Fluorinated organic substances gained in importance in recent decades, because substitution with fluorine holds many beneficial characteristics for the application. Not only fluorinated polymers, such as polytetrafluorethylene (PTFE, Teflon®) are encountered at many places in everyday life, but many low-molecular organic substances also contain one or several fluorine atoms, for example, some pharmacologically active substances, such as fluoxetine, as well as pesticides, such as tolylfluanide. In the past decade perfluoroalkyl and polyfluoroalkyl (PFASs, formerly also PFC = perfluorinated and polyfluorinated compounds or PFT = "perfluorinated tensides") gained great attention.
This class of substances of which perfluorooctanoic acid (PFOA) and perfluorooctane sulfonic acid (PFOS) are the most researched substances, have many negative properties for people and the environment.
Since the common methods of today for the quantification of known substances utilize methods with a defined analyte spectrum, mainly the high performance liquid chromatography coupled with the tandem mass spectrometry (HPLC-MS/MS), unknown compounds of this substance class are not detected by the method. However, some studies lead to the result that the content of unknown PFASs in environmental samples exceeds that of specific individual substances.