AFFF analysis with TOF-CIC, TOPA & LC-MS/MS: connecting the dots

Aqueous Film Forming Foams (AFFF) containing poly- and perfluoroalkyl substances (PFASs) have had widespread use in Australia including Defence sites (Department of Defence, 2017) and fire training areas (Parliament of Victoria, 2016). Historically, these AFFF had as their active ingredient perfluorooctane sulfonate (PFOS) which in May 2009 was added by the Fourth Conference of Parties to Annex B of the Stockholm Convention on Persistent Organic Pollutants coming into force on 26 August 2010. A National Industrial Chemicals Notification and Assessment Scheme (NICNAS) survey (Department of the Environment and Energy, 2009) conducted in 2008 revealed current stock of PFOS of 7,554 kilograms in firefighting foams and that the majority of products and mixtures containing PFOS imported into Australia in 2006 and 2007 were imported by the metal plating industry for use as mist suppressants (NICNAS, 2016). Following negotiations between US EPA (2000) and the 3M Company the company announced on 16 May 2000 that it will voluntarily phase out and find substitutes for PFOS chemistry used to produce a range of products, including some of their Scotchgard™ lines. 3M data supplied to USEPA indicated that these chemicals are very persistent in the environment, have a strong tendency to accumulate in human and animal tissues and could potentially pose a risk to human health and the environment over the long term. At that time 3M was the only US manufacturer of PFOS using the electrochemical fluorination (ECF) manufacturing technique. ECF is widely known to be a quite a "dirty" chemistry producing many side products including branched and linear isomers of PFOS plus unknown precursors. The composition of AFFF have therefore contained known and unknown amounts of fluorosurfactants such as PFOS and more recently the active ingredient has included new generation fluorotelomers such as 6:2 FTS (6:2 Fluorotelomer sulfonic acid) and 6:2 FTSAB (6:2 fluorotelomer sulfonamido betaine). The analysis of PFASs in AFFF by LC-MS/MS is presented as well as the determination of Total Organic Fluorine using Combustion Ion Chromatography (TOF-CIC). The gap between the results including the use of the Total Oxidisable Precursor Assay (TOPA) are discussed. (author)