QuEChERS is a sample preparation technique that vastly simplifies the analysis of pesticide residues. It's quick, easy, cheap, effective, rugged, and safe. In this video, we'll show you the two primary steps of the QuEChERS method: the extraction of your analytes of interest using extraction salts, followed by the cleanup of your supernatant using dSPE. Let’s get started!
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What is QuEChERS?
From fruits and vegetables to grains, pesticide residue analysis covers a wide variety of commodities. It can be an expensive and time-consuming task, requiring a high level of consistency to deliver reliable results.
QuEChERS is a sample preparation technique that vastly simplifies the analysis of pesticide residues. It’s quick, easy, cheap, effective, rugged, and safe. And it can even be modified to work with other commodities, from analyzing mycotoxins in beer to monitoring pharmaceuticals in fish.
QuEChERS can primarily be thought of as a two-step process: The first step is Extraction, where analytes of interest are extracted from your sample. And the second step is Cleanup, where many potential interferences are removed from the extract. A variety of QuEChERS methods exist to help ensure the efficient extraction of different types of compounds. While these methods vary in specific procedure, the general QuEChERS process follows the same path.
We’ll begin our extraction step by homogenizing the food matrix. This generates a uniform sample that represents the whole product, and improves the extraction efficiency of the desired analytes. Once homogenized, add your sample to a centrifuge tube; then, add the solvent—usually acetonitrile—and shake vigorously. Next add the extraction salts. Shake the tube vigorously again, and now it’s ready to be centrifuged. After the sample has spun down, take a look at your sample. You should see four distinct layers. From the top down, there’s: The Supernatant, The Sample Solids, Water, and Excess Extraction Salt.
During the extraction of your commodity in stage one, other potential interferences, such as sugars, fatty acids, organic acids, pigments, and lipids may still be present. So for stage two, it’s time to use dispersive solid phase extraction media, or dSPE, to clean up your sample. Add your supernatant to the dSPE tube, shake vigorously, and then place it into a centrifuge. Once centrifugation is complete, transfer the supernatant into an autosampler vial and make any final adjustments required for your sample. And that’s it—you’re done! Your sample is now ready to be analyzed.
That’s the power of QuEChERS—a quick, easy, cheap, effective, rugged, and safe sample preparation technique perfectly suited to pesticide analysis. For more information about the QuEChERS approach, visit our website at restek.com/QuEChERS