Application Note AS-300: Automated Enrichment and Clean Up of Water Samples for Analysis of PFAS
Per- and polyfluoroalkyl substances (PFAS) are a group of man-made chemicals that have been widely used in a variety of industrial and consumer products since the 1950s. These chemicals are known for their ability to resist heat, water, and oil, which is why they are commonly used in non-stick cookware, waterproof clothing, and firefighting foam.
Recent studies have found that PFAS can have negative effects on human health and the environment. These chemicals are known to be persistent, meaning they do not break down easily in the environment, and due to the hydrophobic nature of many of these chemicals they are able to bioaccumulate through the food chain. Studies have linked exposure to PFAS to a variety of health issues, including cancer, thyroid disease, and developmental delays in children.
Given the potential health and environmental risks associated with PFAS, the Stockholm convention has regulated the use of perfluorooctane sulfonic acid (PFOS) and perfluorooctanoic acid (PFOA). The European chemical agency (ECHA) on 13 January 2023 received a proposal for further restrictions from five member states to cover a wider range of PFAS chemicals.
In order to comply with regulations and guidelines water authorities are looking to analyse samples to ensure safe levels in drinking water. This is typically done using LC-MS/MS analysis. Low ng/L levels can be detected by direct injection of water using high end LC-MS/MS instruments, but these come with a relatively high price and does not allow any clean-up of samples so potentially reducing the lifetime of analytical columns.
At Element Cambridge we developed an automated method on a GERSTEL multipurpose sampler (MPS) utilising smart SPE (solid phase extraction), to both clean-up and enrich a variety of water types and sources. This method allows sub 1 ng/L limits of detection for a wide range of PFAS analytes. Thanks to the enrichment this method reduces the impact of sources of contamination associated with the analysis and allows low level detection on lower specification LC-MS/MS instruments.