超声辅助碱解萃取-气相色谱-电子捕获检测器测定海洋沉积物中8种多溴联苯醚

将超声辅助碱液分解杂质与溶剂萃取相结合,采用气相色谱-电子捕获检测(GC-ECD)建立了一种快速高效净化、萃取海洋沉积物中8种常见多溴联苯醚(PBDEs)的分析方法。样品在2.00 mol/L NaOH甲醇溶液中超声30 min,经正己烷萃取、单层硅胶净化、正己烷洗脱、旋蒸浓缩后定容至100 μL,采用GC-ECD分析。结果表明,PBDEs各单体的加标回收率为63.6%~110.3%,相对标准偏差(RSD)为1.7%~15.5%(n=5);十溴联苯醚(BDE-209)的检出限为0.097 ng/g,其他7种单体的检出限为0.002~0.011 ng/g(信噪比为3)。该方法的准确度和精密度较高,稳定性和回收率良好,可满足沉积物中PBDEs的分析要求。利用建立的方法测定了渤海表层沉积物中PBDEs的含量,8种PBDEs总含量在1.566~6.760 ng/g之间,其中BDE-209的含量为1.461~6.438 ng/g,总体呈现出由近岸向远岸递减的趋势,表明人为活动、表层冲刷和陆地河流的输入对渤海地区PBDEs的含量有重要影响。

Determination of eight polybrominated diphenyl ethers in marine sediments by ultrasonically assisted alkaline degradation extraction and gas chromatography-electron capture detection

For determination of the eight polybrominated diphenyl ethers (PBDEs) in marine sediments based on gas chromatography-electron capture detection (GC-ECD), a rapid and effective method for simultaneous sample extraction and purification was developed, in which ultrasonically assisted alkaline hydrolysis was combined with solvent extraction. The sediment sample was processed in an ultrasonic bath in 2.00 mol/L NaOH-methanol solution for 30 min, and subsequently extracted by n-hexane. The organic phase was then separated and purified by silica column and concentrated to 100 μL for GC-ECD analysis. Under the optimized conditions, the recoveries and relative standard deviations (RSDs) for eight PBDE congeners ranged from 63.6% to 110.3% and from 1.7% to 10.5% (n=5), respectively. The limits of detection (LODs, S/N=3) ranged from 0.002 to 0.011 ng/g except for deca-brominated diphenyl ether (BDE-209), which was 0.097 ng/g. With high accuracy, good stability and adequate recovery, the established method was successfully applied to the analysis of PBDEs in the surface sediments from Bohai Sea. The concentrations of ∑₈PBDEs (sum of 2,4,4'-tribromodiphenyl ether (BDE-28), 2,2',4,4'-tetrabromodiphenyl ether (BDE-47), 2,2',4,4',5-pentabromodiphenyl ether (BDE-99), 2,2',4,4',6-pentabromodiphenyl ether (BDE100), 2,2',4,4',5,5'-hexabromodiphenyl ether (BDE-153), 2,2',4,4',5,6'-hexabromodiphenyl ether (BDE-154), 2,2',3,4,4',5',6-heptabromodiphenyl ether (BDE-183), BDE-209) and BDE-209 ranged from 1.566 to 6.760 ng/g and from 1.461 to 6.438 ng/g, respectively. A decreasing gradient of concentration was basically observed with increasing distance off the shore, indicating that anthropogenic activities, surface runoff and river inputs may be the sources of PBDEs in the sediments from Bohai Sea.