Pure Chromatography
www.restek.com

QuEChERS Solutions

QuEChERS Made
Even Easier

Comprehensive Solutions Simplify
Sample Prep and Analysis

WELCOME
OVERVIEW
PRODUCTS
RESOURCES
CHROMATOGRAMS

New free-flowing salts in slim packs make extraction a snap.
Complete line of easy-to-use QuEChERS products, reference standards, and accessories.
Follow up sample prep with a wide range of analytical columns for both LC and GC.

Keep your workflow running smoothly with Q-sep extraction salts from Restek!

For years, the QuEChERS approach to sample preparation has been making the lives of food safety scientists easier. Gone are the days of time-consuming, solvent-intensive extraction techniques and multiple solid phase extraction cartridge cleanup steps! Research published by the U.S. Department of Agriculture Easter Regional Research Center in Wyndmoor, PA, [1] introduced to the world QuEChERS—a method that is Quick, Easy, Cheap, Effective, Rugged, and Safe.

With QuEChERS, a homogenized sample undergoes a quick extraction step where the analytes are driven into an organic solvent by the partitioning power of a blend of salts. After extraction, the sample is cleaned up through the use of a dispersive solid phase extraction (dSPE) step that is also quick and easy to perform. This simple, two-stage process offers significant savings in time, materials, and effort, making QuEChERS sample preparation faster and easier than other approaches.

Table I: Prepare samples more quickly, easily, and cost effectively with QuEChERS.

	Mini-Luke or Modified Luke Method	QuEChERS	Savings with QuEChERS
Estimated time to process 6 samples (min)	120	30	4x faster
Solvent used (mL)	60-90	10	6-9x less solvent
Chlorinated waste (mL)	20-30	0	Safer, cheaper, greener
Glassware/specialized equipment	capacity for 200 mL, quartz wool, funnel, water bath, or evaporator	none	Ready-to-use

Since its introduction, the QuEChERS technique has evolved to accommodate an expanding list of pesticides in an increasingly diverse list of foodstuffs. At Restek, we offer Q-sep products to cover the four major approaches to QuEChERS, along with a host of other items to help make your QuEChERS experience simple and successful. We carry a comprehensive line of sample prep supplies, reference standards, and LC and GC columns that will help make QuEChERS even easier, whether you are new to the approach or developing a method for a new sample matrix.

Which product do I choose?

QuEChERS is primarily a two-stage process, and you’ll select Q-sep products for both stages. Your method may have specific recommendations, but in case you’re not sure what will work, here are some considerations when making your selection.

Stage 1: Extraction

The choice of which extraction technique to use is made principally by considering your analytes of interest. If you’re looking for compounds that aren’t pH sensitive, the original unbuffered method [1] will work great. However, if your analytes of interest are pH sensitive, you will want to select one of the buffered methods—notably, the official EN 15662 method [2], the mini-multiresidue approach [3], or the official AOAC 2007.01 method [4].

Restek’s Q-sep products for the two European approaches, the official EN 15662 method and the mini-multiresidue approach, are the same, so it becomes essentially a choice between a European-developed method and the AOAC method. Both are buffered to lower the pH to a range where most pesticides are stable, and the methods differ only in the specific buffering salts and their ratios. Either would be a good place to start for most analyses. There are a great many studies that highlight specific instances when one buffering technique may outperform another, so a little research into your particular area of study may yield practical suggestions on which extraction method to use.

Stage 2: Dispersive Solid Phase Extraction (dSPE) Cleanup

The next big choice comes during the selection of which dSPE cleanup product to use. Where the choice of the extraction product was driven largely by the analytes of interest, the choice of cleanup is based on the sample being tested. Restek Q-sep dSPE products are formulated with different sorbents in different ratios so that your dSPE choice can be tailored to the composition of your particular sample type (e.g., fatty, highly pigmented, etc.). Use Table II to learn what each sorbent removes and to help select the best dSPE product for your particular sample.

Table II: Visit the desktop version of www.restek.com/quechers to access this table.

Table II: Select your dSPE tube based on sample type to ensure you get the best sorbent blend for removing specific matrix interferences.

	Method	Sorbent Mass (mg)				Product Information
		MgSO₄	PSA*	C18-EC	GCB**	Vial Volume (ml)	Cat.#
		Removes
		Excess Water	Sugars, fatty acids, organic acids, anthocyanine pigments	Lipids, nonpolar interferences	Pigments, sterols, nonpolar interferences
General fruits and vegetables (e.g., celery, head lettuce, cucumber, melon)	AOAC 2007.01	150	50	-	-	2	26124
	Original unbuffered, EN 15662, mini-multiresidue	150	25	-	-	2	26215
	AOAC 2007.01	1,200	400	-	-	15	26220
	Original unbuffered, EN 15662	900	150	-	-	15	26223
Foods with fats and waxes (e.g., cereals, avocado, nuts, seeds, and dairy)	Mini-multiresidue	150	25	25	-	2	26216
	-	150	-	50	-	2	26242
	AOAC 2007.01	150	50	50	-	2	26125
	AOAC 2007.01	1,200	400	400	-	15	26221
	-	1,200	-	400	-	15	26244
	-	900	150	150	-	15	26226
Pigmented fruits and vegetables (e.g., strawberries, sweet potatoes, tomatoes)	Mini-multiresidue, EN 15662	150	25	-	2.5	2	26217
	AOAC 2007.01	150	50	-	50	2	26123
	AOAC 2007.01	1,200	400	400	400	15	26222
	EN 15662	900	150	-	15	15	26224
Highly pigmented fruits and vegetables (e.g., red peppers, spinach, blueberries)	Mini-multiresidue, EN 15662	150	25	-	7.5	2	26218
	AOAC 2007.01	150	50	50	50	2	26219
	EN 15662	900	150	-	45	15	26225
	-	900	300	-	150	15	26126
General purpose (wide range of commodities, including fatty and pigmented fruits and vegetables)	-	150	50	50	7.5	2	26243
	-	900	300	300	45	15	26245

Note: No entry in the Method column refers to dSPE formulations not specifically included in one of the cited references. These products can be used to accommodate the various needs of specific matrices not directly met by the cited references.
*PSA = primary secondary amine exchange material
**GCB = graphitized carbon black

References
Restek is not able to provide copies of these documents.
[1] M. Anastassiades, S.J. Lehotay, D. Stajnbaher, F.J. Schenck, Fast and easy multiresidue method employing acetonitrile extraction/partitioning and "dispersive solid-phase extraction" for the determination of pesticide residues in produce. J. AOAC Int. 86 (2003) 412-431. http://pubag.nal.usda.gov/pubag/downloadPDF.xhtml?id=555&content=PDF
[2] EN 15662, Foods of Plant Origin—Determination of Pesticide Residues Using GC-MS and/or LC-MS/MS Following Acetonitrile Extraction/Partitioning and Clean-up by Dispersive SPE—QuEChERS method, 2008.
[3] QuEChERS-A Mini-Multiresidue Method for the Analysis of Pesticide Residues in Low-Fat Products, 2004. http://quechers.cvua-stuttgart.de/pdf/reality.pdf
[4] AOAC Official Method 2007.01, Pesticide Residues in Foods by Acetonitrile Extraction and Partitioning with Magnesium Sulfate, 2007.

Columns

Raptor ARC-18 LC Columns (USP L1)

Ideal for high-throughput LC-MS/MS applications with minimal sample preparation.
Well-balanced retention profile for better detection and integration of large, multiclass analyte lists.
Sterically protected to endure low-pH mobile phases without sacrificing retention or peak quality.
Part of Restek’s Raptor LC column line featuring 1.8, 2.7, and 5 µm SPP core-shell silica.

Rxi-5Sil MS Columns (fused silica)

low-polarity phase; Crossbond 1,4-bis(dimethylsiloxy)phenylene dimethyl polysiloxane

Engineered to be a low-bleed GC-MS column.
Excellent inertness for active compounds.
General-purpose columns—ideal for GC-MS analysis of semivolatiles, polycyclic aromatic compounds, chlorinated hydrocarbons, phthalates, phenols, amines, organochlorine pesticides, organophosphorus pesticides, drugs, solvent impurities, and hydrocarbons.
Temperature range: -60 °C to 350 °C.

Reference Standards

QuEChERS Performance Standards Kit

Designed for use in all QuEChERS methods for pesticides in fruits and vegetables, including the original unbuffered method, AOAC 2007.01, and EN 15662.
Kit contains organochlorine, organonitrogen, organophosphorus, and carbamate pesticides commonly used on fruits and vegetables.
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.
Ideal for initial method evaluations and ongoing method performance validations.
Analytes are divided into three ampuls based on compatibility for maximum stability and shelf life.*
Precise formulations improve data quality and operational efficiency; spend more time running samples and less time sourcing and preparing standards.
Quantitatively analyzed to confirm the composition and stability of each mixture.

*When combining compounds with different functionalities, chemical stability can be an issue. The analytes in this kit are separated into three mixes to ensure maximum long-term storage stability. For analysis, a fresh working standard should be prepared by combining the three kit mixes in a 1:1:1 ratio to prepare a 100 µg/mL working standard solution. Once blended, Restek does not recommend storing working standards or subsequent dilutions for future use.

Contains 1 mL each of these mixtures.
31153: QuEChERS Performance Standard A
31154: QuEChERS Performance Standard B
31155: QuEChERS Performance Standard C

QuEChERS Internal Standards and Quality Control Standards

Single and multiple component standards as specified in EN Method 15662.
Support for GC and HPLC with MS, MS/MS, and selective detectors.
Ready to use for QuEChERS extractions—no dilutions necessary.

LC Multiresidue Pesticide Kit

Accurately detect and quantify pesticides of global food safety concern in a wide range of fruits, vegetables, and other commodities by LC-MS/MS.
Full kit contains 204 compounds of interest, covering many LC-determined pesticides listed by government agencies; individual ampuls also sold separately.

GC Multiresidue Pesticide Kit

Accurately identify and quantify pesticide residues by GC-MS/MS in fruits, vegetables, botanicals, and herbals such as tea, ginseng, ginger, echinacea, and dietary supplements.
Comprehensive 203-compound kit covers food safety lists by the FDA, USDA, and other global governmental agencies; individual ampuls also sold separately.

Sample Handling

Q-sep QuEChERS Extraction Salts

Free-flowing salts transfer easily and completely.
Easy-open packets eliminate the need for a second empty tube for salt transfer.
Convenient slim packets fit perfectly into tubes to prevent spills.
Ready-to-use tubes, no glassware required.
Pre-weighed, ultra-pure extraction salts.
Ideal for original unbuffered, AOAC (2007.01), and European (EN 15662) QuEChERS methods.

Q-sep QuEChERS dSPE Tubes for Extract Cleanup

Fast, Simple Sample Prep for Multiresidue Pesticide Analysis

Packaged in foil subpacks of 10 for enhanced protection and storage stability.
Ready-to-use tubes, no glassware required.
Pre-weighed, ultra-pure sorbents.
Support original unbuffered, AOAC (2007.01), European (EN 15662), and mini-multiresidue QuEChERS methods.

Q-sep 3000 Centrifuge for QuEChERS

Supports 50 mL, 15 mL, and 2 mL centrifuge tubes.
Small footprint requires less bench space.
Safe and reliable—UL, CSA, and CE approved; 1-year warranty.

Q-sep Bottle Top Solvent Dispenser

Adjustment knob offers 56 output volume settings from 2.5 mL to 30 mL per stroke (0.5 mL increments)—ideal for QuEChERS methods!
Base features 30 mm threads and includes five adaptors (28 mm, 32 mm, 36 mm, 40 mm, and 45 mm).
Individually calibrated in accordance with ISO 8655 standards (certificate included) and can also be recalibrated by the user.
PTFE, glass, and polypropylene construction for excellent chemical compatibility and 100% autoclavability.
Integral safety discharge reduces risk of accidental dispensing, and nozzle cap prevents dripping.
Easy to disassemble for cleaning and servicing.

Empty Centrifuge Tubes, Polypropylene

Empty Centrifuge Tubes, FEP

Sturdy, easy-to-clean FEP (fluorinated ethylene propylene)-lined tubes last indefinitely under normal usage conditions—and cost 50% less!

Q-sep Tube Racks

Available for 2 mL, 15 mL, and 50 mL tubes.
Alphanumerical grid reference on top tier for easy identification of samples.
Easy to assemble; simply fold and snap together securely.

Supplies & Accessories

Topaz 4.0 mm ID Single Taper Inlet Liner

for Agilent GCs equipped with split/splitless inlets

Topaz GC inlet liners feature revolutionary technology and inertness to deliver you the next level of True Blue Performance:

Deactivation—unbelievably low breakdown for accurate and precise low-level GC analyses.
Reproducibility—unbeatable manufacturing controls and QC testing for superior reliability across compound classes.
Productivity—unparalleled cleanliness for maximized GC uptime and lab throughput.
100% Satisfaction—if a liner doesn't perform to your expectations, we will replace it or credit your account.*

Patented

Blog
Literature

ChromaBLOGraphy

posted Fri, Jul 24, 2020

LPGC – Fast way to your pesticide analysis!

posted Wed, Jul 01, 2020

Modifying QuEChERS for complicated matrices- High Fat Samples

posted Mon, Jun 15, 2020

QuEChERS approach optimization for low-moisture matrices – case of honey and brown rice flour

View all our QuEChERS blogs...

Literature

Featured Application: Multiresidue Pesticide Mix Extracted from Brown Rice Flour Using QuEChERS Extraction and Cleanup - 7.5-Min Screening Analysis of Multiresidue Pesticides in Brown Rice Flour

Multiresidue pesticides analysis presents many challenges, from extensive lists of chemically diverse analytes to the negative effects of complex matrix components. The optimized chromatographic method described here allows the analysis of hundreds of compounds in as little as 7.5 minutes with a total cycle time under 10 minutes, ensuring fast, accurate sample screening and increased lab productivity.

QuEChERS Bibliography

Evaluation of Dispersive and Cartridge Solid Phase Extraction (SPE) Cleanups for Multiresidue Pesticides in QuEChERS Extracts of Finished Tobacco Using GCxGC-TOFMS

We compared the efficacy of dSPE and cSPE cleanup methods for multiresidue pesticide analysis of QuEChERS extracts of finished tobacco products using GCxGC-TOFMS. Cleanup with dSPE tubes containing 7.5 mg of GCB and 25 mg of PSA produced better results than other methods, with average recoveries of 92% and 91% for 500 ppb and 50 ppb fortifications respectively.

Comparing Pesticide Residues in Amish and Commercially Grown Strawberries and Spinach Using QuEChERS, Various dSPE Sorbents, and GC-TOFMS

QuEChERS extraction, dSPE cleanup, and GC-TOFMS analysis were used to assess pesticide residue levels in strawberry and spinach from both commercial and Amish growers. Various dSPE sorbent products were compared to determine which were most effective.