Preliminary Assessment of Bioaccessibility of HBCDs from Human GIT following Indoor Dust Ingestion Using a Physiologically Based Extraction Test (PBET)

摘要

An in vitro PBET which incorporates human gastrointestinal tract (GIT) parameters (including pH and chemistry, solid-to-solution ratio, mixing and emptying rates) was applied to study the bioaccessibility of α-, β- and γ-HBCDs from the 3 main GIT compartments following ingestion of indoor dust. While the oral compartment was not studied due to the short residence time in this compartment; 1 gram of a well-characterised, sieved and homogenised indoor dust sample was incubated at each of a simulated stomach (pH=2), small intestine (pH=7) and colon (pH=6.5) compartments for 1, 4 and 8 hours respectively. A "control" group was obtained from a similar experimental setup but no dust added. Samples were freeze dried, extracted using pressurised liquid extraction and analysed using LC-NIESI- MS/MS. No target compounds were above the detection limit (0.5 ng g-1) in the control group. Results revealed that the average bioaccessibility of γ-HBCDs from the 3 studied GIT compartments (51%) was less than that for α- and β-HBCDs (82% and 69% respectively) which is probably due to the lower aqueous solubility of the γ-isomer (2 μg L-1) compared to the α- and β-isomers (45 and 15 μg L-1 respectively). The average overall bioaccessibility of ∑HBCDs from the 3 GIT compartments studied was 77%. No significant change in the enantiomeric fractions was observed in any of the studied samples.