# QuEChERS

QuEChERS (quick, easy, cheap, effective, rugged, and safe) is a sample-preparation method in analytical chemistry that isolates pesticide residues and other contaminants from food and environmental samples by salting-out extraction with acetonitrile, followed by dispersive solid-phase extraction (dSPE) cleanup.<sup>[1](https://doi.org/10.1093/jaoac/86.2.412)</sup> It produces a clean acetonitrile extract that can be injected directly, after simple dilution, into GC-MS or LC-MS/MS instruments, and the same extract can serve both GC and LC analysis.<sup>[2](https://pubmed.ncbi.nlm.nih.gov/21643905/)</sup><sup> • </sup><sup>[3](https://www.sciencedirect.com/science/article/abs/pii/S221415881830028X)</sup> Extraction of a homogenized sample takes less than 30 minutes, cleanup less than 30 minutes more, and in most cases no concentration step is needed.<sup>[3](https://www.sciencedirect.com/science/article/abs/pii/S221415881830028X)</sup> These traits made it a very flexible multiresidue method for pesticide analysis in produce, and two buffered versions hold official status as AOAC Official Method 2007.01 and CEN Standard Method EN 15662.<sup>[2](https://pubmed.ncbi.nlm.nih.gov/21643905/)</sup>

| Key fact | Detail |
|---|---|
| What the acronym means | Quick, Easy, Cheap, Effective, Rugged, and Safe<sup>[2](https://pubmed.ncbi.nlm.nih.gov/21643905/)</sup> |
| Product | A cleaned acetonitrile extract for GC-MS and LC-MS/MS, usable for both in parallel<sup>[2](https://pubmed.ncbi.nlm.nih.gov/21643905/)</sup><sup> • </sup><sup>[3](https://www.sciencedirect.com/science/article/abs/pii/S221415881830028X)</sup> |
| Core chemistry | Salting-out of acetonitrile from water with MgSO₄ and NaCl, then dSPE with PSA, C18, and optionally GCB<sup>[4](https://phenomenex.blob.core.windows.net/documents/4d3b8d56-2072-4df0-951e-3ed29e39530f.pdf)</sup><sup> • </sup><sup>[5](https://pmc.ncbi.nlm.nih.gov/articles/PMC5757139/)</sup> |
| Official versions | AOAC 2007.01 (acetate buffer) and EN 15662 (citrate buffer)<sup>[2](https://pubmed.ncbi.nlm.nih.gov/21643905/)</sup> |
| Typical recoveries | Mostly 70–120% with RSD ≤ 20% across matrices at 0.005–0.050 mg/kg<sup>[6](https://www.eurl-pesticides.eu/userfiles/file/EurlFV/methods/EURL-FV%20%282022-M52%29.pdf)</sup> |
| Throughput and cost | 10 chopped samples in about 30 minutes, about $1 of materials per sample<sup>[7](https://agresearchmag.ars.usda.gov/ar/archive/2003/jul/quech0703.pdf)</sup> |
| Solvent waste | Under 10 mL per sample, versus 75–450 mL for other methods<sup>[7](https://agresearchmag.ars.usda.gov/ar/archive/2003/jul/quech0703.pdf)</sup> |

## How it works

The method rests on the partition behavior of acetonitrile in a salted aqueous matrix. Adding anhydrous magnesium sulfate absorbs water and increases the ionic strength of the aqueous phase, which induces phase separation between acetonitrile and water; the acetonitrile layer carries the analytes.<sup>[4](https://phenomenex.blob.core.windows.net/documents/4d3b8d56-2072-4df0-951e-3ed29e39530f.pdf)</sup> [Acetonitrile](https://www.edgepedia.org/acetonitrile) is the solvent of choice because it separates from water by salt partitioning, extracts fewer matrix interferences than alternatives, and the resulting extract suits both GC and LC injection.<sup>[5](https://pmc.ncbi.nlm.nih.gov/articles/PMC5757139/)</sup> The MgSO₄/NaCl combination gave the most effectively tailored phase separation, avoiding co-extraction of proteins and sugars.<sup>[8](https://www.chromatographyonline.com/view/the-quecherser-mega-method)</sup>

The cleanup step is dispersive SPE: sorbent powder is added directly to a subsample of the extract. PSA (primary secondary amine) removes sugars, fatty acids, organic acids, and anthocyanin pigments; C18 removes nonpolar interferences such as fats and oils; GCB (graphitized carbon black) removes pigments, sterols, and nonpolar interferences; MgSO₄ removes residual water.<sup>[9](https://discover.restek.com/wp-content/uploads/FSAR3917.pdf)</sup><sup> • </sup><sup>[10](https://www.waters.com/nextgen/us/en/products/sample-preparation/disque--quechers-sample-preparation-products.html)</sup>

## How it is done

All versions follow two stages: extraction with solvent and salts, then dSPE cleanup of a subsample of the organic layer.<sup>[11](https://discover.restek.com/wp-content/uploads/803-01-005.pdf)</sup>

Original unbuffered and EN 15662 (citrate): weigh 10 g of homogenized sample, add 10 mL acetonitrile, then a salt packet of 4 g anhydrous MgSO₄ plus 1 g NaCl (unbuffered) or that plus 1 g trisodium citrate dihydrate and 0.5 g disodium hydrogen citrate sesquihydrate (citrate-buffered).<sup>[12](https://www.go-jsb.co.uk/resources/media/assortiment/manuals/Lehotay_etal_Comparison_various_QuEChERS_extractions_2010_J_Chrom_A_40852PDF1944.pdf)</sup><sup> • </sup><sup>[6](https://www.eurl-pesticides.eu/userfiles/file/EurlFV/methods/EURL-FV%20%282022-M52%29.pdf)</sup> The tube is shaken and centrifuged (EN 15662 specifies over 3000 × g for 5 minutes).<sup>[13](http://global.shimadzu-sglc.com/sites/default/files/pdf/2026-01/SGLC-SPE-006A%20SHIMSEN%20QuEChERS_0.pdf)</sup> EN 15662 also calls for pH adjustment with 5 N NaOH before extraction if the sample pH is below 5 (600 µL below pH 3, 200 µL between pH 3 and 5).<sup>[11](https://discover.restek.com/wp-content/uploads/803-01-005.pdf)</sup>

AOAC 2007.01 (acetate): weigh 15 g of sample, add 15 mL of 1% acetic acid in acetonitrile and a packet of 6 g anhydrous MgSO₄ plus 1.5 g anhydrous sodium acetate, shake, and centrifuge.<sup>[11](https://discover.restek.com/wp-content/uploads/803-01-005.pdf)</sup><sup> • </sup><sup>[14](https://gcms.labrulez.com/labrulez-bucket-strapi-h3hsga3/application::paper.paper/5378f26f-a27c-4e65-b4b4-d7f73bc2fa73.pdf)</sup>

Cleanup: transfer a portion of the acetonitrile layer to a tube with 150 mg anhydrous MgSO₄ plus 50 mg PSA per mL of extract, shake, and centrifuge again.<sup>[15](https://doi.org/10.1093/jaoac/88.2.615)</sup> Dry commodities such as cereals, dried fruits, or tea need water added before extraction, generally to a roughly 1:1 water-to-solvent ratio (about 10–15 mL total water), to weaken analyte-matrix interactions and ensure partitioning.<sup>[16](https://www.quechers.eu/method)</sup><sup> • </sup><sup>[9](https://discover.restek.com/wp-content/uploads/FSAR3917.pdf)</sup> The final extract is analyzed directly by GC-MS or LC-MS/MS after simple dilution.<sup>[10](https://www.waters.com/nextgen/us/en/products/sample-preparation/disque--quechers-sample-preparation-products.html)</sup>

## Origin

QuEChERS was introduced in 2003 by Michelangelo Anastassiades and colleagues, in the paper "Fast and Easy Multiresidue Method Employing Acetonitrile Extraction/Partitioning and 'Dispersive Solid-Phase Extraction' for the Determination of Pesticide Residues in Produce," published in the Journal of AOAC International.<sup>[1](https://doi.org/10.1093/jaoac/86.2.412)</sup> The acetate-buffered variant, the basis of AOAC Official Method 2007.01, was introduced by Steven J Lehotay, Kateřina Maštovská, and Alan R Lightfield in the Journal of AOAC International in 2005.<sup>[15](https://doi.org/10.1093/jaoac/88.2.615)</sup> Maštovská, Lehotay, and Anastassiades introduced analyte protectants to overcome GC matrix effects in Analytical Chemistry in 2005.<sup>[17](https://doi.org/10.1021/ac0515576)</sup> Uptake was rapid: from publication in March 2003 to March 2023 the introducing paper received almost 4,000 citations in [Web of Science](https://www.edgepedia.org/web-of-science), and both buffered versions met interlaboratory performance criteria to achieve official status as AOAC Official Method 2007.01 and CEN Standard Method EN 15662.<sup>[18](https://link.springer.com/article/10.1007/s44169-024-00073-1)</sup><sup> • </sup><sup>[2](https://pubmed.ncbi.nlm.nih.gov/21643905/)</sup>

## Variants

The three main versions differ in their salt packets: unbuffered uses 4 g MgSO₄ plus 1 g NaCl per 10 g sample; acetate-buffered uses 6 g MgSO₄ plus 1.5 g sodium acetate; citrate-buffered adds 1 g trisodium citrate dihydrate and 0.5 g disodium hydrogen citrate sesquihydrate to the unbuffered salts.<sup>[12](https://www.go-jsb.co.uk/resources/media/assortiment/manuals/Lehotay_etal_Comparison_various_QuEChERS_extractions_2010_J_Chrom_A_40852PDF1944.pdf)</sup> AOAC salts buffer the final extract to about pH 4.75 and EN salts to pH 5.0–5.5, while with unbuffered salts the extract pH follows the sample.<sup>[9](https://discover.restek.com/wp-content/uploads/FSAR3917.pdf)</sup> In a three-way comparison of 32 pesticides in apple-blueberry sauce, peas, and limes at 50–1000 ng/g, all versions gave an overall average recovery of 98% with 10% RSD, except that the unbuffered method gave lower recoveries for pH-dependent pesticides.<sup>[12](https://www.go-jsb.co.uk/resources/media/assortiment/manuals/Lehotay_etal_Comparison_various_QuEChERS_extractions_2010_J_Chrom_A_40852PDF1944.pdf)</sup> In soil, the acetate version gave average recoveries of 72–121% (RSD < 19%), the citrate version 67–123% (RSD < 15%), and the unbuffered method fell below 70% for about 30% of 58 pesticides.<sup>[19](https://www.mdpi.com/1420-3049/27/13/4323)</sup> Cleanup can also use mini-cartridge SPE instead of dSPE; a cited effective dSPE mixture for fruits and vegetables is 150 mg MgSO₄, 50 mg PSA, 50 mg C18, and 7.5 mg GCB per mL of extract with acetate buffering.<sup>[20](https://www.sciencedirect.com/science/article/abs/pii/S0021967310006382)</sup> Zirconium-oxide sorbents (Z-Sep, Z-Sep+) combined with C18 and PSA improve cleanup of high-fat samples, and ChloroFiltr removes more than 82% of chlorophyll without loss of planar compounds.<sup>[5](https://pmc.ncbi.nlm.nih.gov/articles/PMC5757139/)</sup><sup> • </sup><sup>[18](https://link.springer.com/article/10.1007/s44169-024-00073-1)</sup> Micro-QuEChERS reduces sample mass to 5 g or less, a reduction of at least half versus conventional protocols that use 10–15 g of matrix, cutting solvent and sorbent waste.<sup>[21](https://www.mdpi.com/2297-8739/12/12/339)</sup> The QuEChERSER "megamethod" adds "efficient and robust" to the acronym and covers a broader polarity range of analytes in diverse matrices, using 1–5 g samples extracted with 5 mL/g of 4:1 acetonitrile-water and automated instrument-top mini-cartridge cleanup of 45 mg MgSO₄/PSA/C18/CarbonX per 300 µL extract.<sup>[18](https://link.springer.com/article/10.1007/s44169-024-00073-1)</sup><sup> • </sup><sup>[8](https://www.chromatographyonline.com/view/the-quecherser-mega-method)</sup>

## Applications

QuEChERS has been extended to pharmaceuticals, polycyclic aromatic hydrocarbons (PAHs), and persistent organic pollutants including dioxins, [polychlorinated biphenyls](https://www.edgepedia.org/polychlorinated-biphenyl), perfluoroalkyl substances, and brominated flame retardants in food, biological, and environmental matrices.<sup>[3](https://www.sciencedirect.com/science/article/abs/pii/S221415881830028X)</sup> For PAHs in fatty fish, a variant using ethyl acetate, acetone, and isooctane attained overall recoveries almost 40% higher than [Soxhlet extraction](https://www.edgepedia.org/soxhlet-extraction), and QuEChERS determined PCBs in fish with LOQs below 1 ng/g.<sup>[5](https://pmc.ncbi.nlm.nih.gov/articles/PMC5757139/)</sup> In QuEChERS-based PFAS methods, acetonitrile was the extraction solvent in 95% of reviewed methods, with mild acidification (0.1–1.5% formic or acetic acid) improving recovery of the organic phase.<sup>[22](https://iris.unimore.it/retrieve/a4c8e2eb-8ea8-400d-a18f-e91c0188c71d/foods-Galluzzo%20may2026.pdf)</sup>

## Limitations and alternatives

In an EURL validation across zucchini, orange, and avocado at 0.005 and 0.050 mg/kg, most recoveries for 33 pesticides fell within 70–120% with RSD ≤ 20% using citrate-buffered QuEChERS.<sup>[6](https://www.eurl-pesticides.eu/userfiles/file/EurlFV/methods/EURL-FV%20%282022-M52%29.pdf)</sup> Against traditional methods, QuEChERS offers at least fourfold lower material costs and fourfold greater throughput per analyst, and generates under 10 mL of solvent waste versus 75–450 mL.<sup>[7](https://agresearchmag.ars.usda.gov/ar/archive/2003/jul/quech0703.pdf)</sup> Its main trade-off against conventional SPE is enrichment: micro-QuEChERS gives enrichment factors of 10–50 for PAHs in water versus 100–1000 for SPE.<sup>[21](https://www.mdpi.com/2297-8739/12/12/339)</sup>

Known failure modes include hydrophilic analytes that do not partition into the acetonitrile layer during salting-out, PSA that retains LC-amenable carboxylic acid analytes, and acetonitrile-rich extracts that give poor peak shapes for early-eluting compounds in reversed-phase LC.<sup>[8](https://www.chromatographyonline.com/view/the-quecherser-mega-method)</sup> PSA's basicity can hydrolyze alkali-sensitive pesticides; more than half of 25 herbicides in one study lost 23–80% recovery with 50 mg PSA per mL, while 50 mg C18 per mL achieved 72–108%.<sup>[19](https://www.mdpi.com/1420-3049/27/13/4323)</sup> GCB strongly retains planar pesticides such as thiabendazole and chlorothalonil.<sup>[18](https://link.springer.com/article/10.1007/s44169-024-00073-1)</sup> Highly non-polar pesticides in fatty matrices give low but consistent recoveries below 70%,<sup>[16](https://www.quechers.eu/method)</sup> and PSA's anion-exchange properties can retain ionizable PFAS, dropping recoveries below 50% for some carboxylates at high PSA amounts.<sup>[22](https://iris.unimore.it/retrieve/a4c8e2eb-8ea8-400d-a18f-e91c0188c71d/foods-Galluzzo%20may2026.pdf)</sup> On the green-chemistry side, natural deep eutectic solvents (NADES) have been benchmarked against QuEChERS: a thymol:menthol (1:1) extraction for eleven pesticides in orange, wheat, and spinach scored 0.65 on the AGREEprep greenness metric, above both AOAC 2007.01 and a miniaturized QuEChERS, with LOQs of 10 µg/kg and no salting-out or cleanup steps; the driver is partly acetonitrile's toxicity profile, which is classified as problematic for safety, health, and environment.<sup>[23](https://link.springer.com/article/10.1038/s41538-026-00717-7)</sup>

## References

1. [Michelangelo Anastassiades and colleagues (2003). Fast and Easy Multiresidue Method Employing Acetonitrile Extraction/Partitioning and “Dispersive Solid-Phase Extraction” for the Determination of Pesticide Residues in Produce. Journal of AOAC International.](https://doi.org/10.1093/jaoac/86.2.412)
2. [QuEChERS sample preparation approach for mass spectrometric analysis of pesticide residues in foods (Lehotay, 2011, Methods Mol Biol)](https://pubmed.ncbi.nlm.nih.gov/21643905/)
3. [Review of the QuEChERS method for the analysis of organic pollutants: Persistent organic pollutants, polycyclic aromatic hydrocarbons, and pharmaceuticals (Trends in Environmental Analytical Chemistry, 2019)](https://www.sciencedirect.com/science/article/abs/pii/S221415881830028X)
4. [Frequently Asked Questions (FAQ), QuEChERS (Phenomenex)](https://phenomenex.blob.core.windows.net/documents/4d3b8d56-2072-4df0-951e-3ed29e39530f.pdf)
5. [Application of QuEChERS for Determining Xenobiotics in Foods of Animal Origin (J AOAC Int / PMC)](https://pmc.ncbi.nlm.nih.gov/articles/PMC5757139/)
6. [EURL FV (2022 M52) (eurl-pesticides.eu)](https://www.eurl-pesticides.eu/userfiles/file/EurlFV/methods/EURL-FV%20%282022-M52%29.pdf)
7. [QuEChERS Method Catches Pesticide Residues (Agricultural Research, July 2003)](https://agresearchmag.ars.usda.gov/ar/archive/2003/jul/quech0703.pdf)
8. [The QuEChERSER Mega-Method (LCGC, article by the method's co-developer)](https://www.chromatographyonline.com/view/the-quecherser-mega-method)
9. [How to Use QuEChERS for Diverse Sample Types (Restek application note)](https://discover.restek.com/wp-content/uploads/FSAR3917.pdf)
10. [DisQuE, QuEChERS Sample Preparation Products (Waters)](https://www.waters.com/nextgen/us/en/products/sample-preparation/disque--quechers-sample-preparation-products.html)
11. [QuEChERS Sample Preparation Procedures (Restek)](https://discover.restek.com/wp-content/uploads/803-01-005.pdf)
12. [Comparison of QuEChERS sample preparation methods for the analysis of pesticide residues in fruits and vegetables (Lehotay et al., J. Chromatogr. A 1217 (2010) 2548–2560)](https://www.go-jsb.co.uk/resources/media/assortiment/manuals/Lehotay_etal_Comparison_various_QuEChERS_extractions_2010_J_Chrom_A_40852PDF1944.pdf)
13. [SHIMSEN QuEChERS Product Guidebook (Shimadzu)](http://global.shimadzu-sglc.com/sites/default/files/pdf/2026-01/SGLC-SPE-006A%20SHIMSEN%20QuEChERS_0.pdf)
14. [roQ QuEChERS Kits User Guide (manufacturer protocol document)](https://gcms.labrulez.com/labrulez-bucket-strapi-h3hsga3/application::paper.paper/5378f26f-a27c-4e65-b4b4-d7f73bc2fa73.pdf)
15. [Steven J Lehotay, Kateřina Maštovská, Alan R Lightfield (2005). Use of Buffering and Other Means to Improve Results of Problematic Pesticides in a Fast and Easy Method for Residue Analysis of Fruits and Vegetables. Journal of AOAC International.](https://doi.org/10.1093/jaoac/88.2.615)
16. [QuEChERS: About the method](https://www.quechers.eu/method)
17. [Kateřina Maštovská, Steven J. Lehotay, Michelangelo Anastassiades (2005). Combination of Analyte Protectants To Overcome Matrix Effects in Routine GC Analysis of Pesticide Residues in Food Matrixes. Analytical Chemistry.](https://doi.org/10.1021/ac0515576)
18. [Overview of the Evolution and Trends of the QuEChERS Sample Preparation Procedure (Reviews of Environmental Contamination and Toxicology, 2024)](https://link.springer.com/article/10.1007/s44169-024-00073-1)
19. [Pesticide-Residue Analysis in Soils by the QuEChERS Method: A Review (Molecules, 2022)](https://www.mdpi.com/1420-3049/27/13/4323)
20. [High throughput analysis of 150 pesticides in fruits and vegetables using QuEChERS and low-pressure GC–TOFMS (J. Chromatogr. A)](https://www.sciencedirect.com/science/article/abs/pii/S0021967310006382)
21. [Towards Greener Sample Preparation: A Review on Micro-QuEChERS Advances and Applications in Food, Environmental, and Biological Matrices (Separations 12(12):339)](https://www.mdpi.com/2297-8739/12/12/339)
22. [QuEChERS-Based LC-MS/MS and HRMS Methods for PFAS Determination in Food: A Systematic Review (Foods, 2026; repository copy)](https://iris.unimore.it/retrieve/a4c8e2eb-8ea8-400d-a18f-e91c0188c71d/foods-Galluzzo%20may2026.pdf)
23. [Natural deep eutectic solvents as a sustainable alternative for multi-class pesticide extraction in food safety analysis (npj Science of Food, 2026)](https://link.springer.com/article/10.1038/s41538-026-00717-7)

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*Topic: Encyclopedia › Physical world and mathematics › Chemistry › Chemical principles and methods › Analytical chemistry › Extraction and sample preparation*

*Initially written Sep 29, 2026 · Edited: Oct 15, 2026; Oct 25, 2026*

*Copyright 2026 EdgeChat AI, a subsidiary of Biostate AI.*

License: Edgepedia Community License 1.0, https://www.edgepedia.org/edgepedia/license