Analytical characteristics and determination of major novel brominated flame retardants (NBFRs) in indoor dust

A new method was developed and optimized for the detection of major "novel" brominated flame retardants (NBFRs), which included decabromodiphenyl ethane (DBDPE), 1,2-bis(2,4,6-tribromophenoxy) ethane (BTBPE), tetrabromobisphenol A-bis(2,3-dibromopropylether) (TBBPA-DBPE), 2-ethylhexyl-2,3,4,5-tetrabromobenzoate (TBB), bis(2-ethylhexyl)-3,4,5,6-tetrabromophthalate (TBPH) and hexachlorocyclopentadienyl-dibromocyclooctane (HCDBCO). Several solid phase sorbents were tested, and finally, a two-step cleanup procedure was established. The first step on activated silica was used to fractionate the dust extracts, while the second step on acidified silica (silica gel impregnated with sulphuric acid 44% w/w) and on Florisil(®), respectively, was essential for advanced cleanup. High recoveries for NBFRs (range, 75-94%) were achieved. Analysis was performed by gas chromatography coupled with mass spectrometry in electron capture negative ionization using a DB-5ms (15 m × 0.25 mm × 0.1 μm) capillary column. Quantification of DBDPE, BTBPE and TBBPA-DBPE was based on ion m/z 79, while characteristic ions were used for quantification of TBB (m/z 359), HCDBCO (m/z 310) and TBPH (m/z 384). The method provided good repeatability; within- and between-day precision were ≤14% for all NBFRs. Method limits of quantification ranged between 1 and 20 ng g(-1); dust and NBFRs were not detected in blanks. The method was further applied to indoor dust (n = 21) collected from e-waste facilities in Thailand. Except for HCDBCO, all NBFRs were detected in the e-waste dust with concentrations up to 44,000 and 22,600 ng g(-1) DBDPE and BTBPE, respectively. The dust profile was dominated by DBDPE (50%) > BTBPE (45%) > TBBPA-DBPE (3%) > TBPH (1.9%) > TBB (0.1%). Significant correlations (p < 0.05) were found between the concentrations of BTBPE and BDE 183 or BDE 197 on the one hand, between TBPH and BDE 47 or BDE 99, and between DBDPE and BDE 209, on the other hand. Concentrations of TBB were not positively correlated with TBPH, which suggests different emission sources.