Simultaneous determination of α-, β- and γ-hexabromocyclododecane diastereoisomers in water samples by isotope dilution mass spectrometry using 81Br-labeled analogs

This work describes the synthesis, characterization and application of three 81Br-labeled diastereosiomers of hexabromocyclododecane (HBCD) for the accurate and precise determination of α-, β- and γ-HBCD in water samples by isotope dilution mass spectrometry. The synthesis of the labeled analogs was carried out by bromination of cis, trans, trans-1,5,9-cyclododecatriene with 81Br-enriched bromine. After isolation and purification by semipreparative HPLC, each diastereoisomer was characterized in terms of concentration and isotopic enrichment. Then, they were added to the samples to simultaneously quantify the three HBCD diastereoisomers in a single LC-MS/MS injection without resorting to a methodological calibration graph. The results obtained here demonstrate that the use of 81Br-labeled analogs provides accurate and precise determinations of α-, β- and γ-HBCD in real water samples. The limits of quantification obtained in real samples for α-, β- and γ-HBCD were 0.022, 0.073 and 0.015 ng L−1, respectively, significantly lower than those required by the European Directive 2013/39/EC.