Hydroxylated transformation products obtained after UV irradiation of the current-use brominated flame retardants hexabromobenzene, pentabromotoluene, and pentabromoethylbenzene

Abstract

Hexabromobenzene (HBB), pentabromotoluene (PBT), and pentabromoethylbenzene (PBEB) are current-use brominated flame retardants (cuBFRs) which have been repeatedly detected in environmental samples. Since information on hydroxylated transformation products (OH-TPs) was scarcely available, the three polybrominated compounds were UV irradiated for 10 min in benzotrifluoride. Fractionation on silica gel enabled the separate collection and identification of OH-TPs. For more insights, aliquots of the separated OH-TPs were UV irradiated for another 50 min (60 min total UV irradiation time). The present investigation of polar UV irradiation products of HBB, PBT, and PBEB was successful in each case. Altogether, eight bromophenols were detected in the case of HBB (three Br3-, four Br4-, and one Br5-isomer), and nine OH-TPs were observed in the case of PBT/PBEB (six Br3- and three Br4-congeners). In either case, Br➔OH exchange was more relevant than H➔OH exchange. Also, such exchange was most relevant in meta- and ortho-positions. As a further point, and in agreement with other studies, the transformation rate decreased with decreasing degree of bromination. UV irradiation of HBB additionally resulted in the formation of tri- and tetrabrominated dihydroxylated compounds (brominated diphenols) that were subsequently identified. These dihydroxylated transformation products were found to be more stable than OH-TPs.

High Amounts of Halogenated Natural Products in Sperm Whales (Physeter macrocephalus) from Two Italian Regions in the Mediterranean Sea

“…GC-Orbitrap-ECNI-HRMS proved to be important in the virtual identification of the molecular formula due to the high precision of the exact mass determination. In the future, the presence of hydroxyl groups may also be verified by derivatization similar to the approach used for the verification of tetrabrominated diphenols as transformation products of the flame retardant hexabromobenzene …”

“…In the future, the presence of hydroxyl groups may also be verified by derivatization similar to the approach used for the verification of tetrabrominated diphenols as transformation products of the flame retardant hexabromobenzene. 62 …”

“…In the future, the presence of hydroxyl groups may also be verified by derivatization similar to the approach used for the verification of tetrabrominated diphenols as transformation products of the flame retardant hexabromobenzene. 62 On the one hand, OH-TriBHD (possessing the molecular formula C 16 H 19 Br 3 O 2 ) is a known HNP which was detected together with TriBHD and TetraBHD in its natural producer. 33,41 On the other hand, a hydroxylated TriBHD could also be a metabolite that could be generated by the sperm whales, e.g., in the liver.…”