溴代二恶英的全二维气相色谱分离分析方法及其在典型地区的环境行为研究

Polybrominated dibenzo-p-dioxins and dibenzofurans (PBDD/Fs) have similar structure and toxicity with chlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs), but the PBDDs/Fs have higher molecular weights, higher melting points, lower vapor pressures, lower water solubilities, and higher log Kow values, which means PBDD/Fs are easier enriched in the organism than PCDD/Fs. The analysis of PBDD/Fs is still a major challenge because of the trace amounts of PBDD/Fs in the environment and the lack of quantification standards. In this study, a new method was established to analyze PBDD/Fs and other POPs by using comprehensive two-dimensional gas chromatography. PBDD/Fs are extracted by ASE. Then, the samples were cleaned up by sulphuric acid-silica gel column, multi-layer gel column and florisil / alumina /active carbon column. The advantage of this purification column combinations is the good recovery of PBDD/Fs as well as other POPs such as PCDD/Fs, PCBs, PBDEs etc. Comprehensive two-dimensional gas chromatography (GC×GC) has a high peak capacity, resolution and sensitivity compared to1D-GC, which makes it suited to trace contaminant analysis in complex matrices. Here, GC×GC was evaluated for the separation of PBDD/Fs. The detection limit should be less than 0.01ng/g. The rapid increase in the use of brominated flame retardants has raised the level of environmental concern regarding PBDD/Fs, which are presented as low-level contaminants in some of the commercial mixtures as well as being produced upon their combustion. This study will investigate the concentrations in a typical incineration plant soil.

溴代二恶英( PBDD/Fs)与氯代二恶英( PCDD/Fs) 具有相似的结构和毒性，广泛存在于环境介质中，已引起了广泛的关注。PBDD/Fs在环境中含量极低，测定过程中易受到多溴联苯醚（PBDEs）的干扰，对其准确定性和定量仍面临极大挑战。本课题拟开展PBDD/Fs准确定性和定量研究，在样品提取净化方面，采用一次提取、多种净化柱组合的分步净化方法，实现一次样品前处理对PBDD/Fs与多种有机污染物的净化分离。利用全二维气相色谱-飞行时间质谱在分离鉴定方面的优势实现PBDD/Fs与其他有机污染物的分离，并对目标物PBDD/Fs准确定性识别及定量，检出限低于0.01ng/g。目前有关PBDD/Fs 在环境中的分布的数据还十分有限，本课题在建立方法的基础上，对典型垃圾焚烧厂土壤样品进行测定，分析研究PBDD/Fs在土壤中的污染水平。

溴代二恶英(PBDD/Fs)与氯代二恶英(PCDD/Fs) 具有相似的结构和毒性，PBDD/Fs在环境中含量极低，测定过程中易受到多溴联苯醚（PBDEs）的干扰，对其准确定性和定量仍面临极大挑战。本研究利用全二维气相色谱在分离鉴定方面的优势建立了全二维气相色谱-飞行时间质谱法（GC×GC-TOF-MS）测定土壤中PBDD/Fs的新方法。通过实验优化，以弱极性的DB-5MS 为第1根色谱柱，以中等极性的Rxi 17Sil MS 为第2根色谱柱对PBDD/Fs和其他的POPs进行分离分析，获得良好的分离效果，并对目标物PBDD/Fs准确定性识别及定量。在样品提取净化方面，采用一次提取、多层复合硅胶柱、碱性氧化铝柱、弗罗里硅土柱组合的净化方法，实现一次样品前处理对PBDD/Fs与PCBs和PBDEs等有机污染物的净化分离。所建立方法的回收率较好为76.3~106%，RSD为4.68~12.35%，回归方程的线性关系良好，相关系数大于0.997，得到PBDD/Fs的方法检出限（S/N=3）可达ng/g，尤其是四到五溴代化合物可达0.01ng/g。目前有关PBDD/Fs 在环境中的分布的数据还十分有限，本课题以一生活垃圾焚烧厂为中心，在厂区周围2.5km的范围内选取包括厂区在内的30个环境敏感点，对其土壤环境进行PBDD/Fs 测定，结果表明，厂区土壤显示最高浓度水平(300~414ng/kg, 10.2~18.9 ng TEQ/kg)，厂区周边的土壤均表现出较低的污染水平(14~177ng/kg , 0.28~8.20 ng TEQ/kg)，均没有对土壤环境造成安全威胁。样品中PBDD/Fs单体及同族物分布的特征均显示了1,2,3,4,6,7,8-HpBDF和OBDF 的主要贡献特征。对生活垃圾焚烧厂PBDD/Fs的测定分析，为后续对人体健康风险评估的研究提供技术支持及积累数据，为PBDD/Fs 的环境风险评价及污染控制与治理提供科学依据。