PERFORCE3 Webinar 3: The total oxidizable precursor assay (TOPA): From research to regulation

  • Post category:Webinar
  • Reading time:2 mins read

Around 60 participants tuned in on May 12, 2021 to watch the PERFORCE3 webinar “The total oxidizable precursor assay (TOPA): From research to regulation” featuring Dr. Dorte Herzke (NILU), Lara Cioni (NILU) and Dr. Lena Vierke (UBA). The event consisted of short presentations followed by a lively discussion between the panellists and the audience. A recording of the event can be found below.



The decades-long production and use of a broad variety of PFAS in industrial applications, firefighting activities and consumer products has resulted in increasing contamination of the environment including groundwater and drinking water supplies throughout Europe.

A considerable proportion of European citizens is expected to exceed the tolerable weekly intake (TWI) due to intake of legacy PFAS from food and drinking water. The human exposure to PFAS by consumer products is expected to be still an important factor as well, due to the large number of known PFAS applications still in use. Existing data on environmental levels, bioaccumulation and human exposure of novel PFAS and exposure time-trends are however scarce, thereby hampering environmental fate mapping and systematic estimation of human exposure to PFASs as a group and consequently proper risk assessment and management.

New analytical tools are required to tackle the challenge of analyzing 100s of PFAS compounds per sample, many of them either of unknown identity or lacking commercially available standards. The total oxidizable precursor assay (TOPA) offers an approach to evaluate the presence of both known and unknown PFAS precursors in a variety of sample matrices.

In this webinar we introduce the concept of TOPA, detail the use of TOPA for identifying the presence and class of PFAS precursors, and outline some limitations to the approach. We follow up with some thoughts on TOPA as a potential tool for PFAS regulation under REACH.