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What you don’t see… …CAN hurt you Sample Prep for Today’s Analytical World Christophe Deckers, M.Sc. Application Scientist, Sample Prep [email protected]
What you don’t see…
…CAN hurt you
Sample Prep for Today’s Analytical World
Christophe Deckers, M.Sc.Application Scientist, Sample Prep
Today’s Agenda
IntroductionAddressing difficult samples1. Polar analytes2. High fat samples3. How to get rid of interfering terpenesSummary and Conclusions
NACRW 2015
1March 17
Objectives of Sample Preparation
• Removal of interferences which would affect detection of analyte
• Removal of interferences that would affect instrument or column lifetime
• Concentration of an analyte to a detectable concentration
With news instruments - more Sample Preparation Techniques can be used
4
More Specific ← Instrument Separation and Detection Specificity ← Less Specific
Less Specific → Sample Preparation Specificity → More Specific
Sample Prep Technique
Interference Removed
Dilute & Shoot Filtration Liquid/Liquid Extractions
Supported Liquid Extractions (SLE)
Dried Matrix Spotting Precipitation QuEChERS
Lipid Removal ‘Hybrid'
Filtration
Solid Phase Extraction
Lipids No No No Some No No Yes Yes Yes
Oligomeric Surfactants No No No No No No No Yes Yes
Particulates No Yes No Some No Yes Yes Yes Yes
Pigments No No No Some No No Yes No Yes
Polar Organic Acids No No Yes Yes No No Yes No
Proteins No No Yes Yes Yes Yes Yes Yes Yes
Salts No No Yes Yes No No No No Yes
Suggested Agilent Product
Agilent Autosampler
Vials
Captiva Syringe Filters Chem Elut Captiva ND Bond Elut
QuEChERS Captiva ND LIPIDSBond Elut Silica and Polymeric
SPE
Agilent Captiva Filtration Products are recommended for use with any LC or LC-MS method
Today’s Agenda
IntroductionAddressing difficult samples1. Polar analytes2. High fat samples3. How to get rid of interfering terpenesSummary and Conclusions
NACRW 2015
1March 17
Polar analytes often require advanced solid phase extraction (SPE)
- Analyte is too polar for acetonitrile extraction- Filtration is not clean enough- Ion exchange can be used to filter polar interferences away- We then often need an SPE phase that can bind a wide range of polar analytes that are basic, neutral and acidic
March 17
NACRW 2015
6
Bond Elut Packed Bed Phases – Which one!Non-polar
C18, C8, C2, C1C18 variations in carbon load and endcappingEnvirElutCH – cyclohexylCN-E – endcapped cyanoPH – phenylENV, LMS, PPL, Focus, Bond Elut Plexa
PolarPSA - primary and
secondary amineNH2 - aminopropylCN-U –unendcapped cyanoDEA - diethylaminopropylDiolSi - silica
Cation ExchangeSCX – benzenesulfonic acidPRS – propylsulfonic acidCBA – carboxylic acid
Anion ExchangeSAX – quaternary aminePSA – primary and
secondary amineNH2 – aminopropylDEA – diethylaminopropyl
Mixed mode IEX/NPCertify – SCX/C8Certify II – SAX/C8Plexa PCXPlexa PAX
Reversible CovalentPBA – phenylboronic acid
Alumina – aluminum oxideFlorisil – magnesium-silicaCarbonCarbon/NH2
Nexus
Specialty PhasesAccuCATAtrazineEtc..
Bond Elut Plexa - A Different Type of Polymeric Sorbent
Polar and non polar drugs bind in the SDVB hydrophobic end of the pore structure
• The hydroxylated ligands exist on the surface and in the outer regions of the pores. • Deep inside the pore is pure S/DVB. • There is no amide functionality (N-vinylpyrolidone) which might contribute to retaining matrix interferences
March 6, 2017Confidentiality Label
Plexa Recoveries Versus HLB – good results with a wide range of compounds
Analyte Plexa HLB pKa LogPAlbuterol 97.9 115.4 5.9 1.3
Atenolol 97.0 94.0 4.2 4.2
Loratadine 71.0 49.0 5.7 1.5
Metoprolol 92.0 74.0 5.7 1.5
Naltrexone 85.7 13.0 4.9 5.2
Pravastatin 85.0 59.0 4.9 5.2
Propranolol 55.0 35.0 4.9 5.2
Zolpidem 93.0 96.8 9.9 3.4
Plexa gives equivalent or better absolute recoveries than Oasis HLB for a wide range of pKa and logP compoundsConditions: Absolute Recovery from human plasma Basic load conditions, n=6, 200 ng/ml
Hydrophobic/ hydrophilic boundary
Sorbent Conditioning - Why Do It?
10
11
Drying a silica-based Cartridge (ex: C18)
Over drying / lack of conditioning before sample application can contribute to
• low recoveries• poor flow• irreproducibility (high RSDs)
Examples on how polymeric SPE perform
March 6, 2017Agilent Confidential
12
Bond Elut Plexa / Phenols from Drinking Water
Bond Elut PPL - EPA 528 Phenols from Drinking Water
Method 528 provides procedures for the determination of phenols in finished drinking water. The method may be applicable to untreated source waters but has not been evaluated for these uses. The method is applicable to a variety of phenols that are efficiently partitioned from the water sample into a modified PSDB SPE sorbent (Varian’s PPL) and is sufficiently volatile and thermally stable for gas chromatography.
Extraction is performed by passing a 1L water sample through a SPE cartridge with 500mg modified PSDB (PPL). The phenols are eluted with methylene chloride.
Determination of Organophosphates in Lake Water: Bond Elut PPL SI-02094Julia Regnery, Goethe-Universität Frankfurt, Institut für Atmosphäre und Umwelt, AG-Umweltanalytik, 60438 Frankfurt, Germany, Elisabeth Korte, Varian Deutschland GmbH
15
Chlorinated organophosphates are used as flame retardants in insulation foams, paints, coatings, plastics, and textiles while the non-chlorinated ones are mostly used as plasticizers. The compounds have been detected in air, sediment and soil, sewage sludge, streams and lakes. Particularly the chlorinated organophosphates are known to persist in the aquatic environment.
• Because of the low concentration of the analytes in the water sample an enrichment step is necessary.
16
Cartridge: Bond Elut PPL, 100 mg sorbent in 1 mL cartridge
Condition: 1 mL methanol, 1 mL methanol / acetonitrile (1/1)
Apply 1.5 -2.5 L water sample
Dry the cartridge using nitrogen
Elution with 3 x 333 µL methanol / acetonitrile (1/1)
SPE Conditions
Results
17
The simple clean-up and enrichment with SPE has the advantage that up to 20 water samples can be extracted simultaneously without using complex apparatus. Bond Elut PPL has been proven to be a robust sorbent with high capacity for the extraction of polar and medium polar analytes.
Conclusion
Novel polymeric SPE phases are recommended:
1. They have double the binding capacity over silica2. They can bind a wide range of polar analytes3. They don’t decondition/dry out on the SPE manifold4. They provide more robust methods
March 6, 2017Confidentiality Label
18
Today’s Agenda
Introduction
Addressing difficult samples
1. Polar analytes
2. High fat samples3. How to get rid of interfering terpenes
Summary and Conclusions
NACRW 2015
1
March 17
Remove interferences…
• To acquire desired sensitivity/selectivity• To reduce contamination/carryover issues• Use of sensitive and expensive instruments: Protect your
investment!!!
Pesticides in Avocado with SPPesticides in Avocado without SP
March 17
NACRW 2015
20
Lipids
March 17
NACRW 2015
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Matrices and Approximate Total Lipid Content<2% 4-12% >12%
Beef Liver (4%)
Canola Oil (100%)
Nut Butters (16%)Spinach (0%)Strawberry (0%)
Onion (0%)
Canned Pet Food (~10%)
Avocado (21%)
Chocolate (8%)
Soy Milk (4%)
Pork Liver (4%)
Soy Oil (100%)Avocado Oil (100%)
Coconut Oil (100%)
Paprika (1%)
Hops (2%)
Cumin (2%)
Salmon (27%)Corn (4%)
Rice (2%)
Wheat (3%)
Catfish (12%)
Sea Bass (3%)
Carp (12%)
Trout (8%)
Tilapia (2%)
Pork (8%)
Plasma or whole blood(10 – 20 %)
Cow’s Milk (5%)
Low Med High
March 17
NACRW 2015
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Current Procedures for Lipid Removal
Method How Lipids are removed Weakness
Dilute and Shoot No lipid removal, only dilution No lipid removal
Protein Precipitation PPT followed by centrifugation Insufficient lipid removal
PPT followed by filtration with or without sorbent
Insufficient lipid removal; low analyterecovery
QuEChERS PSA/C18 sorbent (dSPE) Not selective; insufficient lipid removal; analyte loss
Zr-containing sorbent Low total lipid capacity; analyte recovery
Freeze sample Time needed; loss of analyte
SPE/SLE Load and elute Time needed; solvent usage; extensive method development
SEC/GPC Chromatographic separation Uses copious amounts of solvent and time; capital expense
March 17
NACRW 2015
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EMR-Lipid Enhanced Matrix Removal
EMR: As easy to use as QuEChERS; as clean as SPE
March 17
NACRW 2015
24
EMR fits into current sample preparation workflows
EMR-Lipid (p/n 5982-1010)
EMR-Polish (p/n 5982-0102)Extraction Tube
EMR Product offering
March 17
NACRW 2015
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EMR Sorbent - What is it?
When “activated” by water… - The materials selective
hydrophobic interactions increase.
- Suspension of nano particles (high surface area).
- Rapidly interacts with straight chain, “lipid-like” functional groups.
Centrifugation preferably used to separate precipitate from solution (not filtration).
EMR-Lipid Mechanism – Size exclusion and hydrophobic interaction.
March 17
NACRW 2015
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1.0 g EMR in 15 mL tube
… and what does it do?
EMR sorbent removes LipidsWhat are Lipids?
A class of naturally occurring hydrocarbon containing compounds commonly known as fats and oils
Free Fatty Acids
Triglycerides
Cholesterol Phospholipids
March 17
NACRW 2015
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What Does EMR NOT Interact With?
EMR does NOT remove analytes of interestExceptions?
Compounds containing long aliphatic functional groups (e.g. prostaglandins)
Fluoroquinolones Tetracyclines
Vitamin DPAHsOrganochlorine Pesticides
Imidazole pesticides
March 17
NACRW 2015
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EMR Fits into Existing Workflows
QuEChERS (Quick, Easy, Cheap, Effective, Rugged, Safe)• Easy-to-use sample preparation for food testing, solid
samples (e.g. vegetables, fruits, meat, seafood, etc.)EMR Applications: - Pesticide Residues in Avocado,
Modified Liquid Extraction (Protein Precipitation)• Proteins are removed by a “crash” step prior to injection
or cleanup (e.g. milk, meat, seafood, etc.)EMR Applications: - PAHs in Salmon,
- Veterinary Drugs in Bovine Liver
March 17
NACRW 2015
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Pros• Fast and inexpensive• Takes minimal experience• Doesn’t require special equipment• Accommodates multiple matrices• Accommodates large analyte groupsCons• Large amount of coextractives
Improving dSPE in QuEChERS1. Extraction 2. Dispersive SPE
Pros• Same as extractionCons• Minimal cleanup provided• Can remove analytes• Lipids are challenging to remove
selectively
March 17
NACRW 2015
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EMR – Lipid – dSPE Cleanup
A B C D
E
A. QuEChERS or Liquid ExtractB. Add H2O to EMR tube (“activation”)C. Transfer extractD. Vortex and centrifugeE. Supernatant (1:1; extract: H2O)
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NACRW 2015
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EMR – Polish – ACN/H2O Phase Separation
A B C D
E
A. Add supernatant to EMR – Polish tubeB. Vortex immediatelyC. Phase separation after centrifugeD. Transfer upper layer for analysisE. Final samples split for GC and LC analysisF. Extra dry step recommended prior to GC
March 17
NACRW 2015
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EMR Workflow
Extract dSPE Polish Dry
In acetonitrileOr acetone
3/6/2017
33
GC-MS Fullscan Avocado
Avocado – Untreated
March 17
NACRW 2015
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GC-MS Fullscan Avocado
Avocado – UntreatedAvocado – EMR Treated
March 17
NACRW 2015
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GC-MS Fullscan Pet Food
Pet Food – Untreated
March 17
NACRW 2015
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GC-MS Fullscan Pet Food
Pet Food – UntreatedPet Food – EMR Treated
March 17
NACRW 2015
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GC-MS Full Scan– Avocado Oil
Avocado Oil ExtractEMR – Lipid Extract
March 17
NACRW 2015
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GC-MS Spinach Fullscan
March 17
NACRW 2015
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Spinach matrix blank w/ EMR cleanup
Spinach matrix blank w/o cleanup
Spinach matrix blank w/ Q-Pigment dSPE cleanup
Spinach matrix blank w/ Q-Universal dSPE cleanup
5.00 10.00 15.00 20.00 25.00 30.00 35.000
500000
1000000
1500000
2000000
2500000
3000000
3500000
4000000
4500000
5000000
Time-->
Abundance
GC-MS Red Pepper Fullscan
March 17
NACRW 2015
40
5.00 10.00 15.00 20.00 25.00 30.00 35.000
500000
1000000
1500000
2000000
2500000
3000000
3500000
4000000
4500000
5000000
5500000
Red Pepper matrix blank w/ EMR cleanup
Red Pepper matrix blank w/o cleanup
Red Pepper matrix blank w/ Q-General dSPE cleanup
Red Pepper matrix blank w/ Q-Universal dSPE cleanup
Benefits to Instrumental Flowpath
March 17
NACRW 2015
41
Comparison of Analytes Response Consistency over Multiple Avocado Sample Injections
TPP
Commonly used IS
RT: 18.3 min
0
2000
4000
6000
8000
10000
12000
14000
16000
18000
20000
5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100
TPP
Peak
Are
a
Injections of Avocado Samples on GC-QQQ
TPP Peak Area over 100 Injections
EMR cleanup
Z-Sep+ cleanup
C18 dSPE cleanup
Linear (EMR cleanup)
Linear (Z-Sep+ cleanup)
Linear (C18 dSPE cleanup)
Response drops ~ 50% after 100 avocado sample injections
Response increases ~ 35% after 100 avocado sample injections
Response drops ~ 4% after 100 avocado sample injections
March 17
NACRW 2015
42
Analytes Responses Reproducibility on GC/MS/MS over 100 Injections of Avocado Samples
March 17
NACRW 2015
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MS Source Critical Tuning Parameters
0
200
400
600
800
1000
1200
1400
1600
0
10
20
30
40
50
60
70
80
90
100
110
120
130
0 500 1000 1500 2000 2500
EM V
olat
age
Rela
tive
Abun
danc
e fo
r Tun
ing
Ion
(%)
Injections of Avocado Samples with EMR cleanup on GC/MS
MS (GC/MS) Performance Monitoring over Multiple Avocado Sample Injections
Rel Abundance for Ion 219, Minimum of 70 needed
Rel Abundance for Ion 502, minimum of 5 needed
EM voltage, higher than 1400 indicated needs to replace
March 17
NACRW 2015
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67 Pesticides Analysis in Avocado by LC and GC-QQQ
March 17
NACRW 2015
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Accurately weigh 15 g comminuted Avocado sample in 50 mL centrifuge tube
Centrifuge @ 5000 rpm for 5 min
Transfer 5 mL of upper ACN extract and 5 mL of water to EMR dSPE 15 mL tubes
Add 15 mL of 1% Acetic Acid in Acetonitrile, and AOAC QuEChERS extraction kit
Cap and shake vigorously on mechanical shaker for 2 min
Vortex and Centrifuge
QuEChERS-EMR Protocol for Multi-residue Analysis of Pesticides in Avocado
Combine 200 µL of ACN extract and 800 µL water, vortex, and centrifuge if needed
Transfer 5 mL supernatant to empty tube, add content of Polish Pouch
Vortex, centrifuge, and transfer the upper ACN layer to another vial
Samples are ready for GC-QQQ analysis after dry step Samples are ready for LC-QQQ analysis
March 17
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CleanupAmount of co-
extractives(mg, n= 3)
Amount of co-extractives removed by
cleanup (mg, n = 3)
% of matrix co-extractives removed by
cleanup
No further cleanup 14.7 --
C18/PSA Cleanup 9.5 5.2 35.4
EMR-Lipid Cleanup 4.2 10.5 71.4
Zirconia sorbent Cleanup 7.0 7.7 52.4
% Matrix Co-extractives Removed by Cleanup = 𝐴𝐴𝐴𝐴𝐴𝐴𝐴𝐴𝐴𝐴𝐴𝐴 𝐴𝐴𝑜𝑜 𝐶𝐶𝐴𝐴−𝑒𝑒𝑒𝑒𝐴𝐴𝑒𝑒𝑒𝑒𝑒𝑒𝐴𝐴𝑒𝑒𝑒𝑒𝑒𝑒𝑒𝑒 𝑅𝑅𝑒𝑒𝐴𝐴𝐴𝐴𝑒𝑒𝑒𝑒𝑅𝑅 𝑒𝑒𝑜𝑜𝐴𝐴𝑒𝑒𝑒𝑒 𝐶𝐶𝐶𝐶𝑒𝑒𝑒𝑒𝐴𝐴𝐴𝐴𝐶𝐶𝐴𝐴𝐴𝐴𝐴𝐴𝐴𝐴𝐴𝐴𝐴𝐴 𝐴𝐴𝑜𝑜 𝐶𝐶𝐴𝐴−𝑒𝑒𝑒𝑒𝐴𝐴𝑒𝑒𝑒𝑒𝑒𝑒𝐴𝐴𝑒𝑒𝑒𝑒𝑒𝑒𝑒𝑒 𝑤𝑤𝑒𝑒𝐴𝐴𝑤𝐴𝐴𝐴𝐴𝐴𝐴 𝐶𝐶𝐶𝐶𝑒𝑒𝑒𝑒𝐴𝐴𝐴𝐴𝐶𝐶
× 100%
The use of EMR material cleanup removes extra 20-30% of Avocado co-extractives in comparison to traditional QuEChERS and/or competitor’s cleanup
Comparison of Avocado Co-extractives by Weight
March 17
NACRW 2015
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Comparison of GC/MS Full-scan Chromatogram for Matrix Background
The use of EMR material cleanup provides significantly cleanup chromatographic sample background.
March 17
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Comparison of GC/MS/MS MRM Chromatogram for Matrix Background
March 17
NACRW 2015
49
6x10
0
0.5
1
1.5
2
2.5
3
3.5
4
4.5
5
5.5
6
Counts vs. Acquisition Time (min)3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24
6x10
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1
Matrix blank w/ C18/PSA cleanup
Matrix blank w/ zirconia sorbent cleanup
Matrix blank w/ EMR cleanup
Chromatographic Benefits of Matrix Removal Provided by EMR Cleanup
ExampleEPN in Avocado on LC-QQQ
+ MRM (151.0 -> 79.1) AV MBPI-a-CD C2 spike 50ppb-1.D
Acquisition Time (m
12.7 12.8 12.9 13 13.1 13.2 13.3 13.4 13.5 13.6
Coun
ts 4x10
-0.2
0
0.2
0.4
0.6
0.8
1
1.2
1.4
1.6
1.8
2
2.2
2.4
2.6
13.163 min.
+ MRM (151.0 -> 79.1) AV Z-Sep+ C5 spike 50ppb-1.D
Acquisition Time (m
12.7 12.8 12.9 13 13.1 13.2 13.3 13.4 13.5 13.6
Coun
ts 5x10
-0.1
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1
1.1
1.2
1.3
1.4
1.5
1.6
13.163 min.
+ MRM (183.1 -> 168.1) AV MBPI-a-CD C2 spike 50ppb-1.D
Acquisition Time (m
20.4 20.5 20.6 20.7 20.8 20.9 21 21.1 21.2
Coun
ts 4x10
-0.25
0
0.25
0.5
0.75
1
1.25
1.5
1.75
2
2.25
2.5
2.75
3
3.25
3.5
3.75
4
4.25
4.5
4.75
520.788 min.
+ MRM (183.1 -> 168.1) AV Fatty dSPE spike 50ppb-1R.D
Acquisition Time (m
20.4 20.5 20.6 20.7 20.8 20.9 21 21.1 21.2
Coun
ts 4x10
0
0.5
1
1.5
2
2.5
3
3.5
4
4.5
5
5.5
6
6.5
20.833 min.
+ MRM (183.1 -> 168.1) AV Z-Sep+ C5 spike 50ppb-1.D
Acquisition Time (m
20.4 20.5 20.6 20.7 20.8 20.9 21 21.1 21.2
Coun
ts 4x10
0
0.5
1
1.5
2
2.5
3
3.5
4
4.5
5
5.5
6
6.5
20.819 min.
Captan in Avocado on GC-QQQ
Permethrin in Avocado on GC-QQQ
EMR-Lipidcleanup
Zirconia sorbent cleanup
C18/PSAcleanup
Benefit Reduced matrix suppression Improved S/N ratio Less interferences for
accurate integration
March 17
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Selected Problematic Pesticides for Recovery Comparison
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■ Zirconia cleanup
0
20
40
60
80
100
120
Methamidophos Thiophanatemethyl
Bentazone 2,4-D Acid Dichlorprop Penconazole TPP EPN Captafol
Anal
ytes
Rec
over
y %
(n=6
) in
50pp
b pe
stic
ides
fort
ified
Avo
cado
sam
ples
Selected Pesticides Recovery Comparison from Multi-residue Pesticides Analysis in Avocado by LC/QQQ or GC/QQQ
EMR cleanup C18/PSA cleanup Zirconia sorbent cleanup
Statistical Recovery Results Comparison
March 17
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Page 52
Method Accuracy and Precision
March 17
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53
Summary and Conclusion
• EMR-Lipid provides the most complete lipid removal of any sorbent on the market.
• Achieve SPE cleanliness with dSPE simplicity.• EMR is a one size fits all sorbent for a variety of sample types and
analytes.
• Key applications were validated with EMR and demonstrate better recovery, better precision, and decreased matrix impact to the instrument and results.
March 17
NACRW 2015
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Today’s Agenda
IntroductionAddressing difficult samples1. Polar analytes2. High fat samples3. How to get rid of interfering terpenesSummary and Conclusions
NACRW 2015
1March 17
Constituents of Cannabis and Hop: Complex• Nitrogenous compounds (27 known)
• Amino acids (18),
• Proteins (3)
• Glycoproteins (6)
• Enzymes (2)
• Sugars and related compounds (34)
• Hydrocarbons (50)
• Simple alcohols (7)
• Aldehydes (13)
• Ketones (13)
• Simple acids (21)
• Fatty acids (22)
• Simple esters (12)
• Lactones (1)
• Steroids (11)
• Terpenes (120)
• Non-cannabinoid phenols (25)
• Cannabinoids (66)
• Flavonoids (21)
• Vitamins (1) [Vitamin A]
• Pigments (2)
• Elements (9).
56
9x10
0
0.05
0.1
0.15
0.2
0.25
0.3
0.35
0.4
0.45
0.5
0.55
0.6
0.65
0.7
0.75
0.8
0.85
0.9
0.95
1
1.05
1.1
1.15
1.2
1.25
1.3
1.35
1.4
1.45
1.5
1.55
1.6
1.65
1.7
1.75
1.81 1
Counts vs. Acquisition Time (min)4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32
QuEChERS AOAC Extraction/Partitioning with Custom dSPE versus Universal dSPE: Hops
57
GC/MSMS MS1 Scan
Universal dSPE
Custom B dSPECustom C dSPECustom D dSPE
Custom F dSPE
QuEChERS AOAC Extraction/Partitioning with Custom F dSPE versus Universal dSPE: Hops
58
Universal dSPE
Custom F
9x10
0
0.05
0.1
0.15
0.2
0.25
0.3
0.35
0.4
0.45
0.5
0.55
0.6
0.65
0.7
0.75
0.8
0.85
0.9
0.95
1
1.05
1.1
1.15
1.2
1.25
1.3
1.35
1.4
1.45
1.5
1.55
1.6
1.65
1.7
1.75
1.81 1
Counts vs. Acquisition Time (min)4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32
GC/MSMS MS1 Scan
59
QuEChERS AOAC Extraction/Partitioning with Custom F dSPE versus Universal dSPE: Hops
8x10
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1
1.1
1.2
1.3
1.4
1.5
1.6
1.7
1.8
1.9
2
2.1
2.2
2.3
2.4
2.5
2.6
2.7
2.8
2.9
3 1 1
Counts vs. Acquisition Time (min)4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32
GC/MSMS MS1 Scan
0
10
20
30
40
50
60
70
80
90
100
110
120
130
140
150
Re
co
ve
ry
Pesticide
QuEChERS AOAC with Custom F dSPE versus Universal dSPE
AOAC with Custom FAOAC with Universal dSPE
60
Pesticide Recovery after QuEChERS AOAC with Custom F dSPE or Universal dSPE: Hops
Daminozide is not extracted into the ACN layer after QuEChERS AOAC salt partitioning Concentration of spiked pesticides: 100 ppb
Conclusion
Addressing difficult samples1. Polar analytes : Explore new polymeric SPE phases2. High fat samples: Consider EMR Lipids as a dSPE3. How to get rid of interfering terpenes: stay tuned
NACRW 2015
1March 17
Thank You!
