Trace-level Determination of Perfluorinated Compounds in Water

The human and environmental exposure potential of perfluorinated alkyl substances such as perfluorooctane sulfonate (PFOS) and perfluorooctanoate (PFOA) has become the subject of intense research. Metrohm
presents an easy-to-use and economic direct-injection method for PFOA and PFOS determination in drinking water.

The currently used method for the determination of anionic perfluorinated surfactants is LC-MS/MS. The analytical methods for the determination of PFOS and PFOA in water samples generally employ a C18-SPE column, either with or without ion pairing or acidification, followed by LCMS/ MS. However, this method suffers from relatively high running and investment costs.

The new Metrohm method is a good alternative regarding both investment on instrumentation and usability. The method is based on suppressed ion chromatography with isocratic elution on a reversed-phase column thermostated at 35°C using an aqueous mobile phase containing boric acid and acetonitrile. The used detection technique is conductivity.

While PFOA and PFOS determination in low salt-containing water samples can be performed using straightforward direct injection chromatography, samples with higher alkaline-earth-metal concentration, for example, tap, lake, sludge or river water samples, should pass over a cation exchanger such as Metrohm’s Sample Preparation Module «SPM» prior to separation.