Stable carbon isotope analysis (δ13C values) of polybrominated diphenyl ethers and their UV-transformation products

Polybrominated diphenyl ethers (PBDEs) are frequently detected in food and environmental samples. We used compound specific isotope analysis to determine the δ13C values of individual PBDEs in two technical mixtures. Within the same technical product (DE-71 or DE-79), BDE congeners were the more depleted in 13C the higher brominated they were. In contrast, the products of light-induced hydrodebromination of BDE 47 and technical DE-79 were more enriched in 13C because of more stable bonds between 13C and bromine. As a result, the δ13C values of the irradiated solution progressed diametrically compared to those of the technical synthesis. The ratio of the δ13C values of BDE 47 to BDE 99 and of BDE 99 to BDE 153 are thus suggested as indicators to distinguish native technical products from transformation products. Ratios <1 are typical for native congeners (e.g. in DE-71) while the reversed ratio (>1) is typical of transformation products.

► δ13C values of PBDEs were determined by means of compound specific isotope analysis. ► PBDEs in technical mixtures were the more depleted in 13C the higher they were brominated. ► Solutions of individual PBDEs and technical PBDE mixtures were irradiated by UV light. ► δ13C values of irradiated PBDEs and technical PBDEs progressed diametrically. ► Ratios of the δ13C values were used to distinguish native from transformed PBDEs.