Stability of fluorinated surfactants in advanced oxidation processes--A follow up of degradation products using flow injection-mass spectrometry, liquid chromatography-mass spectrometry and liquid chromatography-multiple stage mass spectrometry

The advanced oxidation process (AOP) reagents ozone (O3), O3/UV, O3/H2O2, and H2O2/Fe2+ (Fenton's reagent) were applied to the anionic and the non-ionic fluorinated surfactants perfluorooctanesulfonate (PFOS) and N-ethyl-N-(perfluoroalkyl)-sulfonyl-glycinic acid (HFOSA-glycinic acid) or N-ethyl-N-perfluoroalkyl sulfonylamido-2-ethanol polyethoxylates (NEtFASE-PEG), their methyl ethers (NEtFASE-PEG methyl ether) and partly fluorinated alkyl-ethoxylates (FAEO) dissolved in ultrapure water. To monitor the efficiencies of destruction samples were taken during the treatment period of 120 min. After sample concentration by C18-solid phase extraction (SPE) and desorption MS, coupled with atmospheric pressure chemical ionisation (APCI) or electrospray interface (ESI) was applied for detection. No elimination of PFOS was observed while HFOSA-glycinic acid and AOP treated non-ionic surfactants were eliminated by oxidation. Degradation products could be detected and identified. So PFOS was observed during HFOSA-glycinic acid oxidation. Polyethylene glycols (PEG) and PEG methyl ethers were generated from non-ionic fluorinated surfactants beside their oxidation products--aldehydes and acids--all identified by tandem (MS-MS) or multiple stage mass spectrometry (MSn). AOP treatment of FAEO blend resulted in a mixture of partly fluorinated alcohols, separated and identified using GC-MS.