Introduction to QuEChERS
What is QuEChERS?
QuEChERS (Quick, Easy, Cheap, Effective, Rugged, Safe) is a recent rapid development of a rapid sample preparation technology for agricultural product testing in the world. It was developed by Professor Anastassiades of the US Department of Agriculture in 2003.
The QuEChERS principle is similar to high performance liquid chromatography (HPLC) and solid phase extraction (SPE). It uses the adsorbent filler to interact with impurities in the matrix to adsorb impurities and achieve impurity removal.
The steps of the QuEChERS method
(1) sample pulverization;
(2) single solvent acetonitrile extraction and separation;
(3) addition of MgSO4 and other salts
(4) Adding an adsorbent such as ethylenediamine-N-propylsilane (PSA) to remove impurities;
(5) The supernatant is subjected to GC-MS and LC-MS.
The QuEChERS method’s advantages
(1) high recovery rate, recovery rate of more than 85% for a large number of polar and volatile pesticides;
(2) high accuracy and accuracy, which can be corrected by internal standard method;
(3) A wide range of analyzable pesticides, including polar and non-polar pesticides, can be used to obtain better recovery rate;
(4) fast analysis, can complete 6 samples in 30 minutes;
(5) The solvent is used in a small amount, the pollution is small, the price is low, and the chloride-containing solvent is not used;
(6) the operation is simple and can be completed without good training and high skill;
(7) the acetonitrile is sealed immediately after being added to the container, so that The chance of contact with the staff is reduced;
(8) few glassware is used in the sample preparation process, and the device is simple.
Basic Principles of the QuEChERs Method
The basic principle of the QuEChERs method is similar to that of high performance liquid chromatography (HPLC) and solid phase extraction (SPE). It uses the adsorbent filler to interact with impurities in the matrix to adsorb impurities and achieve the purpose of impurity removal. Specifically, after the homogenized sample is extracted by acetonitrile (or acidified acetonitrile), the salt is separated and layered by extraction salt, the matrix dispersive extraction machine is used, and PSA or other adsorbent and most of the interfering substances in the matrix are used (organic Acid, fatty acid, carbohydrate, etc. are combined and removed by centrifugation to achieve purification.
There are many applications for the QuEchERS method. As long as the recovery rate of the target to be tested meets the demand, and the matrix background of the impurity removal meets the detection requirements, the method can be used to purify the food residue, animal residue, additives, and illegal. Additives, plasticizers, and all areas may be involved. However, the current QuEchERS method is mainly used in the detection of pesticide residues in agricultural products.
The Development of QuEChERS
R & D background
How to make trace analysis of complicated sample matrices and how to do sample pretreatment have become great challenges in the industry. In order to meet the demand of the global increasing population, food production improves rapidly and multiple pesticides are also widely used. Therefore, inspectors must keep improving the detection technique to make trace analyses.
Nowadays, in order to meet the growing needs of the world’s population, food production has been greatly improved, which has led to the use of a variety of toxic pesticides.
The application of pesticides sometimes appears to be “next to miss, can’t be let go”. Even if the agricultural products themselves are not needed, they will be cast. Therefore, for the trace detection of these pesticides, the testing workers must continuously improve their testing techniques. Therefore, the pesticide residue analysis method for many types of pesticides has been paid attention to.
The traditional technology of sample treatment has gone through stages of liquid-solid extraction, liquid-liquid extraction, and solid-phase extraction. In the year 2003, chemists in the United States Department of Agriculture invented an effective method to separate trace pesticide residues from all kinds of fruit and vegetables. In cooperation with the high sensitivity and selectivity of hygroplasm and gas, QuEChERS technology has obtained grand development. After extraction with acetonitrile of solid sample in the aqueous solution, most distractions existing in acetonitrile can be removed by liquid-solid extraction afterward. Finally, you can make a mass spectrometric analysis of the extracted liquor directly.
With the development of high-throughput, high-sensitivity, and high-selectivity liquid chromatography-mass spectrometry and gas chromatography-mass spectrometry, the application of QuEChERS technology has made great progress in recent years. The solid sample in the aqueous solution is salted and then extracted with acetonitrile, followed by liquid-solid extraction (ie, dispersion matrix extraction) to remove most of the interfering substances present in the acetonitrile, and the extract can be directly subjected to mass spectrometry.
Now QuEChERS has become the standard sample processing method for detecting pesticide residues in fruits and vegetables worldwide. In addition, its application involves more and more different fields, such as meat, blood samples, wine, and even soil antibiotics, drugs, drugs of abuse, and other pollution detection.
QuEChERS technology has only been available for several years, but it has brought innovations in areas such as multi-residue analysis and multi-class pesticide analysis. Columnist Ron Majors interviewed the inventors of QuEChERS, Michelangelo Anastassiades, and Steve Lehotay, to discuss their achievements, challenges, and future directions in the ever-changing sample processing technology.
Recently, QuEChERS has become the standard sample treatment method to test pesticide residues of fruit and vegetables globally. In addition, the technology is now touching upon more and more different industries, such as the test of meat, blood sample, wine, antibiotics in the soil, drug, and other pollutants.