PFAS Analysis: How to Minimize Contamination in Testing
by Ken Rosnack, principal market development manager, Food and Environmental Markets, Waters Corporation
PFAS (Per- and Polyfluoroalkyl substances)
are anthropogenic chemicals found in a
range of consumer goods and industrial
processes. Common uses include
firefighting foams 1 , water-resistant
coatings, floor polishes, and oil resistant
coatings for paper products approved
for food contact. Testing laboratories
have greater challenges today than ever
before to meet the low detection limits
and increased scope for PFAS defined by
PFAS are ubiquitous and due to their
widespread use and subsequent
leaching are frequently detected in the
environment, animals and humans. They
are also difficult to keep out of laboratory
background contamination. Due to
their omnipresent, persistent nature
and possible toxicity 2 , most regulatory
agencies 3 worldwide monitor the use,
occurrence and impact of traditional
long-chain and the newer short-chain
PFAS. These short-chain PFAS, such as
“GenX 4 ,” are increasingly being used as
replacements for the long-chain versions
such as PFOS and PFOA.
In addition to the cautions outlined above,
using a PFC Analysis Kit 7 is recommended.
It is comprised of components that
replace Teflon ® items with PEEK
counterparts and an isolator column to
help delay any LC system interferences
(see Figure 1). Relevant detection levels
can be met utilizing this kit, a sensitive
mass spectrometer (MS), and the sample
preparation described in the guideline,
regulatory or reference method being
used. On a mid-tier MS, such as the Waters
Xevo ™ TQ-S micro, an Oasis ™ WAX 8 solid
phase extraction is recommended to
enrich analytes by 100x to 250x. Should
direct injection onto an MS be desired, a
high performance MS such as the Waters ™
Xevo TQ-XS should be used.
Kari Organtini, senior scientist and PFAS expert at Waters
Corporation, standing next to the ACQUITY UPLC™ and the
Xevo TQ-S micro MS system. Photo: Waters Corporation
By following good laboratory practices to
minimize contamination and by choosing
a suitable analytical workflow, PFAS
testing can become less challenging and
more robust allowing routine, confident
reporting of analytical results. n
Influence of Contaminated Drinking Water on Perfluoroalkyl
Acid Levels in Human Serum – A Case Study from Uppsala,
Sweden, Irina Gyllenhammar et.al, https://www.sciencedirect.
com/science/article/pii/S0013935115001656, Accessed 04
PFAS Health Effects, Source: https://www.atsdr.cdc.gov/pfas/
health-effects.html, Accessed 04 December 2018.
PFAS Laws and Regulations, Source: https://www.epa.gov/pfas/
pfas-laws-and-regulations, Accessed 04 December 2018.
“GenX” is a brand name for a chemical process that utilizes
FRD-903 to produce FRD-902 and E1. See GenX Wikipedia
Entry, Source: https://en.wikipedia.org/wiki/GenX, Accessed 04
Region 5 CRL Methods for the Analysis of Polyfluorinated
Compounds (PFCs) Using a Quick Sample Extraction /
Preparation Followed by UPLC/MS/MS Analysis, Lawrence B.
Zintek et.al., National Environmental Monitoring Conference
Teflon is a registered trademark of the Chemours Company
used for polytetrafluoroethylene.
Analysis of Legacy and Emerging Perfluorinated Alkyl
Substances (PFAS) in Environmental Water Samples Using
Solid Phase Extraction (SPE) and LC-MS/MS (PFC Kit Waters
Part #176001744), Organtini et.al. Available from: http://www.
OASIS WAX Cartridge Product Information Page,
htm?partNumber=186002493, Accessed 04 December 2018.
Waters Corporation is a platinum level
sustaining member of APHL.
For routine monitoring and research
purposes, detection of PFAS to the ng/L,
ng/kg or part-per-trillion (ppt) level
requires the use of LC/MS/MS. However,
there are many common sources 5 of
PFAS contamination making it difficult
to routinely achieve such low level
analysis. Although complete avoidance
of PFAS is impossible, steps can be taken
to minimize background contributions.
In the field, caution should be taken to
avoid Teflon ®6 containing materials such
as waterproof clothing, plastic clipboards,
waterproof notebooks and chemical
ice packs. In the laboratory, items to
avoid include sticky notes, certain glass
disposable pipettes, aluminum foil,
vial caps with Teflon seals and LDPE
containers. It is recommended that all
laboratory supplies be checked for PFAS
contamination before use in the analysis.
System Isolator Column
Figure 1: PFC Analysis Kit installed in the Waters ACQUITY
UPLC showing main components. Photo: Waters Corporation
Winter 2019 LAB MATTERS