Development of a sample preparation protocol for fast fluorine screening of sealing materials—Considering potential PFAS regulations

Elastomers commonly used as sealing materials are highly networked rubbery polymers. They may contain different pollutants such as fluorinated compounds like per- and polyfluoroalkyl substances (PFAS), for example used as additives to enhance the performance of the elastomer under a variety of chemical and mechanical stresses. As of now, no reliable recycling strategy for elastomers is available and they are consequentially disposed of by incineration or in landfills. Due to the potential wash out of additives or other pollutants into landfill leachates, elastomers present a possible source of continuous environmental pollution. A processing protocol for elastomers is required as a basis to enable the reliable determination of extractable fluorine: Here, we describe a quick and robust sample preparation protocol to determine extractable fluorine in various sealing materials. The optimization was aimed for time efficiency and robustness of results; sample preparation was conducted for fluorine sum parameter analysis via high resolution-continuum source-graphite furnace molecular absorption spectrometry (HR-CS-GFMAS). Samples were first roughly shredded to 2 mm and then further milled and sieved to defined particle size fractions. Different size fractions were tested and the extraction of the size fraction between 125 and 250 µm was found to be the best trade-off between extraction efficiency, time efficiency and sample loss. Subsequent methanolic or aqueous extraction and HR-CS-GFMAS analysis of various polymer samples revealed quantifiable extractable fluorine content for most samples. In the future, the sample processing method developed could make a valuable contribution as a standard operating procedure (SOP) for a time-efficient sample preparation for subsequent extraction and screening of sealing materials in prospect of the strict regulation on PFAS proposed by the European Chemicals Agency (ECHA).