QuEChERS Sample Prep and its Cleanup Effectiveness and Efficiency - - PowerPoint PPT Presentation

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

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 OH H3C H3C

Palmitic Acid Stearic Acid Chlorophyll a Campesterol

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

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

0.0 20.0 40.0 60.0 80.0 100.0 120.0 Chlorothalonil Chlorpyrifos-methyl DCBP Chlorpyrifos Folpet Coumaphos

Recovery (%)

Current Solution – GCB

A New Engineered Carbon Material

CarbonX GCB Before After After

Effect of Glass Microscope Slide Weight on Particle Diameter

Intact particles after grinding Crushed Particles

Pore Diameter (A) Pore Vol (cm3/g) Repeatable and Reproducible Pore Structure

80 A avg pore

0.2 0.4 0.6 0.8 1 1.2 100 200 300 400

CarbonX GCB SPE1 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

Color results from 3 cleanup styles

GCB GCB w/ Tol CarbonX Plus Spinach Extract

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

Cleanup Style Affects SIM Baseline

CarbonX Plus GCB GCB w/Tol

Cleanup Efficiency – X and Y axis

88 90 92 94 96 98 100 102 5 10 15 20 25 30 35 40 45 50

Injection Number Average Recovery of Pesticides (Normalized to Initial Recoveries)

GCB CarbonX Plus

Powdered Botanicals - Extreme Fatty Acid Cleanup

Saw Palmetto Uncleaned Saw Palmetto 450 mg PSA added to AOAC Pigmented dSPE Tube

Powdered Botanicals - Extreme Fatty Acid Cleanup

Ginkgo Biloba Uncleaned Ginkgo Biloba 250 mg PSA added to AOAC Pigmented dSPE Tube

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

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 Heptechlor Epoxide Folpet γ chlordane α chlordane Dieldrin DDE Ethion Endosulfan Sulfate 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

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

• 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