Fig. 2From: Digging deep—implementation, standardisation and interpretation of a total oxidisable precursor (TOP) assay within the regulatory context of per- and polyfluoroalkyl substances (PFASs) in soilConcentrations of PFCA homologues and PFOS from a contaminated soil sample measured before and after in-house TOP assay protocols in an interlaboratory test with five contributing laboratories (L1–L5)Back to article page