1. The document discusses QuEChERS sample preparation and cleanup methods using different sorbents to remove interferents like fatty acids, pigments, and sterols from pesticide extracts. 2. It evaluates the effectiveness of a new engineered carbon material called CarbonX compared to traditional glass-backed carbon sorbent for removing contaminants while maintaining high pesticide recoveries and minimizing column and liner fouling during GC/MS analysis. 3. The CarbonX material showed superior recoveries of planar pesticides above 75% and was able to remove extreme fatty acid contaminants from botanical extracts, demonstrating its potential to handle difficult sample matrices compared to other cleanup methods.

1. QuEChERS Sample Prep and its
Cleanup Effectiveness and
Efficiency – A Look at Sorbents

2. QuEChERS
1. Extraction of Pesticides With Acetonitrile, MgSO4 and Salt
Cleanup of Fatty Acids with
Primary Secondary Amine
Cleanup of
Pigments with
GCB
Cleanup of Sterols and
Non-polar interferents
with C18 Silica
2. Dispersive Solid Phase Extraction (dSPE) Cleanup of Interferents
O
OH
O
OHH3C
H3C
Palmitic Acid
Stearic Acid
Chlorophyll a
Campesterol

3. Pigmented Sample Issues
• Liner Fouling
• Column Retention Time
Shortens
• Peak Tailing
Carrot Pea Pineapple Raspberry
Liner with 50
Injections of
Spinach Extract
after dSPE
cleanup with
GCB

4. Spiked spinach QuEChERS extracts (at 625 ng/mL)
w/o GCB clean‐up (5 μL PTV injections)
Not OK after
100 injections
Slide from Steven Lehotay, USDA-ARS

5. 0.0 20.0 40.0 60.0 80.0 100.0 120.0
Chlorothalonil
Chlorpyrifos-methyl
DCBP
Chlorpyrifos
Folpet
Coumaphos
Recovery (%)
N
N
ClCl
Cl
Cl
N
O
O
S
C
Cl
Cl Cl
Current Solution – GCB

6. A New Engineered Carbon Material
CarbonX GCB
Before AfterAfter
Effect of Glass Microscope Slide
Weight on Particle Diameter
Intact particles
after grinding
Crushed Particles
Pore Diameter (A)
PoreVol(cm3/g)
Repeatable and Reproducible Pore Structure
80 A avg pore
0
0.2
0.4
0.6
0.8
1
1.2
0 100 200 300 400
CarbonX
GCBSPE1
Time(min)
Time to elute 4 mL of
CH2Cl2 from
3 mL SPE Cartridge
under gravity flow.
N= 10. GCB cartridge
is commercially
packed & sourced.
More Reproducible Flow Characteristics
100 um

7. Color results from 3 cleanup styles
GCBGCB w/ Tol
CarbonX
Plus
Spinach
Extract

8. Recoveries from 3 cleanup styles
0.0
20.0
40.0
60.0
80.0
100.0
120.0
140.0
160.0
Dichlorvos
PhenylPhenol
Lindane
Diazinon
Chlorothalonil
Chlorpyrifos-methyl
Dichlorobenzophenone
Chlorpyrifos
HeptachlorEpoxide
Folpet
GammaChlordane
AlphaChlordane
Dieldrin
DDE
Ethion
EndosulfanSulfate
Permethrine
Coumaphos
Recovery(%)
CarbonX Plus
GCB
GCB Toluene

9. Cleanup Style Affects SIM Baseline
CarbonX Plus
GCB
GCB w/Tol

10. Cleanup Efficiency – X and Y axis
88
90
92
94
96
98
100
102
0 5 10 15 20 25 30 35 40 45 50
Injection Number
AverageRecoveryofPesticides(NormalizedtoInitialRecoveries)
GCB
CarbonX Plus

11. Powdered Botanicals - Extreme
Fatty Acid Cleanup
Saw Palmetto Uncleaned
Saw Palmetto 450 mg PSA added to AOAC
Pigmented dSPE Tube

12. Powdered Botanicals - Extreme
Fatty Acid Cleanup
Ginkgo Biloba Uncleaned
Ginkgo Biloba 250 mg PSA added to AOAC
Pigmented dSPE Tube

13. Good Recoveries After Cleanup
0.0
20.0
40.0
60.0
80.0
100.0
120.0 Dichlorvos
Phenylphenol
Atrazine
Lindane
Diazinon
Chlorothalonil
Chlorpyrifos‐methyl
DCBP
Chlorpyrifos
Heptechlor Epoxide
Folpet
γ chlordane
α chlordane
Dieldrin
DDE
Ethion
Endosulfan Sulfate
Permethrin
Coumaphos
Recovery (%)
Ginkgo Biloba
Saw Palmetto

14. Miniaturize and Automate - ITSP
0.0
20.0
40.0
60.0
80.0
100.0
120.0
140.0
Dichlorvos
Phenylphenol
Atrazine*
Lindane
Diazinon
Chlorothalonil
Chlorpyrifos-methyl
DCBP
Chlorpyrifos
HeptechlorEpoxide
Folpet
γchlordane
αchlordane
Dieldrin
DDE
Ethion
EndosulfanSulfate
Permethrin
Coumaphos
Recovery(%)
1. Condition with 100 µL 1% Acetic Acid ACN
2. Inject 100 µL of Sample Extract
3. Elute with 100 µL 1% Acetic Acid ACN

15. Conclusions
• Superior QuEChERS Recoveries with
Engineered Carbon for GC/MS
• Similar Color Removal
• Greater than 75% recovery for planar pesiticides
• Toluene Unnecessary
• Decreased Liner and Column Fouling
• Sometimes Extreme Issues Can Necessitate
Extreme Cleanup Solutions
• Miniaturization Can Assist when Sample Volume
is an Issue or Automation is Desired
Confidential

16. Dr. Jon Thompson
United Science
Dr. Chunze Lai
R&D
Dr. Li Chen
R&D
Dr. Conor Smith
R&D
Prof. Dwight Stoll
Gustavus
Doug Fryer
Product Manager