Application Of QuEChERS Method In The Detection
Concept of the QuEChERS method
QuEChERS is a new multi-residue sample processing method, and has the advantages of simplicity, convenience, economy, safety, and reliability, and is mainly suitable for detection of agricultural and veterinary drugs and papaverine in various fruits, vegetables, meat, hot pot bottoms. In recent years, research scholars have carefully analyzed the QuEChERS method and gradually expanded the application range of the method. Now, the QuEChERS method has become the preferred method for the detection of hundreds of agricultural and veterinary drug residues.
Composition of the QuEChERS method
When the technicians establish the QuEChERS method, they mainly choose three kinds of agents, namely extractant, dehydrating agent and purifying agent. Grasping the composition of the QuEChERS method can serve as a theoretical foundation for the analysis of the advantages and the application of the QuEChERS method.
Advantages of the QuEChERS method
The QuEChERS method features a short detection cycle, simple operation and batch production, high accuracy, and precision. The feasibility of detecting samples is very high; there are fewer solvents and waste liquids generated, and the containers and utensils can be reused multiple times without causing resource waste while reducing application costs. In a word, the QuEChERS method is convenient, fast, reliable and safe.
Application in pesticide residue detection
The first application of the QuEChERS in the detection of pesticide residues in fruits and vegetables was in 2003. The method was simple to operate and low in cost. In order to conduct more in-depth research, the researchers tested the QuEChERS method on more than a dozen different foods. In the process of using the QuEChERS method, first, extract anhydrous magnesium sulfate and sodium chloride with acetonitrile, and then purify some fruits and vegetables. The chemical solution after purification is PSA and anhydrous magnesium sulfate. According to the experimental results, it is found that the pH and stability of these fruits and vegetables have changed due to the influence of chemical solutions, especially the stability has been significantly reduced.
Lehotay et al found in the experiment that when the pH value of the pesticide is 5, agriculture has a higher recovery rate, but it has no obvious relationship with the matrix of fruits and vegetables. Afterward, on this basis, it can be determined through experiments that there are two main methods of QuEChERS, namely, acetic acid buffered QuEChERS method with greater ionic strength and citrate buffered QuEChERS method with lower ionic strength. After the confirmation of many experiments, the acetic acid buffered QuEChERS method has been internationally recognized and has become the standard test method for fruits and vegetables. Both of these methods have played an important role in food safety.
Lee et al. used dry ice instead of buffer for extraction, which improved the recovery rate of pepper pesticide residues. Chen B et al. used chloroform instead of sodium chloride to solve the problem of low recovery in polarity analysis. Hu Jingrong improved the QuEChERS method, which has the characteristics of short extraction time, low solvent consumption, and high extraction efficiency, and improves the detection efficiency. The recovery rate of 18 pesticides in Chinese cabbage was 90% ~ 108%. The detection limit of the method is 0.02 ~ 55.75μg·kg-1, and the limit of quantification is 0.1 ~ 189.23μg·kg-1.