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Introduction to qu e chers

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Pradeep Kumar
Pradeep Kumar

This document provides an overview of the QuEChERS method for extracting pesticide residues from high water content food matrices: [1] QuEChERS stands for "Quick, Easy, Cheap, Effective, Rugged, and Safe" and was originally developed in 2001 for veterinary drug residue analysis. It has since been validated as a multiresidue method for pesticide residue analysis in plant materials. [2] The method uses acetonitrile extraction followed by dispersive solid phase extraction (DSPE) for cleanup. DSPE removes water and unwanted contaminants using bulk salts and sorbent mixtures like primary secondary amine (PSA) and magnesium sulfate. [

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Introduction to QuEChERS Pradeep Kumar. G.T
QuEChERS (catchers) Quick Easy Cheap Effective Rugged Safe
Introduction to qu e chers
The QuEChERS-method was developed by Michelangelo in the year 2001 for the analysis of veterinary drugs in animal tissues. After realizing its great potential in the extraction of polar and particularly basic compounds it was also tested on pesticide residue analysis in plant material with great success.
Now QuEChERS is known as a multiclass, multiresidue method (MRM) for analysis of pesticides from high water content (80-95%) matrices. The QuEChERS method now published as AOAC method 2007.01 Determination of Pesticide Residues in Foods by Acetonitrile Extraction and Partitioning with Magnesium Sulfate.
T鞄艶 preferred solvent is acetonitrile because it has been shown to provide extraction of the broadest range of organic compounds without co-extraction of large amounts of lipophilic material. This method is validated for the analysis pesticide residue in dry products like cereals, dried fruits, tea and fatty foods like fish, meat.
Step 1: Sample preparation and extraction Commodities are uniformly ground Extract using required quantity of acetonitrile Centrifuge the extract
Cleaned up using DSPE. Bulk drying salts and DSPE sorbent packings. Remove excess water and unwanted contaminants. Agitation and centrifugation Vortex mixing for 30sec and centrifuge at 3000 rpm for 5min
Freezing out The acetonitrile phase is transferred into a centrifuge tube and stored in a freezer (min 2hrs) removal of lipids, waxes, sugars, and other matrix co-extractives with low solubility in acetonitrile. follow DSPE.
D-SPEwith a PSA/MgSO4- mixture (for most samples) The acetonitrile phase is transferred into a PP- centrifugation tube already containing PSA and magnesium sulfate and agitate.
SPE DSPE (Solid Phase Extraction) (Dispersive Solid Phase Extraction) Required 30 minutes to 1hr Few minutes to complete
This type of cleanup is recommended for extracts of test samples containing more than 50 mg of lipids.
removal of chlorophyll and carotenoids . Samples like red sweet pepper, spinach and vine leaves.
Concentration of the extract in Turbovap evaporator (2 to 5 mL) made up to volume with suitable solvent. For GC n-Hexane is used and for LC methanol. Analysis was done either by GC/MS or LC/MS
Advantage Conventional method QuEChERS Time-Consuming, Complicated Simplified Alternatives or Error-prone Steps Sample No Way Around this Processing/Homogenization Blending/shaking for long time Homogenisation for 30 Sec Filtration Centrifugation Multiple Partitioning Steps Single Partitioning (On-line- Approach) Separation/Transfers of Entire Take Aliquots Extract Use of a Lot of Glassware A few glassware Evaporation/Reconstitution of Evaporation/Reconstitution of large volume small volume Classical Steps/Classical SPE with Dispersive SPE Columns & Manifold
Procedure schematically (for 25 g sample) Weigh 25 g sample into a 250 ml centrifuge bottle (with screw cap) Add 50 ml acetonitrile and shake well
Homogenise for 30 Sec (1st . extraction step) Add 10 g NaCl, shake each tube to dissolve salt. 5g Na2SO4 added to an aliquot From above step an aliquot is transferred to mixture of 0.2g PSA and 0.75g MgSO4
Mix well in vortex (2nd extraction with phase separation) Centrifuge for 5 min at 3000 U/min Aliquot is concentrated and reconstituted.
References www.quechers.com http://www.eurl-pesticides-datapool.eu/
Introduction to qu e chers
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Introduction to qu e chers

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Introduction to qu e chers

  • 1. Introduction to QuEChERS Pradeep Kumar. G.T
  • 4. The QuEChERS-method was developed by Michelangelo in the year 2001 for the analysis of veterinary drugs in animal tissues. After realizing its great potential in the extraction of polar and particularly basic compounds it was also tested on pesticide residue analysis in plant material with great success.
  • 5. Now QuEChERS is known as a multiclass, multiresidue method (MRM) for analysis of pesticides from high water content (80-95%) matrices. The QuEChERS method now published as AOAC method 2007.01 Determination of Pesticide Residues in Foods by Acetonitrile Extraction and Partitioning with Magnesium Sulfate.
  • 6. T鞄艶 preferred solvent is acetonitrile because it has been shown to provide extraction of the broadest range of organic compounds without co-extraction of large amounts of lipophilic material. This method is validated for the analysis pesticide residue in dry products like cereals, dried fruits, tea and fatty foods like fish, meat.
  • 7. Step 1: Sample preparation and extraction Commodities are uniformly ground Extract using required quantity of acetonitrile Centrifuge the extract
  • 8. Cleaned up using DSPE. Bulk drying salts and DSPE sorbent packings. Remove excess water and unwanted contaminants. Agitation and centrifugation Vortex mixing for 30sec and centrifuge at 3000 rpm for 5min
  • 9. Freezing out The acetonitrile phase is transferred into a centrifuge tube and stored in a freezer (min 2hrs) removal of lipids, waxes, sugars, and other matrix co-extractives with low solubility in acetonitrile. follow DSPE.
  • 10. D-SPEwith a PSA/MgSO4- mixture (for most samples) The acetonitrile phase is transferred into a PP- centrifugation tube already containing PSA and magnesium sulfate and agitate.
  • 11. SPE DSPE (Solid Phase Extraction) (Dispersive Solid Phase Extraction) Required 30 minutes to 1hr Few minutes to complete
  • 12. This type of cleanup is recommended for extracts of test samples containing more than 50 mg of lipids.
  • 13. removal of chlorophyll and carotenoids . Samples like red sweet pepper, spinach and vine leaves.
  • 14. Concentration of the extract in Turbovap evaporator (2 to 5 mL) made up to volume with suitable solvent. For GC n-Hexane is used and for LC methanol. Analysis was done either by GC/MS or LC/MS
  • 15. Advantage Conventional method QuEChERS Time-Consuming, Complicated Simplified Alternatives or Error-prone Steps Sample No Way Around this Processing/Homogenization Blending/shaking for long time Homogenisation for 30 Sec Filtration Centrifugation Multiple Partitioning Steps Single Partitioning (On-line- Approach) Separation/Transfers of Entire Take Aliquots Extract Use of a Lot of Glassware A few glassware Evaporation/Reconstitution of Evaporation/Reconstitution of large volume small volume Classical Steps/Classical SPE with Dispersive SPE Columns & Manifold
  • 16. Procedure schematically (for 25 g sample) Weigh 25 g sample into a 250 ml centrifuge bottle (with screw cap) Add 50 ml acetonitrile and shake well
  • 17. Homogenise for 30 Sec (1st . extraction step) Add 10 g NaCl, shake each tube to dissolve salt. 5g Na2SO4 added to an aliquot From above step an aliquot is transferred to mixture of 0.2g PSA and 0.75g MgSO4
  • 18. Mix well in vortex (2nd extraction with phase separation) Centrifuge for 5 min at 3000 U/min Aliquot is concentrated and reconstituted.
  • 21. GCB-Graphitised Carbon Black