Page 23 - Shimadzu Journal vol.7 Issue1

Environmental Analysis

Ultra-fast LC-MS/MS Analysis of PFAS in Environmental Samples

2
1
1
Brahm Prakash , Cindy Lee , Gerard Byrne , Tairo Ogura 1
1 Shimadzu Scientific Instruments, USA.
2 Marketing Innovation Centre, Singapore.
There is increasing concern about the persistence and effects of Per- and Polyfluorinated Alkyl Substances (PFAS) in the environment. This white
paper summarizes the state-of-the-art analytical methods for monitoring PFAS and demonstrates the use, speed and performance of Shimadzu
Ultra-fast Mass Spectrometry (UFMS™) for PFAS analysis in environmental waters. The described method consists of a simple methanol dilution,
followed by a direct injection to LC-MS/MS. The Triple Quadrupole MS, LCMS-8060, was used in this study to effectively separate and quantify
49 PFAS, with all compounds eluting within 13 minutes. The stability of PFAS and the effect of solvents, vials and vortex on the recovery were
studied. Method detection limit of 0.6 – 5.4 ng/L, recovery of 84 – 113% and calibration range of 5 – 200 ng/L were achieved for 94% of the
PFAS compounds studied, including all the compounds listed in ASTM D7979. With high scan speed and short dwell time, the Shimadzu
LCMS-8060 demonstrates to be fast, sensitive, and robust for PFAS analysis in environmental waters.

Keywords:
Per- and Polyfluorinated Alkyl Substances, PFAS, Perfluorinated compounds, PFCs, Environmental, Surface Water, Non-Potable Water,
Groundwater, Wastewater, PFOA, PFOS, Persistent Organic Pollutants, POPs

Introduction
⿏Increasing Need to Monitor PFAS are no standard EPA methods available. US EPA is currently developing
EPA Method 8327 for the analysis of PFAS in environmental waters
[15]
Per- and Polyfluorinated Alkyl Substances (PFAS) are a group of using LC-MS/MS. In the interim, laboratories are using in-house
anthropogenic chemicals that are highly stable and resistant to developed methods (e.g. modified EPA Method 537) or methods that
degradation. These chemicals are manufactured and used in many have been developed by non-governmental standardization bodies,
consumer and industrial products (e.g. food packaging materials, such as ASTM International and ISO.
fire-fighting foams and textiles) due to their heat-resistant and oil- and ASTM International has developed ASTM D7979-17 and ASTM
[16]
water-repellent properties. As these PFAS compounds are persistent, D7968-17a for PFAS analysis in environmental waters and soil,
[17]
toxic and potentially harmful to humans [1], [2], [3], the leaching and respectively. The main difference between these ASTM methods lies in
presence of PFAS in our environment have raised serious concerns the sample preparation steps. After the extraction of samples, the
globally. procedures and LC-MS/MS methods are essentially the same.
Exposure to PFAS through drinking water and various environmental Shimadzu is one of the members of the ASTM D19.06 Task Group’s
sources has been studied and determined [4], [5], [6], [7] . In May 2016, the independent, second laboratory validation of ASTM D7979. This white
United States Environmental Protection Agency (US EPA) issued a paper describes the work related to the validation. Table 1 summarizes
health advisory of 70 parts per trillion (ppt) for combined PFOA and the various LC-MS/MS methods for PFAS testing in various
PFOS in drinking water . Several states in the US (e.g. California, environmental water and soil matrices.
[8]
Minnesota, New Jersey, Colorado, Massachusetts, Vermont and
Michigan) have followed the advisory and established similar or even Table 1 Comparison between the various EPA and ASTM Methods for PFAS
stricter guideline levels for PFAS, which can go to 13-14 ppt [9], [10] [11] . ɹɹɹ testing in water matrices.
Recent research has suggested that occurrence of PFAS compounds in Method EPA 537 [14] ASTM D7979 [16] ASTM D7968 [17] EPA 8327 [15]
tap water is markedly different by region and around the world . 14 Targets 21 Targets 21 Targets
[13]
[12]
24 PFAS compounds
Growing evidence highlights the obvious need to continuously monitor PFAS Compounds 3 Surrogates 9 Surrogates 9 Surrogates (details to be
3 ISTDs announced)
the water sources as well as drinking water to keep PFAS exposure
Groundwater,
under control. Sludge, Influent, Surface water and
Sample Matrices Drinking Water Effluent and Soil Wastewater. Sample
Wastewater (<0.2% collection procedure
solids) to be prescribed
⿏Validated Methods for Analyzing PFAS
Dilute 5 mL with 5 Extract 2 g with 10
Sample
Liquid chromatography coupled to triple-quadrupole mass Preparation 250 mL ˠ SPE ˠ mL Methanol ˠ mL 50% Methanol Direct Injection
ˠ Filter ˠ Direct
Filter ˠ Direct
1 mL
Method
spectrometry (LC-MS/MS) is widely used for the determination of PFAS Injection Injection
in water matrices because of its high sensitivity and specificity. Given
Injection Volume 10 µL 30 µL 30 µL To be announced
the social importance of PFAS monitoring, standardized analytical
methods for LC-MS/MS need to be developed and validated to ensure External Calibration External Calibration
(Isotope Dilution or
(Isotope Dilution or
Quantitation Internal Standard To be announced
that all results are consistent and reliable, particularly if the data were Internal Standard Internal Standard
allowed) allowed)
to be used for enforcing regulation.
In September 2009, US EPA published EPA Method 537 Version 1.1 [14]
for the determination of fourteen PFAS compounds in drinking water.
This method was later employed for the monitoring of the selected
PFAS during the Unregulated Contaminant Monitoring Rule 3
(UCMR3). However, for environmental waters (e.g. non-potable water,
surface water, wastewater and groundwater) and soil matrices, there
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