Detection of Perfluorooctanesulfonic acid or perfluorooctane sulfonate (PFOS) and Perfluorooctanoic acid (PFOA) in waste water and other aqueous samples
The analysis for PFOS and PFOA is carried out using a Liquid Chromatography - Mass Spectrometry - Time of Flight (LC/MS-TOF) analyser. Aqueous samples are injected directly on to the analyser together with PFOS/PFOA calibration solutions and the PFOS/PFOA concentrations are calculated using multi-level peak area - concentration calibrations. PFOS/PFOA levels in solid samples, such as fluoropolymers and pigments, and can be determined by solvent extraction followed by LC/MS analysis of the extract.
PFOS is used in chromium plating, pesticides and hydraulic, aviation fluids. PFOS and PFOA are used to give grease, oil and water resistance to textiles and paper. They are also used in photolithography, floor polishes and fire fighting foams. PFOA is still used as a processing aid in the production of fluoropolymers such as polytetrafluoroethylene (PTFE), although its use is being phased out.
European Regulations classifies PFOS as toxic to aquatic organisms and bees, potentially causing long term adverse effects in the aquatic environment. EU Directive 2006/122/ECOF and subsequent amendments impose restrictions on PFOS usage and set the limit for PFOS in substances and preparations at 50 parts per billion (ppb). This directive also states that PFOA poses a similar risk to PFOS.