Preparation method and application of diquat molecularly imprinted polymer microspheres

Abstract

The invention belongs to the technical field of herbicides, and particularly relates to diquat molecularly imprinted polymer microspheres and a preparation method and application thereof. The preparation method is as follows: a mixture of α-methacrylic acid and methyl methacrylate, diquat according to 5 ‑10:1 molar ratio dissolved in solvent, ultrasonication, adding crosslinking agent, filled with nitrogen to deoxygenate, sealed, prepolymerized at 0‑4°C, transferred the prepolymer to the polymerization reactor, added column layer Analyze the silica gel and initiator, shake fully, fill with nitrogen to deoxygenate, and seal; react in a constant temperature water bath oscillator, cool, place in a refrigerator, add hydrofluoric acid, stir, filter, wash, and dry to obtain a solid precipitate; the solid precipitate The substance was extracted with the eluting solvent Soxhlet until the residue of diquat could not be detected in the washing solution, then the washing was stopped and dried to constant weight. The diquat molecularly imprinted polymer microspheres are used as SPE column packing, which can effectively detect the residues of diquat pesticide in plant-derived food and ensure the quality and safety of edible agricultural products.

Description

technical field [0001] The invention belongs to the technical field of herbicides, and in particular relates to a diquat molecularly imprinted polymer microsphere and a preparation method and application thereof. Background technique [0002] Diquat (Diquat, CAS: 2764-72-9, molecular weight: 344.05, molecular formula: C 12 h 12 Br 2 N 2 Its molecular structure is shown in the following formula), which is a bipyridine herbicide first developed and applied in the world by the United Kingdom in 1957. 1,1'-Ethylene-2,2'-bipyridine dibromide belongs to quaternary ammonium salts. Physical and chemical properties: the pure product is colorless to light yellow crystal, vapor pressure <0.01MPa, solubility in water (20°C) is 700g / L, slightly soluble in ethanol and carbonyl solvents, insoluble in non-polar organic solvents, in acidic and Stable in neutral solution, but unstable under alkaline conditions. [0003] Diquat can be quickly absorbed by green plant tissues, and has e...

AI Technical Summary

Problems solved by technology

At present, in the research on the detection method of diquat in relevant crops, solvent extraction such as ethanol and acetonitrile is mainly used, and sodium borohydride is used to reduce it to a partially hydrogenated derivative, thereby reducing polarity and increasing volatility, and then using GC-MS Qualitative and quantitative analysis, but the food or oil system is complicated, the traditional analysis method has poor purification effect, and it is easy to cause unstable test results

[0007] In recent years, some progress has been made in the research on the detection technology of diquat, but the common disadvantages of these methods in practical application are that the pre-processing is complex, cumbersome, time-consuming and expensive

Although solid-phase extraction (SPE) technology is mostly used for the pretreatment of diquat at present, although there are many types of columns, they lack high selectivity, and it is easy to extract the coexisting interfering substances together. For samples with extremely low concentration, the enrichment multiple Limited, does not meet testing requirements

[0008] In view of this, it is necessary to provide a method for preparing diquat molecularly imprinted polymer microspheres to overcome the shortcomings of the pre-treatment extraction and purification steps in the existing diquat detection technology, and to monitor the pesticide residues of diquat , to provide technical support to ensure the quality and safety of agricultural products

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