Enantiomeric specific determination of hexabromocyclododecane by liquid chromatography–quadrupole linear ion trap mass spectrometry in sediment samples

Abstract

This paper describes the determination and quantitation of hexabromocyclododecane (HBCD) enantiomers by liquid chromatography–quadrupole linear ion trap mass spectrometry (LC–QqLIT-MS). The method is based on the use of a chiral chromatographic column Nucleodex β-PM (200 mm × 4.0 mm, 5 μm), which allows a good separation between HBCD enantiomers [(±)α, (±)β and (±)γ] in less than 15 min and the detection is performed by a Q-Trap instrument. Linearity was checked between 0.05 and 25 injected ng. Limits of detection (LODs) were in the range of 0.3–1.5 pg, limits of quantification (LOQs) were between 1 and 6 pg, and both values are lower than those published in the literature applying LC–MS–MS methods. The method was applied to sediment samples collected along the Cinca River, a tributary of the Ebro River (northeast of Spain). Samples were extracted and purified following a pressurized liquid extraction method. LODs of the method were between 0.12 and 5.61 ng/g and LOQs, from 0.38 to 1.87 ng/g. Total HBCD levels in these sediments ranged from not detected to 2660 ng/g dry weight. Enantiomeric fractions (EFs) were calculated and compared with EF obtained from standard injections. It is important to note that calculated EFs were corrected using 2H 18-labeled HBCD standards, in order to compensate matrix effect. EFs obtained in sediment samples suggested a higher presence of (+)α-HBCD and (+)γ-HBCD in technical mixture, this suggests that it is not a racemic mixture.