Simultaneous extraction and determination of HBCD isomers and TBBPA by ASE and LC–MSMS in fish

Since the EFSA enquired a call for data for TBBPA and HBCD in 2009, the analytical determination of these compounds in food became of regulatory interest. Therefore, a method for the simultaneous determination of TBBPA and the three major HBCD stereoisomers was developed. Conventional techniques like soxhlet, ASE, GPC, sulphuric acid digestion, and acidified silica SPE are generally used in sample pre-treatment while detection is mostly performed by LC–MSMS. A combined analysis of HBCD and TBBPA is problematic due to the hydroxyl groups in the TBBPA molecule. However, using a specific mesh-size sodium sulphate in ASE extraction and an acid silica column combined with a Sep-pack Plus silica cartridge for purification resulted in recoveries between 80% and 110% for all compounds. The accuracy and reproducibility determined using proficiency test samples were 104% and 4% for the sum of the HBCD isomers. Typical limits of detection were 0.01 ng/g product or 0.004 ng on column, while the linear dynamic range is between 0.01 ng and 10 ng on column. Levels of TBBPA and HBCD isomers were determined in eel samples. TBBPA was occasionally detected and only marginally above the quantification limit of 0.05 ng/g, whereas total amounts of HBCD were between 0.2 and 150 ng/g with α-HBCD being the dominant HBCD isomer.