Fant 9758 publikasjoner. Viser side 227 av 391:
2014
Hydrophilic organic pollutants - A threat to the Arctic? AMAP Report, 2002:2
2002
Hydrolysis of FTOH precursors, a simple method to account for some of the unknown PFAS
There is a growing concern over a suspected presense of unknown perfluoroaliphatic substances (PFAS) in consumer goods and in the environment. Such unknown substances, possibly with high molecular weight, might be precursors of hazardous or controlled known PFAS. Recent studies confirmed that total organic fluorine (TOF) content often can not be explained by the measured target PFAS. One of the suspected classes of such unknowns are polymers with fluorotelomer alcohol (FTOH) residues in a side chain. In this report we suggest hydrolysis of precursors, as a complementary method to account for the unknown PFAS. It was shown here that hydrolysis allows to preserve structural information on the perlfuorinated parts of the precursors, which can be an advantage for the purpose of accurate risk assessment or source identification. A convenient procedure for hydrolysis with 4% sodium hydroxide inwater-methanol mixture (1:9) at 60 C for 16 h was shown to convert model substances - FTOH acrylate, methacrylate and isobutyrate esters as well as FTOH phenylcarbamate to free FTOHs. Analysis of extracts of textile samples with preliminary hydrolysis and without it showed up to 1300-fold higher level of “hidden” FTOHs.
Pergamon Press
2021
2003
Hydrochlorofluorocarbon and hydrofluorocarbon emissions in East Asia determined by inverse modeling.
2010
Hydrochlorofluorocarbon and hydrofluorocarbon emissions in East Asia determined by inverse modeling. NILU PP
2010
Hydrochlorofluorocarbon and hydrofluorocarbon emissions in East Asia determined by inverse modeling.
2010
NILU and Hydro Aluminium performed a test campaign for measurements of CF4 and C2F6 for stack emissions at Husnes Aluminium Smelter. Time-integrated samples were taken with evacuated canisters combined with low-flow restrictors for continuous sampling periods as long as 6 weeks. The samples were analyzed at NILU with a Medusa preconcentration method combined with GC-MS SIM. As a main conclusion, time integrated sampling together with Medusa GC-MS methodology is a very precise alternative to the traditional attempts to quantify PFC-emission.
NILU
2022
2012
2015
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Norges forskningsråd
2024
2017
2003
2005
2023