Per- and polyfluoroalkyl substances (PFAS), widely used in products such as non-stick cookware, food packaging, waterproof textiles, and firefighting foams, do not readily break down and can accumulate in the environment. The newly published international standard ISO 18127 provides laboratories with a validated method for determining adsorbable organically bound halogens (AOX) and adsorbable organically bound fluorine (AOF) in water using combustion ion chromatography (CIC).
Addressing the fluorine gap in traditional methods
Historically, AOX determination was performed according to EN ISO 9562 or EPA 1650. These methods measure organically bound chlorine, bromine, and iodine but do not account for fluorine, providing only a partial picture when assessing contamination from fluorinated compounds. The inclusion of AOF within ISO 18127 introduces a screening parameter capable of indicating the presence of adsorbable organically bound fluorine in water samples.
Application across water matrices
The standard is suitable for a variety of water matrices, including groundwater, surface water, drinking water, cooling water, and wastewater. In addition to total AOX and AOF, the method enables separate quantification of organically bound chlorine, bromine, and iodine. Metrohm combustion ion chromatography specialists contributed to the development and validation of both DIN 38409-59 and ISO 18127.
For water authorities, environmental laboratories, and regulators seeking reliable PFAS screening methods, this standard represents a significant step forward in water quality monitoring and contamination assessment.
