Non-targeted Analysis of California Drinking Water using Point-Of-Use Filters

Non-targeted Analysis
of California Drinking
Water using Point of
Use Filters
Seth Newton
US EPA Office of Research and
Development
PFAS Science Call
August 19, 2024

Vet Clinic PowerPoint Template
What is Non-targeted Analysis (NTA)?
3
Targeted
Analysis
Non-targeted
Analysis
• Targeted focused on 10s-
100s of preselected
chemicals
• Quantitative – reference
standards are used to make
calibration curves
• Certain
• Can screen for the presence of
1000s of known chemicals or
identify previously unknown
chemicals
• Generally non-quantitative –
although quantitative methods
are under development
• Uncertain
?

› Because targeted methods exist for
<1% of known chemicals
› End goal: detect chemicals you would
otherwise miss using only target
methods
› See “Introduction to NTA (from EPA)”
video at:
https://nontargetedanalysis.org/additio
nal-resources/videos/
2
Why NTA?

› Pilot scale using Point of Use
(POU) filters
› Demonstrated POU filters can
capture a variety of chemicals
› Many more compounds exist in
drinking water than are currently
known
› LC only
Previous Study
2
Why Use POU Filters?
Future Goals
› Develop extraction method that
works for GC and LC NTA
› Understand how p-chem
properties affect extraction
efficiencies
› Apply on a larger scale
› Pros:
› Large sample volume
› Easy transport
› Wide variety of compounds
› Cons:
› Difficult to extract
› Doesn’t fit many faucets
Pros and Cons

Extract 1:
Sonication in
Acetone:DCM
Liquid/Liquid
Extraction to
separate DCM from
residual water
Extract 1
Extract 2: Sonication in
Methanol
Extracts 1 and
2 combined
1 mL
aliquot
Reduced
to 1 mL
NTA by LC-HRMS
NTA by GC-HRMS
Extraction and Sample Preparation Method
*Image from Sloop et al., “Method development for non-targeted analysis of point-of-use drinking water filters using GC-MS and LC-MS”, In Preparation

The Tapwater Analysis Project (TAP)
3
Background Sampling
• Funded by the California
Breast Cancer Research
Program
• Involved multiple government
agencies, universities/
research institutes, and
community groups
• To investigate contaminants
in drinking water that may
increase risk of breast cancer
• 60 residences in five regions of
California targeting high
regional breast cancer rates
and high contamination
• Grab samples for targeted
testing of pesticides,
pharmaceuticals, disinfection
biproducts, and PFAS
• 46 POU filter samples for non-
targeted analysis
GOLD
NCV
KERN
SELA
BA-SF

Vet Clinic PowerPoint Template 2
Data Processing Workflow
LC-HRMS
GC-HRMS
MS2
MS1
PCI and NCI
EI
DSSTox
MSReady
Formulas
Manual Molecular
Ion Search
Candidate
Prioritization

ToxPi = +
Candidate Prioritization
Meta Data + Spectral Matches =
What’s Most Likely to be Correct?
ToxPi =
What’s Most Interesting?

2
Confirmed Chemicals
Tris(2-chloroisopropyl)
phosphate
DEET Butylated
hydroxytoluene
Di(2-ethylhexyl) phthalate
• Confirmed 21 chemical identifications via LC-NTA
Diethyl maleate
Bromoform 1,2 Dichlorobenzene Dimethyl phthalate Atrazine Simazine
• Confirmed 17 chemical identifications via GC-NTA

Confirmed PFAS
• Same occurrence pattern as targeted PFAS
4-Trifluoromethylpiperidine
Fragrance, preservative
PFOS
PFBS
PFOA PFHxA

Unconfirmed Novel PFAS - PFECHS
Perfluoro-p-ethylcyclohexylsulfonic
acid
DTXSID70275965
• Same occurrence pattern as other PFAS

Unconfirmed Novel PFAS - Fluoromatch
Methyl 2-hydroxy-4-(2,2,3,3,3-
pentafluoropropoxy)benzoate
Perfluoro-2-methoxyacetic
acid
Perfluoro-4-
propylcyclopentane-1-
carboxylic acid
1-(1,1,2,2-tetrafluoroethyl)-
Cyclohexanecarboxylic acid

› Point of Use filters are convenient and
viable samplers for a wide range of
GC- and LC-amenable compounds
› Far more compounds exist in drinking
water than we can currently identify
› Exposure and hazard data should be
considered in prioritization
› Product use data can be indicative of
contaminant source
2
Conclusions

Project Team
Seth R. Newton, EPA ORD
John T. Sloop, NIEHS
Gina Solomon, Public Health Institute
Jonathan Casey, EPA Region 3
Kristin Isaacs, EPA ORD
Hannah Liberatore, EPA ORD
Peggy Reynolds, Univ of CA San Francisco
Julie von Behren, Univ of CA San Francisco
Disclaimer: The views expressed in this presentation are those of the author(s) and do not
necessarily represent the views or policies of the US Environmental Protection Agency.

How NTA works – formula generation
-0.857 min, 4 scans) Frag=135.0V TAP_Nootkatone_1uM_Pos_MS2_05092023.d Subtract
305.1553
306.1596
Counts vs. Mass-to-Charge (m/z)
4.6 304.8 305 305.2 305.4 305.6 305.8 306 306.2 306.4 306.6 306.8 307 307.2 307.4 307.6 307.8
346.2049
347.1972
348.1980
0.9923
1.9931
1) Accurate
Mass
2) Isotope
Abundance
3) Isotope
Spacing
100%
13%
4%
C22H28N2O

How NTA works – mass defect
C8F17O3S = 498.929668
6
x10
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
-ESI Scan (rt: 12.940-13.007 min, 5 scans) Frag=135.0V NYCATL_Neg_MS1_TracerBlk2_1.d
502.9430
503.9457
504.9396
Counts vs. Mass-to-Charge (m/z)
502.75 503 503.25 503.5 503.75 504 504.25 504.5 504.75 505 505.25 505.5 505.75
498.9297
499.9290
500.9254

How NTA works – MS2 Spectral Matching

Chemical Name Product Count
Butylated hydroxytoluene 13,503
Ethylparaben 4,840
Dibutyl phthalate 1,277
Benzyl butylphthalate 1,038
Octaethylene glycol 1,025
Di-(2-ethylhexyl)phthalate 891
Tributyl citrate 795
DEET 422
Dimethyl phthalate 357
1,2-Dichlorobenzene 246
Product Uses - ChemExpo
Product Use Category Product Count
Personal care 18,805
Home maintenance 836
Cleaning products and household care 470
Pesticides 398
Other direct contact consumer goods 396
Laboratory supplies 328
Food and drug 269
Raw materials 151
Vehicle 117
Arts and crafts/office supplies 99
Almost 90% of the Personal Care products contain either Butylated hydroxytoluene or Ethylparaben
* Slide from John Sloop

Non-targeted Analysis of California Drinking Water using Point-Of-Use Filters

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