Determination of polybrominated diphenyl ethers in coastal and river sediments by pressurized liquid extraction coupled with gas chromatography-mass spectrometry

This study presents a time- and solvent-saving method, pressurized liquid extraction (PLE), to extract polybrominated diphenyl ethers (PBDEs) in sediment samples. The effects of various operating parameters (i.e., extraction solution, temperature, pressure, static/dynamic extraction times) for the quantitative extraction of PBDEs by home-made PLE were systematically investigated and optimized. The analytes were then identified and quantitated by gas chromatography-mass spectrometry (GC-MS) in selected ion monitoring (SIM) mode. The 16 PBDE congeners (from tri- to deca-BDE) can be completely extracted by dichloromethane: n-hexane (3/2, v/v) at 100 °C and 100 atm combined with 15 min static and then 15 min dynamic extraction steps. Recovery of PBDEs in spiked sediment samples ranged from 52 to 104% with 2-16% RSD, except for BDE-206. Limits of quantitation (LOQ) were established between 4 and 400 pg/g (dry weight) in 10 g of sediment sample. The extraction efficiency of the PLE was also compared with the traditional Soxhlet extraction method. The total contents of PBDEs ranged from 8.0 to 37.9 ng/g (dry weight) in various river and coastal sediment samples in Taiwan. Deca-BDE (BDE-209) was the major PBDE detected in these sediment samples.