Per- and polyfluoroalkyl substances (PFAS) are a class of manmade organofluorine compounds. They are more commonly known as «forever chemicals» due to their extreme stability. PFAS are resistant to water, oil, and heat. Due to their unique properties, they find widespread applications in many products and industries. Because of their ubiquity, PFAS can enter the water supply and the food chain, causing various health problems in humans.

The EU Directive 2020/2184 suggests a maximum value of 0.50 μg/L for total PFAS or 0.10 μg/L for longer chain PFAS as a minimum requirement to assess the quality of potable water. Several norms are already in place for targeted PFAS analysis (e.g., ASTM D7979 and US EPA Methods 533, 537.1, and 1633). However, these PFAS testing methods do not cover the majority of these substances. Furthermore, expensive analytical instrumentation and experience is required to analyze PFAS individually.

Non-targeted screening methods offer a more comprehensive view of water quality by estimating the overall impact of organofluorine substances. One such method is the determination of the sum of all adsorbable organic fluorine (AOF). Measuring AOF with combustion ion chromatography (CIC) is simpler and faster than targeted PFAS analysis methods, and also more sensitive than total fluorine (TF) determination (comprising all organic and inorganic fluorine).

Measurement of AOF in water samples as an initial screening step gives a fast overview of the actual amount of organic fluorinated compounds present. This can be followed by targeted analyses of individual PFAS if indicated by higher AOF concentrations.

This White Paper covers the following topics:
 

• The general history of PFAS
• How they can enter the food chain, and how they affect our health
• Analytical methods for determining PFAS compounds
• Adsorbable organic fluorine (AOF) as non-targeted test for PFAS