Automated Sample Preparation for Determination of Perfluoroalkyl and Polyfluoroalkyl Substances (PFAS)

Polyfluoroalkyl Substances (PFAS) in the Environment - Session 5
Oral Presentation

Presented by A. Köpf
Prepared by
1 - Shimadzu, Wharfside Trafford Wharf Road, Manchester, Manchester, 00000, United Kingdom
2 - Shimadzu Scientific Instruments, 7102 Riverwood Drive, Columbia, MD, 21046, United States
3 - Imperial College London, School of Public Health, , London, United Kingdom


Contact Information: wiererf@LCTech.de; +49808227170


ABSTRACT

Abstract: Over 60 years, perfluoroalkyl and polyfluoroalkyl substances (PFAS) are used in everyday materials with non-stick coatings. They get into the environment during manufacturing process, use and disposal. Sewage plants are mostly not able to purify waste-water with PFAS, so it accumulates in sewage sludge, that is often used in agriculture. The chemicals reaches the groundwater and get absorbed again through plants. Humans mostly incorporate PFAS through food or contaminated drinking water. PFAS are anthropogenic and considered non-biodegradable. Therefore, PFAS can be found globally in the environment, wildlife, human tissues and blood. The group of substances includes more than 3000 different compounds. Perfluorooctane sulfonic acid (PFOS), its salts and perfluorooctane sulfonyl fluoride were listed in the annex B of the Convention at the fourth meeting of the Conference to the Stockholm Convention on Persistent Organic Pollutants in 2009 and is evaluating PFOA and PFHxS for listing which makes the topic of PFAS present more than ever. Analytically, the determination of PFAS using LC/MS-MS methods is challenging and not yet harmonized as is for other POPs such as PCDD/PCDF but the sample preparation holds the same challenges for laboratories independent of regional regulation. One key challenge is to keep the background of analytes as low as possible as PFAS are spread all over the globe and are found ubiquitously. Additionally, fluorocarbon materials, commonly used in laboratory systems due to their chemical properties, are prone to a release of small amounts of PFAS that may significantly increase background levels. Therefore, any fluorocarbon materials of the FREESTYLE SPE or FREESTYLE XANA system were consequently removed and replaced by polyethylene or polypropylene, respectively. The presentation shows that environmental (e.g. soil, water), as well es biota (e.g. animal tissure, food), PFAS samples can be prepared fully-automated overcoming the daily shortages. Results are according to different regulations e.g. EPA Method 537.1 or the European DIN 38407-42.
Selected PFAS were processed on a FREESTYLE-PFAS system to see whether all compounds are recovered and do not adhere to the system. To prove the background free sample preparation, PFAS background levels of neat solvents, spiked and pure samples were compared.
The analytical targets of the applied method were found with good recoveries and very low standard variations resulting from the reliable and robust automation.
Due to the specifically designed PFAS system, which is virtually free of fluorocarbon compounds, any blank values stemming from the system are minimised. This was shown by PFAS background measurements of the instrument that were equal to the values obtained with neat solvent. Furthermore, by the application of fully automated parallel sample preparation, multiple samples can be processed at the same time on the FREESTYLE XANA system. Thus, a high sample throughput at low demand of personnel resources is obtained.