Welch Materials
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.
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Welchrom QuEChERS

QuEChERS – a Simplified Method of Sample Preparation for Pesticide Analysis

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.


Why Welchrom® QuEChERS?

• Saving time and money for your sample preparation

• High quality, best reproducibility

• Lowest contamination

• Lower cost as compared to other brands

 

How QuEChERS works?

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.


Welchrom® QuEChERS Workflow

Step 1: Extraction

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

 

Welchrom® QuEChERS Extraction Kits:

 

• 50ml tubes

• Pre-packaged MgSO4, NaCl or other salts

 

Welchrom® QuEChERS Extraction Bags Ordering Information (without 50ml tubes)


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

Step 2: Clean up


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.

 

Welchrom® QuEChERS Clean-up Tubes Ordering Information

 

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

 

What are these sorbents used for?

 

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

Bulk Sorbents



the Clean-up result from Spinage using different content of Welchrom® GraphiCarb



Application: the analysis of multi-residue pesticide in apple using Welchrom QuEChERS Kit

Extraction

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

Clean up

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

GC Method

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

Mass Method

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



Results



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