QuEChERS Sample Prep and its Cleanup Effectiveness and

Efficiency – A Look at Sorbents

QuEChERS1. 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 interferentswith C18 Silica

2. Dispersive Solid Phase Extraction (dSPE) Cleanup of Interferents

O

OH

O

OHH3C

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 dSPEcleanup with GCB

Spiked spinach QuEChERS extracts (at 625 ng/mL)w/o GCB clean‐up (5 μL PTV injections)

Not OK after100 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 (%)

N

N

ClCl

Cl

Cl

N

O

O

S

C

Cl

Cl Cl

Current Solution – GCB

A New Engineered Carbon Material

CarbonX GCB Before AfterAfter

Effect of Glass Microscope Slide Weight on Particle Diameter

Intact particlesafter grinding

Crushed Particles

Pore Diameter (A)

Pore

Vol

(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

Carb

onX

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 GCBGCB 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

Dic

hlor

vos

Phen

ylPh

enol

Lind

ane

Dia

zino

n

Chl

orot

halo

nil

Chl

orpy

rifos

-met

hyl

Dic

hlor

oben

zoph

enon

e

Chl

orpy

rifos

Hep

tach

lorE

poxi

de

Folp

et

Gam

maC

hlor

dane

Alph

aChl

orda

ne

Die

ldrin

DD

E

Ethi

on

Endo

sulfa

nSul

fate

Perm

ethr

ine

Cou

map

hos

Rec

over

y (%

)

CarbonX PlusGCBGCB 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

0 5 10 15 20 25 30 35 40 45 50

Injection Number

Ave

rage

Rec

over

y of

Pes

ticid

es (N

orm

aliz

ed to

Initi

al R

ecov

erie

s)

GCBCarbonX 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

120.0Dichlorvos

Phen

ylph

enol

Atrazine

Lind

ane

Diazino

n

Chlorothalon

il

Chlorpyrifo

s‐methyl

DCB

P

Chlorpyrifo

s

Hep

techlor Ep

oxide

Folpet

γ chlordane

α chlordane

Dieldrin

DDE

Ethion

Endo

sulfa

n Sulfa

te

Perm

ethrin

Coum

apho

s

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

Dic

hlor

vos

Phen

ylph

enol

Atr

azin

e*

Lind

ane

Dia

zino

n

Chl

orot

halo

nil

Chl

orpy

rifos

-met

hyl

DC

BP

Chl

orpy

rifos

Hep

tech

lor E

poxi

de

Folp

et

γ ch

lord

ane

α ch

lord

ane

Die

ldrin

DD

E

Ethi

on

Endo

sulfa

n Su

lfate

Perm

ethr

in

Cou

map

hos

Rec

over

y (%

)

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 ThompsonUnited Science

Dr. Chunze LaiR&D

Dr. Li ChenR&D

Dr. Conor SmithR&D

Prof. Dwight StollGustavus

Doug FryerProduct Manager