Department of Chemistry, University of Pretoria, Private Bag X20, Hatfield, 0028, Pretoria, South Africa.
Department of Chemistry, University of Pretoria, Private Bag X20, Hatfield, 0028, Pretoria, South Africa.
Anal Chim Acta. 2017 Sep 1;984:107-115. doi: 10.1016/j.aca.2017.06.030. Epub 2017 Jun 22.
The presence of micropollutants in the aquatic environment is a worldwide environmental concern. The diversity of micropollutants and the low concentration levels at which they may occur in the aquatic environment have greatly complicated the analysis and detection of these chemicals. Two sorptive extraction samplers and two thermal desorption methods for the detection of micropollutants in water were compared. A low-cost, disposable, in-house made sorptive extraction sampler was compared to SBSE using a commercial Twister sorptive sampler. Both samplers consisted of polydimethylsiloxane (PDMS) as a sorptive medium to concentrate micropollutants. Direct thermal desorption of the disposable samplers in the inlet of a GC was compared to conventional thermal desorption using a commercial thermal desorber system (TDS). Comprehensive gas chromatography coupled to time-of-flight mass spectrometry (GC × GC-TOFMS) was used for compound separation and identification. Ten micropollutants, representing a range of heterogeneous compounds, were selected to evaluate the performance of the methods. The in-house constructed sampler, with its associated benefits of low-cost and disposability, gave results comparable to commercial SBSE. Direct thermal desorption of the disposable sampler in the inlet of a GC eliminated the need for expensive consumable cryogenics and total analysis time was greatly reduced as a lengthy desorption temperature programme was not required. Limits of detection for the methods ranged from 0.0010 ng L to 0.19 ng L. For most compounds, the mean (n = 3) recoveries ranged from 85% to 129% and the % relative standard deviation (% RSD) ranged from 1% to 58% with the majority of the analytes having a %RSD of less than 30%.
水中微污染物的存在是一个全球性的环境问题。微污染物的多样性和它们在水生环境中可能出现的低浓度水平极大地增加了这些化学物质的分析和检测的复杂性。比较了两种用于水中微污染物检测的吸附萃取采样器和两种热解吸方法。一种低成本、一次性、自制的吸附萃取采样器与使用商业 Twister 吸附采样器的 SBSE 进行了比较。两种采样器均由聚二甲基硅氧烷（PDMS）作为吸附剂，用于浓缩微污染物。一次性采样器在 GC 的进样口直接热解吸与使用商业热解吸器系统（TDS）进行的常规热解吸进行了比较。综合气相色谱与飞行时间质谱联用（GC×GC-TOFMS）用于化合物的分离和鉴定。选择了十种微污染物，代表了一系列不同的化合物，以评估方法的性能。与商业 SBSE 相比，具有低成本和一次性优势的自制采样器的结果相当。GC 进样口直接对一次性采样器进行热解吸，无需使用昂贵的消耗性低温制冷技术，总分析时间大大缩短，因为不需要冗长的解吸温度程序。方法的检出限范围为 0.0010ng L 至 0.19ng L。对于大多数化合物，（n=3）的平均回收率范围为 85%至 129%，相对标准偏差（%RSD）范围为 1%至 58%，大多数分析物的%RSD 小于 30%。
