QuEChERS Clean-up Tubes-2 ml, AOAC Method, 150 mg mgSO4, 50 mg PSA, 50 g C18E, 50 mg GCB, 100 St/Pkg

QuEChERS (ausgesprochen „catchers“) steht für Quick, Easy, Cheap, Effective, Rugged und Safe – die Eigenschaften, die diese Probenvorbereitungsmethode für Lebensmittelsubstanzen beschreiben. Die Technik ist recht einfach, erfordert ein Minimum an Schritten und eignet sich effektiv für die Reinigung komplexer Proben. QuEChERS ist eine aktualisierte Version von SPE. Sie haben ähnliche Funktionen, aber die Zubereitungsmethode von QuEChERS ist viel einfacher. Mit QuEChERS können Sie Ihre Proben für die Analyse mehrerer Klassen und Rückstände vorbereiten und dabei Zeit und Geld sparen. In den Vereinigten Staaten hat die Association of Official Analytical Chemists (AOAC) ihre Methode 2007 .01 veröffentlicht, während das europäische Äquivalent, die EN 15662 2007, eine ähnliche Methodik verwendet.

AOAC, EN methods add buffer salts in the original OR method to ensure effective extraction of pH-sensitive compounds, to reduce degradation of sensitive compounds (such as pesticides that are not stable to alkali or acid), and to expand the application range of broad spectrum of this method for food matrices. In the first step of extraction, citrate is used as a buffer to adjust pH to 5-5.5, allowing most pesticides that are not stable to acid or alkali to remain stable. For alkali-sensitive compounds, the stability can be improved by adding a small amount of formic acid after cleanup. For target compounds containing acidic pesticides (phenoxy alcohols), sample injection analysis can be performed directly (skipping the SPE dispersion step), as the acidic group binds to the PSA adsorbent, resulting in reduced recovery rate. For dry samples such as cereals, dried fruits, tobacco, or tea, water should be added before the extraction to reduce the interaction between pesticide and matrices to ensure adequate phase separation. Even high-fat samples such as avocados or olive oil can be analyzed this way. However, for strong nonpolar pesticides, the recovery rate can only reach 70% due to phase separation entered lipid phase. Those lipids extracted together can be removed by freezing or adding a C18E adsorbent.
Nowadays, QuEChERS method has been applied in more and more fields, such as detection of PAHs in meat products, detection of various veterinary drug residues, detection of dicyandiamide, etc. The development of these applications has greatly reduced the pretreatment workload of chromatographers.