基于全二维气相色谱-飞行时间质谱(GC×GC-TOFMS)法溯源溪流水体中有机污染物的来源研究

Traceability of organic pollution sources in stream water using two-dimensional gas chromatography-time-of-flight mass spectrometry(GC×GC-TOFMS)

城市溪流水资源存在水体污染程度较高、污染来源复杂等问题,导致污染物溯源难,污染治理难度大.本研究以厦门某溪流为研究对象,利用全二维气相色谱-飞行时间质谱联用技术(GC×GC-TOFMS)对选定的5个样点进行了有机物的非靶向分析(其中,X1~X4代表支流,X5代表主干流).通过结合受体模型、相似度算法和非负最小二乘法,对下游干流的有机污染物进行了溯源分析.结果显示:5个点位分别检出有机物88、110、123、64、103种,主要为烷烃类、醇类和其他氮氧化合物等有机污染物. 4个上游支流点位(X1~X4)与干流水体(X5)之间的相似度分别为0.46、0.48、0.41、0.32.非负最小二乘法计算出的各支流点位对干流水体污染贡献度分别为1%、43.3%、30.1%、23.2%,二者溯源结果都表明下游干流水体的污染主要来源于支流X2.全二维气相色谱-飞行时间质谱联用技术在鉴定水中未知有机污染物方面具有显著优势,结合数学模型,为有机污染物的溯源提供了有力的技术支撑.

Urban stream water resources encounter challenges,including complex sources of pollution and high levels of water pollution.These issues make it difficult to identify pollutant sources and regulate contamination.In this study,a specific stream in Xiamen was chosen as the research object,and five sampling sites(X1~X4 are tributary streams,and X5 is the trunk stream)were selected for analysis using a two-dimensional gas chromatography-time-of-flight mass spectrometry(GC×GC-TOFMS)with non-targeted analysis.The source of contaminants in the trunk stream at downstream was examined by integrating the receptor model,similarity algorithm,and non-negative least squares approach.The results revealed the presence of 88,110,123,64,and 103 organic compounds at the five locations,primarily including alkanes,alcohols,and other nitrogen and oxygen compounds.The similarity between the each points of the tributary streams(X1~X4)and the trunk stream(X5)was found to be 0.46,0.48,0.41,and 0.32,respectively.According to the non-negative least square method,the contribution of each tributary point to the trunk stream was up to 1%,43.3%,30.1%,and 23.2%.According to the traceability results from both,the tributary X2 is primarily to blame for the contamination of the trunk stream water(X5).The two-dimensional gas chromatography-time-of-flight mass spectrometry has great advantages in the identification of unknown organic pollutants in water,and combined with mathematical models can provide good support for the traceability of organic pollutants.