Isotope dilution method for determination of polybrominated diphenyl ethers using liquid chromatography coupled to negative ionization atmospheric pressure photoionization tandem mass spectrometry: validation and application to house dust.

A total of 14 tetra- to deca- PBDE congeners were separated on a C(18) reversed phase liquid chromatographic column. PBDEs 47, 85, 99, 100, 153, 154, 183, 196, 197, 203, 206, 207, 208, and 209 were eluted using a gradient methanol/water/toluene mobile phase system at a flow rate of 0.5 mL min(-1). (13)C-BDE-47, (13)C-BDE-99, (13)C-BDE-153, BDE-128, and (13)C-BDE-209 were used as internal standards, while (13)C-BDE-100 was used as a syringe standard. Separated analytes were ionized using an atmospheric pressure photoionization (APPI) source equipped with a 10 eV krypton lamp and operated in negative ion mode. M-Br + O ions were monitored as precursor ions for all studied PBDEs, except for BDE-208 and BDE-209 which produced higher intensity at the C(6)Br(5)O ion cluster. Br ions were monitored as fragment ions for all target compounds. Method detection limits ranged from 12 to 30 pg. The method was applied to determination of PBDEs in standard reference material (SRM 2585), and favorable results were obtained. Unlike GC methods, no thermal degradation was encountered in the analysis of higher brominated PBDEs. This rendered the method useful for quantification of BDE-209 debromination products. The method also allows the use of (13)C-labeled internal standards, which compensate for instrumental fluctuations and matrix-related ion suppression or enhancement.