Development of a new method for the enantiomer specific determination of HBCD using an ion trap mass spectrometer

An alternative method for the enantiomer specific determination of hexabromocyclododecanes (HBCD) by LC-ESI-MS/MS using an ion trap analyser is proposed. The method is based on the formation of a chlorine adduct (m/z 676.6) of the (+/-)alpha-, (+/-)beta-, and (+/-)gamma-HBCD enantiomers and their further fragmentation into their stable quasi-molecular ion (m/z 640.6). In this way, problems related to the ion trap low mass cutoff and variable amounts of other adduct peaks in the samples are solved. Parameters affecting separation, ionisation and MS/MS detection were studied. Method performance was also evaluated: calibration curves were found linear from 20 to 400 pg microL(-1) for each enantiomer; detection limits ranged between 1.5 and 4.3 pg microL(-1); repeatability and reproducibility, expressed as relative standard deviation, were lower than 6% and 13%, respectively. The application to different types of spiked samples (pork meat, lean fish, and butter) pointed out the occurrence of matrix effects that could be solved by using labelled standards.