精准可靠的短链氯化石蜡分析方法的建立及应用

Short chain chlorinated paraffins (SCCPs) are commercial mixtures synthesized by chlorination of n-alkanes with carbon lengths between 10 and 13 carbon atoms. They have attracted considerable attentions and proposed as candidate POPs in the Stockholm Convention due to the potential for bioaccumulation capacities, persistence in the environment and high toxicity to aquatic organisms. The reliable analysis of SCCPs is extremely difficult owing to their complex composition containing thousands of homologues and isomers. So far, no standard analytical method applicable to routine monitoring has been established. In this study, an alternative approach for SCCP determination is based on their dechlorination and deuteration, where SCCPs can be reduced to the corresponding deuterated alkane. According to the analysis of deuterated alkanes by gas chromatography-mass spectrometry (GC-MS), the accurate quantification of SCCPs and their congeners could be achieved simultaneously. Technologies of both the online catalytically deuteration by deuterium and the offline deuteration by deuterated reductants are explored. The online/offline deuterated-carbon skeleton GC-MS methods are thus proposed, which overcome the difficulties on data reliability in the direct analysis of SCCPs. In addition, chlorinated alkanes with branched structures are synthetized as internal and recovery standards in environmental analysis, which could further ensure the accuracy of the results. The present study develops an approach for SCCP accurate analysis, which provides for further research on the environmental behaviors, bioaccumulation and toxicity of SCCPs.

短链氯化石蜡（SCCPs）是一组人工合成的碳链长度为10-13的正构烷烃氯代衍生物。SCCPs由于具有毒性、环境持久性和生物蓄积性而引起广泛关注，并在2009年被列入POPs候选清单。SCCPs组成复杂，同系物及同分异构体繁多，其准确定量分析仍然存在诸多困难，至今还没有建立标准的分析方法。本项目分别采用氘代还原剂以及氘气在催化剂作用下对SCCPs进行加氘脱氯，在氯取代的位置将其还原成氘取代，建立离线加氘还原和在线催化加氘方法。通过与气相色谱-质谱（GC-MS）联用，对生成的不同数目氘取代的烷烃进行分析，进而达到对SCCPs质量浓度和同系物分布模式同时检测的目的，建立SCCPs的在线/离线氘取代-碳骨架GC-MS方法。避免直接分析SCCPs所面临的分离定量方面的困扰，实现精确定量。针对SCCPs的环境分析，以具有支链结构的氯代烷烃作为提取内标和回收率内标，实现同步洗脱和转化，提高方法准确性。

短链氯化石蜡（SCCPs）是一组人工合成的碳链长度为10–13的正构烷烃氯代衍生物。SCCPs具有毒性、环境持久性和生物累积性而引起广泛关注，并在2009年被列为POPs候选物质。SCCPs组成复杂，同系物及同分异构体繁多，是目前分析方法最具有挑战性的环境污染物质。本项目采用氘代还原剂LiAlD4对SCCPs进行脱氯加氘，在氯取代的位置将其还原成相应取代位置的氘代烷烃，建立离线加氘还原方法。通过气相色谱-质谱联用分析生成的氘代烷烃，进而达到对SCCPs质量浓度和同系物分布同时检测的目的，并且避免了直接分析SCCPs所面临的分离定量方面的困扰，实现精确定量。针对环境和生物样品，采用具有支链结构的氯代2–甲基–壬烷和氯代2–甲基–十一烷作为提取和反应内标，建立SCCPs的内标定量方法。该方法分析SCCPs标准溶液总浓度的最大误差不超过1.26，相对标准偏差为10%以内。采用该方法分析环境和生物样品，可以检测到低氯代组分（Cl1-4），样品中低氯代组分的质量分数占总浓度的32.4%–62.4%，为以后SCCPs的环境、毒性研究等提供分析方法基础。.本项目总体进展与计划任务相符，基本完成预定考核指标，部分指标超额完成。项目取得的成果如下：（1）制备2种具有支链结构的SCCPs单碳数标样，即氯代2–甲基–壬烷和氯代2–甲基–十一烷，采用HRGC–ECNI–LRMS方法对其纯度进行分析，其纯度均大于95%。（2）制备20种碳链长度为10–13、氯化度在41.1%–69.6%之间的SCCPs单碳数标样。（3）开发SCCPs的离线加氘还原技术。（4）建立适用于环境和生物样品、商品氯化石蜡中SCCPs的分析方法，实现样品中SCCPs质量浓度和同系物组成分布的同时测定和精确定量。（5）研究氯化石蜡生产厂SCCPs和MCCPs的释放及迁移，以及室内环境SCCPs和MCCPs的污染暴露评估。（6）发表研究性论文6篇，其中SCI索引论文3篇；授权专利1项。培养博士和硕士研究生各1人。