Determination of polybrominated diphenyl ethers in pine needles using ultrasonic-assisted extraction and gas chromatography-negative chemical ionization-mass spectrometry

A method for the determination of polybrominated diphenyl ethers (PBDEs) in pine needles was developed. Ultrasonic-assisted extraction (UAE) was employed with n-hexane-acetone (1 : 1, v/v), and concentrated H2SO4 and an alumina column were used for cleaning-up the extract of pine needles. The final extract was identified and quantified for the 8 PBDE congeners (BDE-28, 47, 99, 100, 153, 154, 183, and 209) by gas chromatography-negative chemical ionization-mass spectrometry (GC-NCI-MS) with internal standard method in the selective ion monitoring (SIM) mode. The recoveries of the spiked standards ranged from 83.8% to 107.5%. The instrumental detection limits for tri- to hepta-BDEs (BDE-28, 47, 99, 100, 153, 154 and 183) were in the range of 0.152 -0.770 pg, and for BDE-209 was 11.1 pg. The method detection limits for the above-mentioned PBDEs were 3 - 15 pg/g wet weight and 222 pg/g wet weight, respectively. The results indicate that the method has high sensitivity, satisfactory recovery and good reproducibility. BDE-209 was found to be the dominant congener (82.3% of the total of 8 PBDEs), and BDE-47 was the major congener among the lower brominated congeners.