lcmsms determination of polyfluoroalkyl substances (pfas) in … · 2017-06-15 · emr-lipids...
TRANSCRIPT
Determination of Polyfluoroalkyl
Substances (PFAS) in Food Products
Agustin Pierri, PhD
ASMS 2017
Indianapolis, IN
Background
Aliphatic backbone—from C4 on up
Typically per-fluorinated
Acid functional group
Unique environmental chemistry
Persistent
Lipophilic
Bioaccumulative
Polyfluoroalkyl Substances Polyfluoroalkyl Substances (PFASs)
Uses?
Repellents
Performance chemicals
Consumer and industrial goods
Polyfluoroalkyl Substances (PFASs)
Routes of exposure
Direct contact with food products
Environmental exposure
Polyfluoroalkyl Substances (PFASs)
Target compounds
• Carboxylic acids
• Sulfonic acids
• Sulfonamides
• Sulfonamido-ethanols
6:2 FTS 8:2 FTS EtFOSA MeFOSA FOSA
EtFOSE
MeFOSE
PFBA
PFBS
PFDA
PFDS
PFHpA
PFHpS
PFHxA
PFHxS
PFNA
PFOA
PFOS
PFPeA
PFDoA
PFTeDA
PFTrDA
PFUdA
Sample prep
Sample prep approach
SPE:
Only suitable for water samples
Weak anion exchange offline SPE
QuEChERS:
Suitable for non-liquid samples
QuEChERS
Screening:
C18 d-SPE
C18 d-SPE + hexanes
PSA/GCB d-SPE
C18/GCB d-SPE
C18/GCB d-SPE + hexanes
EMR-L
👎
👌👏
👎
👎
👎
👎
EMR-Lipids procedure
Weigh 2.0 grams homogenized sample into 50 mL tube
Add 2 g of EMR-L + 10 mL H2O
Vortex 1 minute, centrifuge 5 minutes
Transfer 5 mL aliquot to tube with 2.5 g NaCl/MgSO4
Transfer 200 µL to conical vial for analysis
Add 10 mL MeCN, vortex 3 minutes
Based on:
Anumol, T., Lehotay, S.J., Stevens, J. et al.
Anal Bioanal Chem (2017) 409: 2639
Analysis: LC/MS
PFAS by LC/MS
Unique analytical challenges
Low levels
Relative polarities
Isomers
Contamination
Sensitivity
1290 LC, 6460 QQQ
Choosing the right mobile phase modifier
Mobile phase modifiers for ESI
Negative mode
Ammonium salts
Ammonium acetate
Ammonium formate
Ammonium fluoride—the secret sauce (usually)
Mobile phase vs PFBA
Ammonium acetate
Acetic acid
Ammonium formate
Ammonium fluoride
Most polar: 👍
Chromatographic conditions
Column: Zorbax RRHD Eclipse Plus C18
50 x 2.1 1.8 μm
Injection volume: 2 μL
Mobile phase: A: Water with 0.05% acetic acid
B: Acetonitrile with 0.05% acetic acid
Flow rate: 0.700 mL/min Time %B
0.0 5
0.5 5
1.0 40
7.0 90
7.2 100
9.5 100
Mid level chromatogram (1 ppb)
Low level (0.1 ppb)
Low levels: 👍
Solvent blank
Instrument contamination: 👍
Branched vs. linear sulfonates
Isobars: 👍
PFOS PFHxS
Dynamic range
Calibrates up to 0.1 ppb – 1000 ppb
Method performance
Extracts Egg Milk Fish Butter Blank
Absolute recoveries, milk
0
20
40
60
80
100
120
140
160
PFB
A
PFP
eA
PFB
S
PFH
xA
PFH
pA
PFH
xS
6:2
FTS
PFO
A
PFH
pS
PFO
S
PFN
A
FOSA
Me-F
OSE
8:2
FTS
Me-F
OSA
PFD
A
Et-
FOSE
Et-
FOSA
PFD
S
PFU
dA
PFD
oA
PFT
rDA
PFT
eD
A
Milk, ESTD
0
20
40
60
80
100
120
140
160
PFB
A
PFP
eA
PFB
S
PFH
xA
PFH
pA
PFH
xS
6:2
FTS
PFO
A
PFH
pS
PFO
S
PFN
A
FOSA
Me-F
OSE
8:2
FTS
Me-F
OSA
PFD
A
Et-
FOSE
Et-
FOSA
PFD
S
PFU
dA
PFD
oA
PFT
rDA
PFT
eD
A
Egg, ESTD
Absolute recoveries, egg
Absolute recoveries, butter
0
20
40
60
80
100
120
140
160
PFB
A
PFP
eA
PFB
S
PFH
xA
PFH
pA
PFH
xS
6:2
FTS
PFO
A
PFH
pS
PFO
S
PFN
A
FOSA
Me-F
OSE
8:2
FTS
Me-F
OSA
PFD
A
Et-
FOSE
Et-
FOSA
PFD
S
PFU
dA
PFD
oA
PFT
rDA
PFT
eD
A
Butter, ESTD
0
20
40
60
80
100
120
140
160
PFB
A
PFP
eA
PFB
S
PFH
xA
PFH
pA
PFH
xS
6:2
FTS
PFO
A
PFH
pS
PFO
S
PFN
A
FOSA
Me-F
OSE
8:2
FTS
Me-F
OSA
PFD
A
Et-
FOSE
Et-
FOSA
PFD
S
PFU
dA
PFD
oA
PFT
rDA
PFT
eD
A
Fish, ESTD
Absolute recoveries
0
20
40
60
80
100
120
140
160
PFB
A
PFP
eA
PFB
S
PFH
xA
PFH
pA
PFH
xS
6:2
FTS
PFO
A
PFH
pS
PFO
S
PFN
A
FOSA
Me-F
OSE
8:2
FTS
Me-F
OSA
PFD
A
Et-
FOSE
Et-
FOSA
PFD
S
PFU
dA
PFD
oA
PFT
rDA
PFT
eD
A
Milk, ISTD
Isotopic dilution corrected recoveries, milk
0
20
40
60
80
100
120
140
160
PFB
A
PFP
eA
PFB
S
PFH
xA
PFH
pA
PFH
xS
6:2
FTS
PFO
A
PFH
pS
PFO
S
PFN
A
FOSA
Me-F
OSE
8:2
FTS
Me-F
OSA
PFD
A
Et-
FOSE
Et-
FOSA
PFD
S
PFU
dA
PFD
oA
PFT
rDA
PFT
eD
A
Milk, ESTD
0
20
40
60
80
100
120
140
160
PFB
A
PFP
eA
PFB
S
PFH
xA
PFH
pA
PFH
xS
6:2
FTS
PFO
A
PFH
pS
PFO
S
PFN
A
FOSA
Me-F
OSE
8:2
FTS
Me-F
OSA
PFD
A
Et-
FOSE
Et-
FOSA
PFD
S
PFU
dA
PFD
oA
PFT
rDA
PFT
eD
A
Egg, ISTD
Isotopic dilution corrected recoveries, egg
0
20
40
60
80
100
120
140
160
PFB
A
PFP
eA
PFB
S
PFH
xA
PFH
pA
PFH
xS
6:2
FTS
PFO
A
PFH
pS
PFO
S
PFN
A
FOSA
Me-F
OSE
8:2
FTS
Me-F
OSA
PFD
A
Et-
FOSE
Et-
FOSA
PFD
S
PFU
dA
PFD
oA
PFT
rDA
PFT
eD
A
Egg, ESTD
0
20
40
60
80
100
120
140
160
PFB
A
PFP
eA
PFB
S
PFH
xA
PFH
pA
PFH
xS
6:2
FTS
PFO
A
PFH
pS
PFO
S
PFN
A
FOSA
Me-F
OSE
8:2
FTS
Me-F
OSA
PFD
A
Et-
FOSE
Et-
FOSA
PFD
S
PFU
dA
PFD
oA
PFT
rDA
PFT
eD
A
Butter, ESTD
0
20
40
60
80
100
120
140
160
PFB
A
PFP
eA
PFB
S
PFH
xA
PFH
pA
PFH
xS
6:2
FTS
PFO
A
PFH
pS
PFO
S
PFN
A
FOSA
Me-F
OSE
8:2
FTS
Me-F
OSA
PFD
A
Et-
FOSE
Et-
FOSA
PFD
S
PFU
dA
PFD
oA
PFT
rDA
PFT
eD
A
Butter, ISTD
Isotopic dilution corrected recoveries
0
20
40
60
80
100
120
140
160
PFB
A
PFP
eA
PFB
S
PFH
xA
PFH
pA
PFH
xS
6:2
FTS
PFO
A
PFH
pS
PFO
S
PFN
A
FOSA
Me-F
OSE
8:2
FTS
Me-F
OSA
PFD
A
Et-
FOSE
Et-
FOSA
PFD
S
PFU
dA
PFD
oA
PFT
rDA
PFT
eD
A
Fish, ISTD
Isotopic dilution corrected recoveries
0
20
40
60
80
100
120
140
160
PFB
A
PFP
eA
PFB
S
PFH
xA
PFH
pA
PFH
xS
6:2
FTS
PFO
A
PFH
pS
PFO
S
PFN
A
FOSA
Me-F
OSE
8:2
FTS
Me-F
OSA
PFD
A
Et-
FOSE
Et-
FOSA
PFD
S
PFU
dA
PFD
oA
PFT
rDA
PFT
eD
A
Fish, ESTD
Robust and versatile method for PFAS in food
Challenges unique to PFAS
Trace levels—MRL at 0.5 ng/g
Instrument contamination
Resolution
Handle complicated matrix
0
20
40
60
80
100
120
140
160P
FBA
PFP
eA
PFB
S
PFH
xA
PFH
pA
PFH
xS
6:2
FTS
PFO
A
PFH
pS
PFO
S
PFN
A
FOSA
Me-F
OSE
8:2
FTS
Me-F
OSA
PFD
A
Et-
FOSE
Et-
FOSA
PFD
S
PFU
dA
PFD
oA
PFT
rDA
PFT
eD
A
Butter, ISTD
