Analytical Methodologies for Per/Poly Fluoroalkyl ... · PFAS Instrument Setup Background...
Transcript of Analytical Methodologies for Per/Poly Fluoroalkyl ... · PFAS Instrument Setup Background...
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Analytical Methodologies for Per/Poly Fluoroalkyl Substances (PFAS) Measurement in Environmental Waters by LC/MS/MS
Tarun Anumol, Ph.D.Applications Development ScientistAgilent Technologies Inc.Wilmington, DE, USA
Contact: [email protected]
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Agilent ASTS-Houston
‘Fit for Purpose’ Analysis
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Considerations when selecting analytical technique to employ
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I. Types of analytesII. Concentrations required (ppm,
ppb, ppt etc.)III. Type of matrix (drinking water,
surface water, wastewater, sludge, food etc.)
IV. Type of sample clean-up required V. Regulatory considerations (EPA
methods, EU & ASTM methods etc.)
Factors in deciding analytical method selection
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Terminology
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• Terminology of these compounds can be confusing but it is critical to understand the differences
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TerminologyFluorinated Compounds
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Any organic or inorganic compound that has a fluorine atom incorporated in it
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TerminologyPer/PolyfluoroAlkyl Substances (PFAS)
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R: Continuation of alkyl chain or functional group
When one or more Carbons (C) in an alkyl chain have the Hydrogen (H) replaced by Fluorine (F)
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Terminology
Polyfluoroalkyl substance
ALL H atoms linked to C in alkyl chain are substituted with F
SOME (but not all) H atoms linked to C in alkyl chain are substituted with F
Perfluoroalkyl substance
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TerminologyPerfluoroalkyl acids (PFAAs)
• Perfluorocarboxylic acids (PFCAs)
• Perfluorosulfonic acids (PFSAs)
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TerminologyPolyfluorinated compounds - Fluorotelomers
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6:2 FTUCA
8:2 FTUCA
6-C alkyl chain: Hydrophobic 2-C: Hydrophilic
• Formed during the telomerization process in manufacturing
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Per/Polyfluoroalkyl substancesUnique Properties
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• Thermal & Chemical stability: grease-proof food packaging, stain repellents
• Zwitterionic properties: surfactants • Surface-tension lowering: fire-fighting foams
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Per/Polyfluoroalkyl substancesToxicology & Regulations in US
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Toxicological data:
• PFAS exposure can have adverse effects to the neurological and reproductive systems
• Long chain (>7-C chain) PFASs are bio accumulative, and persistent• Long half-lives for longer chain PFAS• Very difficult to degrade the final products (PFCAs, PFSAs) in the environment
Regulatory Overview:
• USEPA has a public health guidance for PFOA and PFOS at 70 ng/L in drinking water• Many states have their own health guidelines ranging from 20-400 ng/L for PFOS,
PFOA, PFNA and PFHxA
Agilent ASTS-Houston
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PFAS Analysis – LC Instrument SetupEliminate Background Contamination
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Application Note: Recommended Plumbing Configurations for Reduction in Per/Polyfluoroalkyl Substance Background with Agilent 1260/1290 Infinity (II) LC’s (5991-7863EN)
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PFAS Analysis – LC SetupEliminate Background Contamination
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PFAS Instrument SetupBackground Contamination
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Actual PFOS peak
5 ng/L standard
Mili-Q Water (‘Blank’)
Background PFOS from LC system
• The use of a Delay column is convenient when running multiple methods on the same instrument.
• “Delay” column and not a “Trapping” column. I.e. the background peak will be retention time separated but will be present.
• The delay column does not account for any contamination after the pump (the autosampler)
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250 mL sample collected in Polypropylene Bottles with 5 g/L Trizma (to quench residual chlorine)
Solid Phase Extraction and evaporation to final 1 mL extract in ~96/4 MeOH/Water
Analysis by LC-MS/MS in Negative Electrospray mode for 14 analytes (9 PFCAs, 3 PFSAs, 2 FOSAAs) – 37 min analysis (10 µL injection)
EPA 537: Perfluorinated Alkyl Acids in Drinking Water by SPE-LC/MS/MS
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Confidentiality Label
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Solid Phase ExtractionUSEPA 537 vs Modified
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Recoveries calculated in Reagent Water
Modified SPE cartridge: Agilent SampliQ WAX cartridge (6 cc, 150 mg)
All recoveries between 70-130 %
Spiking concentrations:
Modified SPE: 4 ng/L in 250 mLEPA 537: 5-21 ng/L in 250 mL
Final extract: 1 mL ~95% MeOH
PFHxA
PFHpA
PFOA
PFNA
PFDA
PFUdA
PFDoA
PFTrDA
PFTeDA
PFBS
PFHxS
PFOS
N-MeF
OSAA
N-EtFOSAA 0
25
50
75
100
125
150EPA 537 (n=7)Modified SPE (n=6)
Rec
over
y (%
)
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Agilent ASTS-Houston
Typical LC/TQ Lab Layout
6 feet1.83 meters
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Quick Change Ion Injector
Fast Ion Injector exchange without system venting
Ion Injector Tool VacShield
Easy to use, increased throughput, less downtime for maintenance
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Easy Change Detector Assembly
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Analysis of PFAS in Drinking Water with UltivoEPA Method 537
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Analysis of 17 PFASs in drinking water with <0.1 ng/mL DLs in extract (includes all comps in EPA 537)
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Analysis of PFAS in Drinking Water with UltivoEPA Method 537
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PFOS - 7 Levels, 7 Levels Used, 14 Points, 14 Points Used, 0 QCs
Concentration (ng/
-1 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21
Res
pons
es
3x10
-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
2.8
3
y = 147.003489 * x + 20.563484 R^2 = 0.99890136 Type:Linear, Origin:Ignore, Weight:NonePFOA - 7 Levels, 7 Levels Used, 14 Points, 14 Points Used, 0 QCs
Concentration (ng/
-1 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21
Res
pons
es
4x10
-0.5
0
0.5
1
1.5
2
2.5
3
3.5
4
4.5
5
5.5
6
y = 3046.084833 * x + 1326.038272 R^2 = 0.99894706 Type:Linear, Origin:Ignore, Weight:None
PFOS PFOA
Calibration Curves from 0.1-20 ng/mL for PFOA and PFOS
Post-spike recoveries of 17 PFASs in a water sample extracted according to EPA 537 with Agilent SampliQ WAX cartridges
Ultivo Triple Quad LC/MS
• All 17 PFASs had linear calibration curves, with R2 > 0.99
• Overall recoveries were between 70–125% for both spiking levels
• %RSD was 0.3–10.8 %for all compounds at both spiking levels (1.0 μg/L and 5.0 μg/L)
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Analysis of 30 PFASs in Drinking WaterAgilent 1260 Infinity II + 6470 Triple Quadrupole LC-MS
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Application Note: Analysis of Per/Polyfluoroalkyl Substances in Water Using an Agilent 6470 Triple Quadrupole LC/MS (5991-7951EN)
Chromatogram depicting MRM transitions of 30 PFASs post-spiked in a drinking water extract at 1 µg/L
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Analysis of 30 PFASs in Drinking WaterAgilent 1260 Infinity II + 6470 Triple Quadrupole LC-MS
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Sensitivity (0.08 ng/L equil. In water) Precision
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Analysis of Environmental Contaminants by LC-MS/MSIon Suppression Comparison by Sample Prep Method
Conventional SPEMass on Column :150 pg
Online SPEMass on Column :150 pg
Direct InjectionMass on Column :150 pg
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Agilent 6495 Triple Quadrupole LC/MSUltimate Sensitivity, Extreme Reproducibility
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8/8/2017Agilent 6495 QQQ LC/MS System
Agilent Jet Stream Hexabore Capillary Dual Ion Funnel
• Thermal gradient focusing• Efficient desolvation • Creates an ion rich zone
• Six capillary inlets• Samples x10 times more
ion rich gas
• Removes the gas but captures the ions
• Removes neutral noise
Agilent 6495 LC/TQ
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Perfluorinated Alkyl Acids in Drinking Water by LC/TQCollaborative work with Suffolk County Water Authority
• 1290 Infinity LC coupled to a 6490 LC-MS/MS
• 14 PFAAs in 6 min
System
• PFOA, PFOS: <1 ng/L• Others: 1-10 ng/L• 80 µL aqueous injection
MDLs:
• Drinking Water• Surface Water• Ground Water
Matrices:
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2x10
-0.1
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1
Cpd 9: PFHpA: -ESI MRM Frag=380.0V CF=0.000 DF=0.000 [email protected] (362.90000 -> 169.00000) Cal Std ppb 2.d
1.66 2.02
1 1
Counts (%) vs. Acquisition Time (min)0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8 2 2.2 2.4 2.6 2.8 3 3.2 3.4 3.6 3.8 4 4.2
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Analysis of PFOA/PFOSDirect Injection; Rapid Analysis (1290 II UHPLC + 6495 LC-MS/MS)
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PFOS
PFOA
10 ng/L standard
• Use Multi-wash function!!!• PFOS sticks to needle and seat especially
with long worklists
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Targeted Analysis LC-MS/MS vs LC-Q/TOF
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PFHxSPFOA
PFOS
PFHxSPFOA
PFOS0
20
40
60LC-MS/MSLC-QTOF
Con
cent
ratio
n (n
g/L)
Influent Effluent
Collaborative project with RMIT University, Melbourne (Timothy Coggan ; Prof. Bradley Clarke)
Agilent 6550 LC-Q/TOF
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Suspect ScreeningPersonal Compounds Database and Library with Spectra• Custom PFAS database with 106 compounds• MS/MS spectra and Retention time data available for a subset of compounds
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Untargeted Analysis
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Untargeted AnalysisIdentification of Novel PFAS
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Inclusion list for targeted MS/MS and structural elucidation using fragment information using software tools (Molecular structure correlator)
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Conclusions
Background contamination of PFASs is prevalent in ALL systems but can be fixed through systematic elimination of fluoropolymers in the LC.The Ultivo Triple Quad LC/MS offers significantly more sensitivity than
EPA 537 analysis while using a smaller footprint through several innovative technologies.The sensitive analysis of several newer classes of PFASs is possible
using the Ultivo and 6470.Rapid analysis of PFOA/PFOS and PFAAs can be performed by direct
large volume aqueous injection using the 6495 with <1 ng/L MDLs.Identification, screening and quantification of ‘emerging’ PFASs has
been shown using the Agilent LC-QTOF
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References
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5991-8156EN
5991-7951EN 5991-7863EN
5991-5669EN