Welch Materials develops and manufactures Chromatography consumables including HPLC columns, Solid Phase Extraction (SPE) columns, GC columns, sample vials, syringe filters, and chromatographic media.

Welch Materials was established in 2003 in both Maryland, USA and Shanghai, China. We are experts on bonding chemistry and innovative packing materials for chromatography applications. Through the optimal utilization of our resources across the two countries, we have developed many innovative chromatographic consumable products, including HPLC columns, SPE products and QuEChERS. UltisilTM, Welchrom®, XtimateTM and TopsilTM are registered trademarks of Welch Materials. Over the past several years, these high quality products have become widely accepted by analytical chemists in many countries, especially in China, US, and Europe.

In 2003, M Anastassisdes developed a simple way to prepare food samples for pesticide analysis. It’s called QuEChERS (pronounced as “Catchers”), an acronym for Quick, Easy, Cheap, Effective, Rugged and Safe. With QuEChERS, you could prepare your samples in multi-class, multi-residue pesticide analysis while saving time and money. Welch Materials provides high quality, competitive price Welchrom® QuEChERS for your sample preparation.

• Saving time and money for your sample preparation

• High quality, best reproducibility

• Lowest contamination

• Lower cost as compared to other brands

 

QuEChERS extraction method is designed for multi-residue pesticide analysis of fruits and vegetables with high water content (80%-95%). Some compounds will interfere the detection of target pesticide, such as chlorophyll, fatty acid, pigment, which could be removed by QuEChERS.

Some QuEChERS methods add buffers during the extraction step. Two most common methods are the European Committee for Standardization (CEN 15662) method which applies citrate buffer for extraction and the Association of Analytical Communities (AOAC 2007.01) method using acetic acid buffer.
For low-water content fruits and vegetables, additional water needs to be added to optimize the extraction. For high-fatty content fruits and vegetables, C18E should be added to remove it. For high-pigment content fruits and vegetables, graphicarb should be added.

Transfer homogenized sample (10g or 15g) to 50ml tube, then add extraction solvent and salt, shake for one minute, centrifuge > 1500rcf for 1 minute.

 

 

• 50ml tubes

• Pre-packaged MgSO4, NaCl or other salts

 

	Part Numbers	Pack Size	MgSO	Na Acetate	Na Citrate	Na Citrate Sesquihtdrate	NaCl
AOAC QuEChERS Extraction Bags for 15 g samples	00528-00000	100	6 g	1.5 g
EN uEChER SExtraction Bags for 10 g Samples	00529-00000	100	4 g		1 g	0.5 g	1 g
Original QuEChERS Extraction Bags 10 g Samples	00530-00000	100	4g				1 g

Choose right clean up tube, transfer the extracted sample in Step 1 to clean up tube, shake for 30 seconds, then centrifuge > 1500 rcf for 1 minute.

 

	Part Numbers	Tubes	Pack Size	MgSO4	PSA	C18E	GCB
AOAC Methodfruits and vegetables	00531-20020	2 mL	100	150 mg	50 mg	-	-
	00531-20021	15 mL	50	1200 mg	400 mg
EN Method fruits and vegetables	00532-20020	2 mL	100	150 mg>	25 mg	-	-
	00532-20021	15 mL	50	900 mg	150 mg
AOAC Method Waxy or fatty fruits and vegetables	00533-20020<	2 mL	100	150 mg	50 mg	50 mg	-
	00533-20021	15 mL	50	1200 mg	400 mg	400 mg
EN Method Waxy or fatty fruits and vegetables	00534-20020	2 mL	100	150 mg	25 mg	25 mg	-
	00534-20021	15 mL	50	900 mg	150 mg	150 mg	-
AOAC Method Pigment content fruits and vegetables	00535-20020	2 mL	100	150 mg	50 mg	-	50 mg
	00535-20021	2 mL	50	1200 mg	400 mg	-	400 mg
EN Method Pigment content fruits and vegetables	00536-20020	2 mL	100	150 mg	25 mg	-	2.5 mg
	00536-20021	15 mL	50	900 mg	150 mg	-	15 mg
AOAC Method High pigment and fatty content fruits and vegetables	00537-20020	2 mL	100	150 mg	50 mg	50 mg	50 mg
	00537-20021	15 mL	50	1200 mg	400 mg	400 mg	400 mg
EN Method High pigment content fruits and vegetables	00538-20020	2 mL	100	150 mg	25 mg		7.5 mg
	00538-20021	15 mL	100	900 mg	150 mg		45 mg

 

MgSO1	Remove H2O in the matrix
PSA	Adsorb the carbohydrate, fatty acid, organic acid and some pigment in the matrix
C18E	Remove non-polar compounds in the matrix
GCB	Remove pigment, sterol in the matrix

1) Transfer homogenized sample (10g or 15g) to 50ml tube
2) Add 15ml CAN with 1% HOAC
3) Add internal standard
4) Shake for 1 min
5) Add 00529-00000 extraction salt into tube
6) Shake for 1 min
7) Centrifuge > 4000rpm for 5 min
8) Get the above liquid


1) Add 1 ml above liquid sample into 00531-20020 clean up tube, shake for 1 min
2) Add 8 ml above liquid sample into 00532-20021 clean up tube, shake for 1 min
3) Centrifuge > 13000rpm for 2 min
4) Get the above liquid for injection


Autosampler: Agilent 7683 AS
Column: Welchrom WM-5MS GC Column,30 m*0.25 mm, 0.25um
Gas: He
Temp: 70ć(2min),25ć/min to 150ć(0min),3ć/min to 200ć(0min),8ć/min to 280ć
Volume: 1.0ul


Mode: SIM
Source: Quadrupole Interface
Temp: 230ć, 150ć and 280ć

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