Screening of Organohalogenated Toxicants in Breast Milk via GCxGC/TOF MS

母乳中存在的环境毒物是一个重要的问题，因为这些化学品对母乳喂养的婴儿的潜在健康影响。亲脂性有毒物质主要集中在高脂肪母乳中，其中包括几种不同类别的合成有机污染物，如多氯联苯（PCB）、多氯二苯并二恶英（PCDD）、多氯二苯并呋喃（PCDF）、多溴二苯醚（PBDE）和持久性农药。母乳喂养的婴儿体内这些有毒物质的负担比成人高出一个数量级以上，成人体内这些有毒物质的水平升高与生殖、行为和中枢神经系统的几种疾病有关。环境科学家继续努力测量母乳中的有毒物质，这是确定这些化学品对婴儿健康的真正贡献的一个重要因素。有必要制定新的分析筛选战略，以监测已知环境污染物的水平，并确定 母乳中的其他有毒物质。目前的筛选方法采用耗时的样品提取方案，并且样品的分析仅限于已知毒物的列表，因此不能检测新的或未知的污染物。该项目旨在开发一种基于搅拌棒吸附萃取（SBSE）和综合二维气相色谱/飞行时间质谱（GCxGC/TOF MS）的新兴技术的改进方法。 具体目标是：（1）开发基于搅拌棒吸附萃取（SBSE）技术的高通量样品制备方案;（2）开发基于综合二维气相色谱/飞行时间质谱（GCxGC/TOF MS）新兴技术的高性能样品分析方案。GCxGC/TOF MS的主要优势是比传统GC更高的分辨率、分析通量和灵敏度;以及（3）通过试点研究验证新方法，该研究将测试GCxGC/TOF MS方法与当前最先进技术相比的总体选择性、灵敏度和分析通量。

The presence of environmental toxicants in human breast milk is an important concern because of the potential health effects of these chemicals to the breast-fed infant. Lipophilic toxicants are preferentially concentrated in high-fat breast milk, and they include several different classes of synthetic organic pollutants such as polychlorinated biphenyls (PCBs), polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs), polybrominated diphenylethers (PBDEs) and persistent pesticides. The body burden of these toxicants in breast-fed infants is more than an order of magnitude higher than it is in adults, and elevated levels in adults have been linked to several disorders of the reproductive, behavioral, and central nervous systems. The continued efforts of environmental scientists to measure toxicants in breast milk are an important factor in the determination of the true contribution of these chemicals to the health of the infant population. There is a need to develop new analytical screening strategies that will monitor the levels of known environmental pollutants as well as identify additional toxicants in breast milk. Current screening methods employ sample extraction protocols that are time-consuming, and the analysis of samples is limited to the list of known toxicants and therefore not capable of detecting new or unknown contaminants. This project is intended to develop an improved method based on the combined emerging technologies of stir bar sorptive extraction (SBSE) and comprehensive two-dimensional gas chromatography/time-of-flight mass spectrometry (GCxGC/TOF MS). The specific aims are to: (1) develop a high-throughput sample preparation protocol based on the stir-bar sorptive extraction (SBSE) technique; (2) develop a high-performance sample analysis protocol based on the emerging technology of comprehensive two-dimensional gas chromatography/time-of-flight mass spectrometry (GCxGC/TOF MS). The key advantages of GCxGC/TOF MS are enhanced resolution power, analytical throughput and sensitivity over conventional GC; and (3) Validate the new method through a pilot study that will test the overall selectivity, sensitivity and analytical throughput of the GCxGC/TOF MS method when compared to the current state-of-the-art.