Determination of Polybrominated Diphenyl Ether Flame Retardants in Surface Water by Liquid Chromatography–Atmospheric Pressure Photoionization Tandem Mass Spectrometry

This study investigated the use of liquid chromatography–atmospheric pressure photoionization tandem mass spectrometry (LC-APPI-MS/MS) for the determination of six polybrominated diphenyl ethers (PBDEs) coded as brominated diphenyl ether (BDE) 28, 47, 99, 100, 153, and 154 that are used as flame retardants. It was shown that diphenyl ethers with four to six bromine atoms can be ionized in negative polarity with parent ions corresponding to [M-Br +O]−. On the contrary, the ionization of the diphenyl ether with three bromine atoms (BDE 28), required the use of positive polarity in order to generate precursor ions [M]+. PBDEs were separated by a C18 column (50 × 4.6 mm, 1.8 µm) with a mixture of methanol–water as the mobile phase following gradient elution. Instrumental limits of detection ranged from 41 to 119 pg on the column. The method was applied to surface water samples after liquid–liquid extraction with dichloromethane. Method limits of quantification ranged from 4.1 to 73 ng L−1 and recoveries ranged from 80.5 to 95%. The estimated analytical figures were appropriate for trace determination of PBDEs. PBDEs were found to be ionized with a similar mechanism as polychlorinated biphenyls and polychlorinated naphthalenes during LC-APPI-MS/MS analysis, indicating that this technique may be suitable for other polyhalogenated polyaromatic compounds present at trace levels in the environment.