Method development for investigating 20 PFAS in snow samples from a background region Michaela Porkerta,c; Marion Greilingerb; Felix Happenhoferc; Martin Gregoric; Anne Kasper-Giebla aTU Wien, Institute of Chemical Technologies and Analytics, Getreidemarkt 9 1060 Vienna Austria bGeoSphere Austria, Hohe Warte 38 1190 Vienna Austria cMAPAG GmbH Industriestraße 7 2352 Gumpoldskirchen Austria Due to its properties as scavenger, snow is already used as a suitable medium for observing pollutants in the atmosphere. Per- and polyfluorinated alkyl substances (PFAS) are ubiquitous in the environment and gain increased attention due to their property as endocrine disruptor and more generally their adverse effects on health and on the environment. PFAS have numerous industrial applications as surfactant as well as in ski waxes. Thus, they can be released directly into the environment. To compare potentially contaminated regions, it is required to enable the detection of PFAS in background regions. Because of their stability, persistence and their possible harmful effects, it is important to further increase the understanding of atmospheric transport of PFAS. The Analysis was done by HPLC-MS/MS (Vanquish Duo Altis Plus, Thermo Fisher Scientific) and direct injection. The system was provided with an R18 apolar column of 10 cm length and a defender guard column of 2 cm. The mobile phase was a gradient of water, methanol and acetic acid and an ammonium acetate puffer was used for stabilization. The evaluation is done by external standards and fourteen individual C13 spiked standard substances. With this method recoveries from 83 to 105% with a relative standard deviation of max 5% for 20 different PFAS are reached. The 20 chosen substances are common degradation products of often used PFAS and precursors. Limits of detection (LODs) were calculated based on the blank samples and were between 0.04 ng/L for PFDoS to 0.77 ng/L for PFBA. An additional SPE purification is necessary to detect lower concentrations of background regions even, if it comes with smaller recoveries for certain PFAS especially the short and the long-chained molecules. With SPE purification LODs ranging from 0,005 ng/L to 0.052 ng/L can be achieved [1]. Snow, rime and glacier samples from a background region in the alps in middle Europe were provided by GeoSphere Austria from “Hoher Sonnblick” in Salzburg. The detected concentrations were between <LOD to 84.3 ng/L for the sum of 20 PFAS. This highlights the importance of lowering the detection limits. Details of the comparison between direct analysis and a preconcentration with SPE will be shown. [1] Xiaoping Wang, Mengke Chen, Ping Gong, Chuanfei Wang; Perfluorinated alkyl substances in snow as an atmospheric tracer for tracking the interactions between westerly winds and the Indian Monsoon over western China; Environment International, Volume 124, 2019, https://doi.org/10.1016/j.envint.2018.12.057