Sample Preparation

UCT QuEChERS

QuEChERS (pronounced Catchers), an acronym for Quick, Easy, Cheap, Effective, Rugged and Safe, is a sample extraction and clean-up technique widely used for the analysis of multiple residues in hydrated agricultural products.

Originally designed for the analysis of fruits and vegetables, QuEChERS now includes a wide range of agricultural products. Since its development and publication by scientists at the USDA in 2003, QuEChERS has gained significant popularity as the method of choice. It combines several sample preparation steps and extends the range of analytes recovered over older, tedious extraction methods. A driving force in the growth of QuEChERS is the emerging need to determine trace amounts of analytes in a high throughput environment.

Matrices include:

• animal products–meat, fish, kidney, chicken, milk, honey
• cereals and grain products
• food products–wines, juices, fruit and vegetables

The expansion of the QuEChERS methodology indicates not only its power for sample extraction and clean-up but also addresses the concern about detecting a vast array of pesticides, herbicides, fungicides, antibiotics, and other compounds throughout the entire food supply. QuEChERS in its basic form involves three steps:

1. liquid micro-extraction
2. solid-phase clean-up
3. LC/MS/MS or GC/MS analysis

QuEChERS continues to undergo modifications for improved sample preparation in a broad array of analytes in a vast array of matrices. Due to the large number of QuEChERS methods now published, QuEChERS is considered an “approach” rather than a “method.” QuEChERS has now become a generic technique with many modifications, each variation is designed to accomplish one thing—quick sample extraction and clean-up. Modifications to the original QuEChERS method have been introduced to:

• increase sample throughput while reducing costs
• minimize degradation of susceptible compounds (e.g. base and acid labile pesticides)
• expand the range of matrices amenable by this approach