QuEChERS Method for Pesticide Residue Analysis

QuEChERS significantly improves laboratory efficiency and throughput. This procedure requires only small quantities of solvent and is capable of generating recoveries of 70-120% with RSDs <5% for a wide range of compounds.

A process in two steps:

1. Extraction

• Solvent extraction techniques are designed to achieve maximum yield of analytes from the base matrix.
• Solvent selection is important to minimize co-extracting compounds.
• Analytes are extracted from the matrix with acetonitrile and salts/buffers.

2. Cleanup

• Sample cleanup is necessary to reduce interferences.
• Interferences can damage analytical instrumentation and complicate analyte identification and quantification.
• The use of PSA, C18, GCB (Graphitized Carbon Black) or Z-Sep sorbents allow removal of sugars, lipids, sterols, organic acids, proteins, carotenoids, chlorophyll and other pigments prior to a GC-MS/MS or LC-MS/MS analysis.

1. Homogenize sample
2. Transfer sample to 50mL tube
3. Add ACN and internal standard and shake for 1 min
4. Extraction: Add extraction salts and centrifuge (55227-U for EN15662:2008 and 55234-U for 2007.01 AOAC)
5. Cleanup: Transfer supernatant to cleanup tube
6. Shake and centrifuge
   a) LC-MS/MS Analysis: Dilute extract with mobile phase
   b) GC-MS analysis: Analyze directly or after solvent exchange

QuEChERS Selection Guide

Products for the Extraction Step

Description	Quantity	Cat. No.
Method EN15662 :2008 (12 mL centrifuge tubes)
Supel™ QuE Citrate (EN) Tube – 4 g MgSO4, 1 g NaCl, 0.5 g NaCitrate dibasic sesquihydrate, 1 g NaCitrate tribasic dihydrate	50	55227-U
Supel™ QuE Citrate/Sodium Bicarbonate (EN) Tube – 4 g MgSO4, 5 g NaBicarbonate, 1 g NaCl, 0.5 g NaCitrate dibasic	50	55237-U
Method AOAC 2007.01 (12 mL centrifuge tubes)
Supel™ QuE Acetate (AC) Tube – 6 g MgSO4, 1.5 g NaAcetate	50	55234-U
Non buffered extraction tubes (12 mL centrifuge tubes)
Supel™ QuE Non-Buffered Tube 1 – 4 g MgSO4, 1 g NaCl	50	55294-U
Supel™ QuE Non-Buffered Tube 2 – 6 g MgSO4, 1.5 g NaCl	50	55295-U

Products for Cleanup (QuEChERS) Step

Method – EN15662:2008

Matrices*		Product Description	Cat. No. 2 mL Tubes	Cat. No. 15 mL Tubes
Groups 1, 2 and 3	General fruits and vegetables lightly pigmented	150 mg Supelclean™ PSA, 900 mg MgSO4	—	55437-U
		25 mg Supelclean™ PSA, 150 mg MgSO4	55172-U	—
	Pigmented fruits and Vegetables Moderate levels of chlorophyll and carotenoids	150 mg Supelclean™ PSA, 15 mg Supelclean™ ENVI-Carb™, 900 mg MgSO4	—	55446-U
		25 mg Supelclean™ PSA, 2,5 mg Supelclean™ ENVI-Carb™, 150 mg MgSO4	55147-U	—
	Pigmented fruits and vegetables High levels of chlorophyll and carotenoids	150 mg Supelclean™ PSA, 45 mg Supelclean™ ENVI-Carb™, 900 mg MgSO4	—	55464-U
		25 mg Supelclean™ PSA, 7,5 mg Supelclean™ ENVI-Carb™, 150 mg MgSO4	55176-U	—
Groups 4, 5 and 6	Pigmented fruits and vegetables with waxes/lipids High Lipid Content	150 mg Supelclean™ PSA, 150 mg Discovery® DSC-18, 900 mg MgSO4	—	55439-U
		25 mg Supelclean™ PSA, 25 mg Discovery® DSC-18, 150 mg MgSO4	55173-U	—

Method – AOAC 2007.01

Matrices*		Product Description	Cat. No. 2 mL Tubes	Cat. No. 15 mL Tubes
Groups 1, 2 and 3	General fruits and vegetables lightly pigmented	400 mg Supelclean™ PSA, 1200 mg MgSO4	—	55466-U
		50 mg Supelclean™ PSA, 150 mg MgSO4	55287-U	—
	Pigmented fruits and Vegetables Moderate levels of chlorophyll and carotenoids	50 mg Supelclean™ PSA, 150 mg MgSO4, 50 mg ENVI-Carb™	on request	—
	Pigmented fruits and vegetables High levels of chlorophyll and carotenoids	50 mg Supelclean™ PSA, 150 mg MgSO4, 50 mg Discovery® DSC-18, 50 mg ENVI-Carb™	55289-U	—
		400 mg Supelclean™ PSA, 1200 mg MgSO4, 400 mg Discovery® DSC-18, 400 mg ENVI-Carb™	—	55474-U
Groups 4, 5 and 6	Pigmented fruits and vegetables with waxes/lipids High Lipid Content	50 mg Supelclean™ PSA, 150 mg MgSO4, 50 mg Discovery® DSC-18	55288-U	—
		400 mg Supelclean™ PSA, 1200 mg MgSO4, 400 mg Discovery® DSC-18	—	55470-U

Specialty Products for Method EN15662 or AOAC 2007.01 – Alternatives

Matrices*		Product Description	Cat. No. 2 mL Tubes	Cat. No. 15 mL Tubes
Groups 4, 5 and 6	Fatty or pigmented matrix With less than 15% fat	20 mg Z-Sep, 50 mg Discovery® DSC-C18 (alternative)	55284-U	—
		120 mg Z-Sep, 300 mg C18 (alternative)	—	55506-U
	Hydrophobic analytes in fatty matrices	75 mg Z-Sep (alternative)	55411-U	—
		50 mg Z-Sep, 150 mg MgSO4 (alternative)	55417-U	—
		500 mg Z-Sep (alternative)	—	55491-U
		300 mg Z-Sep, 900 mg MgSO4 (alternative)	—	55503-U
	Fatty matrices With greater than 15% fat	75 mg Z-Sep+ (alternative)	55408-U	—
		50 mg Z-Sep+, 150 mg MgSO4 (alternative)	55414-U	—
		500 mg Z-Sep (alternative)	—	55486-U
		300 mg Z-Sep+, 900 mg MgSO4 (alternative)	—	55511-U
	Improved recovery of planar pesticides in green matrices	Supel™ QuE Verde, 150 mg MgSO4, 10 mg ENVI™-Carb Y, 50 mg PSA, 60 mg Z-Sep+	55447-U	—
		Supel™ QuE Verde, 1200 mg MgSO4, 80 mg ENVI™-Carb Y, 400 mg PSA, 480 mg Z-Sep+	—	55442-U