The Science Behind DisQuE

The QuEChERS procedure is based on an initial single-phase extraction using 10 g or 15 g sample with acetonitrile at 1 mL acetonitrile per 1 g of sample. A liquid-liquid partition is created by adding excess salts and buffers to the extract. After centrifugation, the acetonitrile layer containing the analytes of interest is collected. The sample matrix can be further cleaned and excess water removed with a single d-SPE step by mixing acetonitrile extract with anhydrous MgSO₄ and primary secondary amine (PSA) sorbents. Additional sorbents such as C₁₈ or graphitized carbon black (GCB) could be added as needed for specific matrix cleanup. The final extract can be analyzed directly by either GC-MS or LS-MS/MS with a simple dilution.

Waters DisQuE Dispersive Sample Preparation products include conveniently-packaged centrifuge tubes and foil pouches containing pre-weighed sorbents and buffers for use with both the AOAC (2007.01) and CEN (EN 15662) QuEChERS methods.

Improved Pesticide Analysis

QuEChERS methods were originally developed to extract pesticides from fruits and vegetables. Combining an initial salting out liquid-liquid extraction with d-SPE cleanup, these methods have been demonstrated to be very effective for multi-residue analysis of pesticides, veterinary drugs, and mycotoxins in a wide variety of food and agricultural products. Waters QuEChERS solutions offer numerous advantages over alternative pesticide analysis products and techniques:

• Easy and straightforward methods that require little training
• Decrease in overall sample preparation time
• Consistent and reliable devices from a single vendor
• Efficient, cost effective method which can accommodate a wide variety of commodities
• Improved consistency in extraction products
• Improved lab efficiency and workflow
• Improved quality

Convenient DisQue QuEChERS formats and kits

Complete solutions and kitted methods add value to your laboratory function by addressing the need for simple protocols that require little training to implement. Extraction tubes and pouches, as well as the clean-up tubes, are available separately to support customized applications and greater flexibility. The clean-up tubes are available in the standard 2 mL size as well as a 15 mL size for sample enrichment.

Waters offers several sorbent blends to help remove complex matrix from your sample:

• C₁₈ removes very non-polar interferences, such as fats
• PSA removes polar interferences, including sugars and organic acids

• Graphitized carbon black (GCB) effectively remove pigments such as chlorophyll and carotenoids

• Sorbents including graphitized carbon black and C₁₈ are also available in bulk for methods requiring the removal of excess fat or high amounts of chlorophyll.

Waters offers kits which comply with both AOAC and CEN QuEChERS methods. Alternative sorbent blends to suit your laboratory’s needs may be purchased by special order.