Detection and speciation of brominated flame retardants in high-impact polystyrene (HIPS) polymers

Polymeric materials have been suggested as possible environmental sources of persistent organic pollutants such as flame retardants. In situ, micrometre-scale characterization techniques for polymer matrix containing flame retardants may provide some insight into the dominant environmental transfer mechanism(s) of these brominated compounds. In this work, we demonstrate that micro X-ray fluorescence spectroscopy (μXRF), focused ion beam scanning electron microscopy (FIB-SEM) combined with energy dispersive X-ray spectroscopy (EDS), and time-of-flight secondary ion mass spectrometry (ToF-SIMS) are promising techniques for the elemental and chemical identification of brominated fire retardant compounds (such as the deca-congener of polybrominated diphenyl ether, BDE-209) within polymeric materials (e.g. high-impact polystyrene or HIPS). Data from μXRF demonstrated that bromine (Br) inclusions were evenly distributed throughout the HIPS samples, whereas FIB SEM-EDS analysis revealed that small antimony (Sb) and Br inclusions are present, and regionally higher concentrations of Br surround the Sb inclusions (compared to the bulk material). Four prominent mass-to-charge ratio peaks (m/z 485, 487, 489 and 491) that correspond to BDE-209 were identified by ToF-SIMS and can be used to chemically distinguish this molecule on the surface of polymeric materials with respect to other brominated organic molecules. These techniques can be important in any study that investigates the route of entry to the environmental surroundings of BDE-containing materials.