With the development of a modern society, people are increasingly demanding fruits and vegetables, and growers are using pesticides in large quantities to prevent pests and fruits from harming fruits and vegetables, leaving many pesticide residues in fruits and vegetables. At present, there are more than 100 species of organophosphorus pesticides in the world, and there are more than 50 commonly used organic phosphorus pesticides. There are about 30 kinds of organophosphorus pesticides circulating in China. Organophosphorus pesticides are commonly used as pesticides for the prevention and control of pests in vegetables and fruits. However, after a long period of heavy use, residual organophosphorus pesticides can cause acute poisoning or even death of humans or animals through the food chain. They can become teratogenic, carcinogenic, and mutagenic after human body accumulates. They also cause serious pollution and harm to the ecological environment. However, the long-term use of pesticides in large quantities has resulted in significant impacts on the quality and safety of agricultural products. This has directly affected the international competitiveness of China's agricultural products. Therefore, how to effectively control and monitor organophosphorus pesticide residues Contamination, safeguarding the quality and safety of agricultural products, promoting the economic development of agriculture and rural areas, and providing reference for government decision-making have become increasingly important. China's pesticide residue analysis technology began in the 1950s and has undergone rapid development in recent years. China's "Maximum Residue Limits of Pesticides in Foods" stipulates that 13 organophosphorus pesticides such as methamidophos are used in vegetables and grains. The maximum residue limit is 2.3ml GB / T. At the same time in the "determination of organophosphorus pesticide residues in food" is also equipped with the appropriate detection methods. Although there are many detection methods for organophosphorus pesticides such as pesticide residue detectors, they all require pretreatment. The purpose of the pretreatment is to separate the residual pesticide from the sample while minimizing the mixing of impurities outside the pesticide to reduce the impact of the assay. Commonly used treatment methods include impregnation method, chopping method, ultrasonic extraction method, microwave-assisted extraction method, dispersive liquid-phase microextraction technology, and accelerated solvent extraction technology. First, impregnation method: This is the most commonly used and most simple extraction method, that is to say, a certain amount of sample after dehydration and decolorization is placed in a stoppered conical flask, and a suitable organic solvent is added for impregnation for a certain period of time, during which the oscillation is continuously performed or the triangle is The flask was shaken and extracted on a shaker, but the impregnation method was incomplete for extracting components with a strong molecular bond or a solubility in the solvent, and was time consuming. Second, the broken method: mashing method is much more efficient than the impregnation method, the method is also simple, just the sample and extraction solvent together into the tissue masher, with 2 × 104r / min speed extraction One or two minutes is enough, since the sample can be fully contacted with all the solvents while it is crushed, the test substance can be extracted in a short time. The disadvantage is that the extract has occasional emulsification (can be eliminated by centrifugation), and Saltation and secondary extraction, dehydration and concentration are also required for several processes, which are cumbersome and take longer. Third, the microwave-assisted extraction method: microwave energy is through the role of polar molecules in the transmission process, so that the instantaneous molecular polarization of the material, resulting in intermolecular friction, collision, and thus promote the polarization part (measured components) Full contact with the solvent and rapid diffusion to achieve the purpose of separation and extraction. 4. Wave extraction methods: Wave extraction methods are simple, rapid, with low solvent consumption, wide application, high extraction efficiency, and good reproducibility. Dispersed liquid-phase microextraction technology Dispersed liquid-phase microextraction technology is used in recent years. A brand-new sample pretreatment technology has the advantage of using less organic solvent during extraction, generally only ten to several tens of microliters. This method integrates sample collection, extraction, and concentration in one, and is simple, rapid, and enriched. Because the multiple is high, it can be tested directly. While the detection methods of the above several pesticide residue detectors have been continuously developed, some new detection technologies have been continuously proposed and improved, such as living body detection technology, biosensor technology, and immunoassay technology. These detection technologies are Development and application will make China's pesticide residue detection technology a new level.
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