8
In PFAS analysis, we are currently discussing a target analyte list of 20, 30 or 40 compounds? However, the number of compounds in the PFAS universe has been estimated at 5000 and even as high as 8,000 which doesn’t include potential degradation products. Toxicity is largely a function of the unique chemical and configurational state of a molecule that controls the biochemical interaction with the organism. So, there is much more analytical work to identify the most important PFAS compounds from a toxicity perspective.
Excellent work is being done with accurate mass and advanced data analysis to give us a broader understanding of the chemical complexity of the PFAS universe. However, given the complexity and extent of the problem of environmental PFAS contamination, it is clear that a lot of hard work has yet to be done.
Acknowledgements Figure 8. Cheese Recoveries (QuEChERs:1 ng/g, n=4).
The contribution of Dr Agustin Pierri and his team at Weck Laboratories, City of Industry, California, USA is gratefully acknowledged.
References
1. Analytical Results of Testing Food for PFAS from Environmental Contamination. (
https://www.fda.gov/food//chemicals/analytical-results-testing-pfas-environmental- contamination), US Food and Drug Administration, October 20, 2020.
2. Basic Information about PFAS (
https://www.epa.gov/pfas/basic-information-pfas), US Environmental Protection Agency, December 06, 2018.
3. Toxicological Profile for Perfluoroalkyls (
https://www.atsdr.cdc.gov/toxicprofiles/ tp.asp?id=1117&tid=237), Agency for Toxic Substances and Disease Registry, Communicable Disease Center, September 30, 2020.
4. FDA Removes Approval for the Use of PFCs in Food Packaging Based on the Abandonment. (
https://www.fda.gov/food/cfsan-constituent-updates/fda-removes- approval-use-pfcs-food-packaging-based-abandonment), US Food and Drug Administration, November 21, 2016.
Figure 9. Egg Recoveries (QuEChERs: 1 ng/g, n=4).
5. Development of the Proposed Unregulated Contaminant Monitoring Rule for the Fifth Monitoring Cycle (UCMR 5): Public Meeting and Webinar (
https://www.epa.gov/ sites/production/files/2019-10/documents/ucmr5-stakeholdermeeting-190830.pdf), US Environmental Protection Agency, July 16, 2019
6. Installations Conducting Assessments for PFAS use or Potential Release. (https://
media.defense.gov/2020/Mar/17/2002265608/-1/-1/1/MAP_OF_INSTALLATIONS_ CONDUCTING_ASSESSMENTS_FOR_PFAS_USE_OR_POTENTIAL_RELEASE.PDF), US Department of Defense, September 30, 2019.
7. Per and Polyfluoroalkyl Substances (PFAS) (
https://www.fda.gov/food/chemicals/ and-polyfluoroalkyl-substances-pfas), US Food and Drug Administration, December 20,2019.
8. Per- and Polyfluorinated Alkyl Substances (PFAS) from Milk, Eggs, Butter, Cheese and Fish using QuEChERs, SPE and LC-MS/MS. Agustin Pierri Weck Laboratories) and Scott Krepich (Phenomenex, Inc,). Phenomenex Technical Note TN-0124 (https://
phenomenex.blob.core.windows.net/documents/a9406d77-c88e-49cb-9347- 81efd828fc25.pdf), Phenomenex, Inc., 2018.
Figure 10. (Egg Recoveries (QuEChERs + SPE: 0.1 ng/g, n=4). Read, Share and Comment on this Article, visit:
www.labmate-online.com/article Unique Technology Provides High Efficiency Solid Phase Extraction
INTip Solid Phase Extraction (pipette tips containing sorbent) from DPX Technologies utilises a patented technology known as Dispersive Pipette XTRaction. This device is unique from all other SPE devices because sorbent is loosely contained within a pipette tip. The disperser in XTR tips helps to perturb the sample solution and loose sorbent during aspirate and dispense steps. This mixing provides a highly efficient interaction of the sorbent with the analyte of interest resulting in ideal analyte recoveries and reduced matrix effects.
Traditional SPE in the form of cartridges or 96-well plate options allow sample, wash and elution solvents to flow through the sorbent in one direction. SPE cartridges are not automation compatible with most high throughput platforms. While 96-well plate formats are amenable to automation, additional hardware like a vacuum or positive pressure manifold is required. Dispersive Pipette XTRaction takes seconds due to the efficiency of dispersive mixing, and entire workflows can be completely automated in as little as five minutes. INTip SPE is a cost effective SPE solution reducing not only direct costs, but in-direct costs including solvent consumption and LC-MS/MS maintenance. Dispersive Pipette XTRaction methods are versatile and can be customised for specific workflows, including those requiring high sensitivity and/or utilising low sample volume.
Pipette tips are easy-to-use and easy-to-automate. XTR tips are available on Hamilton Robotics, Gerstel, epMotion, Integra Systems and manual handheld pipettors. XTR tips can hold 1 - 100 mg of sorbent depending on the tip size and format. Sorbent chemistries are available in a range of phases for selectivity of a diverse spectrum of analytes. DPX offers complete customisation of the sorbent inside the tip to allow for varying masses, mixed mode combinations and options like adding salt necessary for SALLE (Salt Assisted Liquid-Liquid Extraction). Adding salt (S) to sorbents like WAX or RP (example WAX-S or RP-S) creates an easy way to perform SALLE with the added cleanup mechanism of the SPE sorbent. There are a number of applications notes and publication references on the DPX website for Dispersive Pipette XTRaction methods.
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INTERNATIONAL LABMATE - FEBRUARY 2021
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