Determination of the brominated flame retardant, hexabromocyclodocane, in sediments and biota by liquid chromatography-electrospray ionisation mass spectrometry

A method involving reversed-phase, liquid chromatography coupled to electrospray ionisation mass spectrometry (LC-ESI-MS) was developed for separation, detection and quantitation of the α-, β- and γ-diastereoisomers of hexabromocyclododecane (HBCD). To address the lack of environmental data of this high-production-volume chemical, and to begin to understand the behaviour, the fate and the effects of these stereoisomers, a diastereoisomer-specific method is necessary. Currently, HBCD stereomeric separation is not possible using gas chromatography; thermally-induced rearrangements as well as decomposition of the compound occur at temperatures >240°C by the initial elimination of hydrogen bromide. The extraction of HBCDs, and subsequent clean-up procedures are similar to those used for polybrominated diphenylethers, and include Soxhlet, homogenisation, mechanical shaking, sulphuric acid treatment and gel-permeation chromatography. Single-quadrupole and ion-trap mass analysers as well as LC separations were optimised using pure and individual HBCD stereoisomers, and determinations were performed using selected ion monitoring (m/z 640.7) of the [M-H]− ion. This article presents options for analyte extraction and information regarding instrument optimisation, and demonstrates that LC-MS is a suitable technique for quantifying HBCD stereoisomers in complex environmental matrices.