Page 24 - Shimadzu Journal vol.7 Issue1

Environmental Analysis

⿏Growing List of PFAS Compounds ⿏Flexibility of Analytical Instruments
Due to the impact of PFAS on human health and the environment, EPA To incorporate the growing list of PFAS compounds and to enhance the
[18]
launched the 2010/2015 PFOA Stewardship Program in early 2006 to specificity and sensitivity of the LC-MS/MS analysis, Multiple Reaction
reduce and ultimately eliminate PFOA, PFOS and long-chain PFAS from Monitoring (MRM) is commonly utilized. Shimadzu’s Ultra-fast Mass
products and emissions. The eight participating companies with global Spectrometry (UFMS™) systems, featuring an ultra-fast acquisition rate
operations have either stopped the production and import of these of 555 MRM/sec and which can operate without any compromise in
selected PFAS and then switched to alternatives or entirely move away sensitivity, prove to be ideal for the fast and sensitive analysis of many
from the PFAS industry. PFAS compounds in a single run.
GenX process and technology has emerged as a substitute to PFOA and Shimadzu’s collision cell, UFsweeper™, is one of the key features that
PFOS; companies are able to make high-performance fluoropolymers contributes to the high acquisition rate. The redesign of the collision cell
(GenX chemicals), such as hexafluoropropylene oxide (HFPO) dimer acid allows for an ultra-fast ion sweeping where ions are efficiently
and its ammonium salts. With the recent recommendation for a global accelerated out of the collision cell without losing momentum. With
ban on PFOA and its related chemicals by the UN global scientific these features in Shimadzu UFMS™, short dwell time and pause time
2
1
committee , manufacturers and industries all over the world may turn are achieved and data can be acquired at a high speed with no loss in
[19]
to these GenX compounds as substitutes. sensitivity. With more time for data collection, the UFMS™ technology
addresses the need of large-compound-panel testing in PFAS analysis
These alternatives have raised several health and environmental
[20]
concerns as they possess similar properties as PFOA and PFOS . To and ensures potential extendibility of the LC-MS/MS method for PFAS.
accelerate occurrence assessment, the EPA updated the drinking water In this white paper, the state-of-the-art analytical methods for
method to EPA 537.1 Version 1.0 in November 2018 to include GenX monitoring PFAS are described, with emphasis on the work related to
[21]
(HFPO-dimer acid) and three other compounds (i.e. 11Dl-PF3OUdS, the validation of ASTM D7979. A robust method consisting of simple
9Cl-PF3ONS and ADONA, ) in addition to the target list. sample preparation with direct injection to LC-MS/MS (Shimadzu
[21]
LCMS-8060) is demonstrated, showcasing the setup, performance and
With the release of EPA’s Health Advisory for PFAS in 2017, the
availability of validated methods and increase of public awareness, PFAS compatibility of LCMS-8060 for the separation and analysis of 49 PFAS
monitoring and testing is becoming routine. Together with this trend of in environmental samples.
using similar compounds as alternatives, the list of PFAS that are of
concern may continue to grow.

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Experimental
100, 80, 60, 40, 20, 10 and 5 ng/L. These standards were not filtered.
⿏List of PFAS Compounds and Preparation of Calibration
Standards Calibration was performed using a 9-point curve, ranging from 5 – 200
ng/L. Due to the high method detection limit (MDL) obtained for FHEA,
Table 2 lists all 49 PFAS compounds (30 targets and 19 FOEA and FDEA, the calibration range for these compounds was
isotopically-labeled surrogates) used in this study. The list covers the adjusted to 100 – 4000 ng/L and calibration standards were prepared
PFAS compounds named in ASTM D7979 method and includes as described above.
additional compounds listed for consideration in the appendix of the The stock solutions were prepared and stored in PFAS-free
method. All PFAS standards were purchased from Wellington polypropylene (PP) containers. Prior to the analysis, the solutions were
Laboratories (Guelph, Ontario).
shaken thoroughly then transferred to a 2 mL amber glass LC vial, and
Stock standard solution at a concentration of 200 ng/L for all 49 analyzed within 24 hours to achieve optimum results. In the event that
compounds was prepared from the commercially available stock samples or standards are allowed to sit in the LC vials, some PFAS
solutions. The stock standard solution was further diluted using a compounds may settle, precipitate or adsorb on the surface. To ensure
50:50 (vol:vol) methanol/water with 0.1% acetic acid to obtain the a homogenous solution and optimum results, it is necessary to vortex
other eight calibration solutions; their final concentrations were at 150, the solution prior to injection.

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