Method for the determination of sub-ppm concentrations of perfluoroalkylsulfonate anions in water

Abstract

The determination of sub-ppm concentrations of aqueous perfluoroalkylsulfonate (PFSt) anions, including perfluorooctylsulfonate (PFOS), has been accomplished with a relatively simple mass spectrometric procedure that does not require extraction of the analytes into an organic solvent or a chromatographic separation prior to injection into the negative-ion electrospray ionization mass spectrometer. Sample pretreatment was minimized and consisted of dilution of the aqueous samples of groundwater, surface water, tap water, and distilled water with acetonitrile, addition of dodecylsulfate (DDS) as an internal standard, and, in some cases, addition of known amounts of perfluorobutylsulfonate (PFBS) or PFOS for standard-addition experiments. The linear-response range for PFOS is 25.0 microg L(-1) to 2.5 mg L(-1). The lower limit of this range is three orders of magnitude lower than an equally straightforward chromatographic method. The relative errors for standard aqueous solutions containing only 25.0 microg L(-1) and 2.5 mg L(-1) PFOS are +/- 14% and +/- 7%, respectively, with 133 microg L(-1) DDS as the internal standard. The detection limit and quantification limit for PFOS in these standards are 5.0 microg L(-1) and 25.0 microg L(-1), respectively. Six different PFS anions, containing three to eight carbon atoms, were identified and quantified in an aqueous film-forming foam (AFFF) formulation using the method of standard additions. Two alkylsulfate anions and two perfluoroalkylcarboxylate anions were also identified in the AFFF formulation.

Quantitative determination of perfluorinated surfactants in water by LC-ESI-MS/MS

“…In order to cope with the problem of ionization suppression, internal standards such as carboxylic acids [25] or tetrahydroperfluorooctane sulfonate (THPFOS) [4,10] have been suggested. On the other hand, both are now recognized as problematic: carboxylic acids have lower acidity and surface activity than the PFS, and THPFOS may be present in environmental samples.…”

Fast screening of perfluorooctane sulfonate in water using vortex-assisted liquid–liquid microextraction coupled to liquid chromatography–mass spectrometry

“…The use of a glass surface has been found not to interfere with the extraction procedure [6,8,19]. For extraction, 50 L of octanol (the low density solvent acting as the acceptor phase) was slowly introduced and the mixture was vigorously shaken using a vortex agitator from Reax Control (Heidolph, Germany) for 2 min at 2500 rpm (maximum setting) leading to the formation of fine droplets.…”

LC-MS analysis in the aquatic environment and in water treatment technology ? a critical review

“…PFOS have been measured using LC-ESI-MS methods [74,75] and LC-APPI-MS by automated online extraction via on-line switching and turbulent flow chromatography [76].…”