Shih Hou-Kuang, Shu Ting-Yun, Ponnusamy Vinoth Kumar, Jen Jen-Fon
Department of Chemistry, National Chung-Hsing University, Taichung 402, Taiwan.
Department of Chemistry, National Chung-Hsing University, Taichung 402, Taiwan; CME Food Testing Laboratory, Chi Mei Entech Co. & Ltd., No. 5, 32rd Road, Industrial Park, Taichung 408, Taiwan.
Anal Chim Acta. 2015 Jan 7;854:70-7. doi: 10.1016/j.aca.2014.11.021. Epub 2014 Nov 20.
In this study, a novel fatty-acid-based in-tube dispersive liquid-liquid microextraction (FA-IT-DLLME) technique is proposed for the first time and is developed as a simple, rapid and eco-friendly sample extraction method for the determination of alkylphenols in aqueous samples using high-performance liquid chromatography-ultraviolet detection (HPLC-UV). In this extraction method, medium-chain saturated fatty acids were investigated as a pH-dependent phase because they acted as either anionic surfactants or neutral extraction solvents based on the acid-base reaction caused solely by the adjustment of the pH of the solution. A specially designed home-made glass extraction tube with a built-in scaled capillary tube was utilized as the phase-separation device for the FA-IT-DLLME to collect and measure the separated extractant phase for analysis. Nonylphenol (NP) and 4-tert-octylphenol (4-tOP) were chosen as model analytes. The parameters influencing the FA-IT-DLLME were thoroughly investigated and optimized. Under the optimal conditions, the detector responses of NP and 4-tOP were linear in the concentration ranges of 5-4000 μg L(-1), with correlation coefficients of 0.9990 and 0.9996 for NP and 4-tOP, respectively. The limits of detection based on a signal-to-noise ratio of 3 were 0.7 and 0.5 μg L(-1), and the enrichment factors were 195 and 143 for NP and 4-tOP, respectively. The applicability of the developed method was demonstrated for the analysis of alkylphenols in environmental wastewater samples, and the recoveries ranged from 92.9 to 107.1%. The extraction process required less than 4 min and utilized only acids, alkalis, and fatty acids to achieve the extraction. The results demonstrated that the presented FA-IT-DLLME approach is highly cost-effective, simple, rapid and environmentally friendly in its sample preparation.
在本研究中，首次提出了一种基于脂肪酸的管内分散液液微萃取（FA-IT-DLLME）技术，并将其开发为一种简单、快速且环保的样品萃取方法，用于使用高效液相色谱-紫外检测（HPLC-UV）测定水样中的烷基酚。在这种萃取方法中，中链饱和脂肪酸被研究作为一种pH依赖相，因为基于仅通过调节溶液pH引起的酸碱反应，它们可作为阴离子表面活性剂或中性萃取溶剂。一个特别设计的带有内置刻度毛细管的自制玻璃萃取管被用作FA-IT-DLLME的相分离装置，以收集和测量分离出的萃取剂相用于分析。选择壬基酚（NP）和4-叔辛基酚（4-tOP）作为模型分析物。对影响FA-IT-DLLME的参数进行了全面研究和优化。在最佳条件下，NP和4-tOP的检测器响应在5-4000 μg L(-1)浓度范围内呈线性，NP和4-tOP的相关系数分别为0.9990和0.9996。基于3倍信噪比的检测限分别为0.7和0.5 μg L(-1)，NP和4-tOP的富集因子分别为195和143。所开发方法在环境废水样品中烷基酚分析的适用性得到了验证，回收率在92.9%至107.1%之间。萃取过程所需时间不到4分钟，仅使用酸、碱和脂肪酸来实现萃取。结果表明，所提出的FA-IT-DLLME方法在样品制备方面具有高度的成本效益、简单、快速且环保。
