Determination of flame-retardant hexabromocyclododecane diastereomers in textiles.

To establish a concise and rapid procedure to analyze hexabromocyclododecane (HBCD) diastereomers in flame-retarded textiles, three different methods of extraction-Soxhlet, ultrasonic, and soaking extractions with toluene and dichloromethane (DCM)-were compared. During Soxhlet extraction using toluene, the percent contribution of alpha-HBCD to total HBCDs increased slightly and that of gamma-HBCD decreased, indicating that gamma-HBCD was isomerized to some extent at the boiling point of toluene (110.6 degrees C). For ultrasonic extraction, the temperature of the water bath can easily increase over time during the procedure, which might lead to undesirable effects. Therefore, we considered soaking extraction with DCM to be the most facile procedure to analyze HBCD diastereomers in textiles. Using the method established in this study, commercially available textiles in Japan (n=10) were analyzed to understand the actual composition of HBCD contents and its diastereomer profiles. With the exception of one textile sample, HBCDs were detected in all the samples analyzed, with concentrations ranging from 22000 to 43000 mg kg(-1) (i.e. 2.2-4.3%). We found a higher proportion of the alpha-diastereomer in most textile products compared with that of commercial HBCD mixtures, indicating that gamma-HBCD isomerized to alpha-diastereomer by heating processes to incorporate the commercial formulation into treated materials or that the alpha-diastereomer preferentially absorbed onto textile materials during the manufacturing of flame-retarded consumer products.