthogonal testing method. We took parathion as the research object, establishing a electrochemical method for direct determination of parathion by optimizing the experimental conditions.