A new automated flow-through adsorption/desorption procedure using a multiwalled carbon nanotube immobilised mixed matrix membrane is described. The membrane consisted of 25% (w/w) multiwall carbon nanotube loading in a cellulose triacetate polymer matrix as support and was cast and embedded in a flow-through cell with a channel of an approximate length of 20 mm, a width of 2 mm, and a depth of 1.5 mm. The membrane immobilised with nanoparticles was activated using 1-octanol as a conditioning solvent. For the analyte adsorption process, 6 mL of the sample was passed through the cell at a flow rate of 0.2 mL min −1 . The entrapped target analytes were then desorbed dynamically with 60 µL of 2-propanal at a flow rate of 5 µL min −1 prior to HPLC/UV analysis. The performance of the system was demonstrated for the determination of chlorinated phenoxyacetic acid herbicides in sewage water samples. Under the optimum conditions, the linearity of this method ranged from 50 to 1000 ng mL −1 , with a correlation coefficient ( r ) ≥ 0.993 and a detection limit varying from 15 to 20 ng mL −1 . Enrichment factors of up to 55 were achieved with relative recoveries of 95–99% and precision values of 6.1–7.5%.

中文翻译：

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液相色谱前自动混合基质膜微萃取，用于测定污水样品中的氯苯氧酸除草剂

描述了一种使用多壁碳纳米管固定混合基质膜的新型自动流通吸附/解吸过程。该膜由 25% (w/w) 多壁碳纳米管负载在作为载体的三醋酸纤维素聚合物基质中组成，并被浇铸并嵌入具有大约 20 毫米长、2 毫米宽的通道的流通池中，深度为 1.5 毫米。使用 1-辛醇作为调节溶剂激活固定有纳米颗粒的膜。对于分析物吸附过程，6 mL 样品以 0.2 mL min -1 的流速通过池。然后在 HPLC/UV 分析之前，以 5 µL min -1 的流速用 60 µL 2-丙醛动态解吸捕获的目标分析物。该系统在测定污水样品中的氯化苯氧乙酸除草剂方面的性能得到了证明。在最佳条件下，该方法的线性范围为 50 至 1000 ng mL -1 ，相关系数 (r) ≥ 0.993，检出限为 15 至 20 ng mL -1 。富集因子高达 55，相对回收率为 95-99%，精密度值为 6.1-7.5%。