Author(s): Julie Kowalski, Amanda Rigdon, and Jack Cochran
Published By: Separation Science
Issue: vol. 5, issue 8
Year of Publication: 2013
Link: For the full print issue, visit http://www.sepscience.com/docs/Bespoke/Editions/SepSci/Sepsci0813eu.pdf?utm_source=iContact&utm_medium=email&utm_campaign=eLearning%20Newsletter%20-%20Europe%20Sep%20Sci&utm_content=
Abstract: The original QuEChERS sample preparation methods were designed for pesticide residue analysis of high water-content foods, specifically fruits and vegetables. QuEChERS methods provide “just enough” sample preparation because highly selective and sensitive modern instrumentation does not require extremely clean samples. In the first two installments of this series (#1 and #2), official methods were reviewed, as well as considerations for method development. Adjustments to the original methods for some difficult commodities and pesticides were reviewed as well. This article will focus on QuEChERS metamorphosis into a concept. “QuEChERS” will be used as a broad term in this article to describe not only modified QuEChERS methods but also methods based on QuEChERS principles. The success of QuEChERS relates back to the attributes set forth by the originators; Quick, Easy, Cheap, Effective, Rugged and Safe. In addition to these benefits, great flexibility and quick method development have encouraged the expansion of QuEChERS from specific methods to generic techniques, and now to a sample preparation concept.
Author(s): Jaap de Zeeuw
Published By: The Analytical Scientist
Year of Publication: 2013
Abstract: Modern narrow bore columns have made chromatographers lazy when it comes to stationary phase selection. Here’s how getting back to the basics in gas chromatography by using selectivity can address challenging separations and reduce analysis time.
Sourcing individual pesticide standards and preparing working standards is expensive and time-consuming. Food safety laboratories can simplify standard preparation and better ensure data quality by using Restek’s new QuEChERS performance standards kit for initial method evaluation and ongoing performance validation. The QuEChERS performance standards kit was specifically designed to provide low-cost “entry level” mixes for food safety and contract laboratories that want to evaluate the QuEChERS extraction approach (e.g., EN 15662 and AOAC 2007.01) for determining pesticides in fruits and vegetables with GC and LC instrumental methods.
A QuEChERS performance standards kit is ideal for broad class work because it provides a wide range of commonly used organochlorine, organonitrogen, organophosphorus, and carbamate pesticides, while still keeping the total number of analytes to a reasonable level. Volatile, polar, active, base-sensitive, and nonvolatile compounds are included to allow comprehensive evaluation of QuEChERS extraction and cleanup efficiencies, and optimization of GC and LC instrumental conditions.
These multiresidue pesticide standards are precisely formulated to ensure accuracy, and analytes are segregated into mixes based on chemical compatibility for maximum storage stability. Quantitative analysis confirms the composition of each mixture, and documentation for each lot is provided. Restek® QuEChERS performance standards are produced and tested in accordance with ISO Guide 34 and 17025 accreditation.
Restek offers complete solutions for labs running QuEChERS methods. Visit www.restek.com/quechers for addtional QuEChERS reference materials, QuEChERS extraction salts, QuEChERS dispersive SPE cleanup tubes, GC and LC columns and accessories.