Department of Public Health, College of Health Science, Kaohsiung Medical University, Kaohsiung 807, Taiwan.
J Chromatogr A. 2013 Jan 4;1271(1):41-9. doi: 10.1016/j.chroma.2012.11.039. Epub 2012 Nov 23.
In this study we on-line coupled hollow fiber liquid-liquid-liquid microextraction (HF-LLLME), assisted by an ultrasonic probe, with high-performance liquid chromatography (HPLC). In this approach, the target analytes - 2-chlorophenol (2-CP), 3-chlorophenol (3-CP), 2,6-dichlorophenol (2,6-DCP), and 3,4-dichlorophenol (3,4-DCP) - were extracted into a hollow fiber (HF) supported liquid membrane (SLM) and then back-extracted into the acceptor solution in the lumen of the HF. Next, the acceptor solution was withdrawn on-line into the HPLC sample loop connected to the HF and then injected directly into the HPLC system for analysis. We found that the chlorophenols (CPs) could diffuse quickly through two sequential extraction interfaces - the donor phase - SLM and the SLM - acceptor phase - under the assistance of an ultrasonic probe. Ultrasonication provided effective mixing of the extracted boundary layers with the bulk of the sample and it increased the driving forces for mass transfer, thereby enhancing the extraction kinetics and leading to rapid enrichment of the target analytes. We studied the effects of various parameters on the extraction efficiency, viz. the nature of the SLM and acceptor phase, the compositions of the donor and acceptor phases, the fiber length, the stirring rate, the ion strength, the sample temperature, the sonication conditions, and the perfusion flow rate. This on-line extraction method exhibited linearity (r(2)≥0.998), sensitivity (limits of detection: 0.03-0.05 μg L(-1)), and precision (RSD%≤4.8), allowing the sensitive, simple, and rapid determination of CPs in aqueous solutions and water samples with a sampling time of just 2 min.
在这项研究中，我们在线耦合了中空纤维液 - 液 - 液微萃取（HF-LLLME），并辅以超声探头，与高效液相色谱（HPLC）联用。在这种方法中，目标分析物 - 2-氯苯酚（2-CP）、3-氯苯酚（3-CP）、2,6-二氯苯酚（2,6-DCP）和 3,4-二氯苯酚（3,4-DCP） - 被萃取到中空纤维（HF）支撑的液膜（SLM）中，然后反萃取到 HF 内腔中的接受溶液中。接下来，将接受溶液在线抽取到与 HF 相连的 HPLC 样品环中，然后直接注入到 HPLC 系统中进行分析。我们发现，在超声探头的辅助下，氯苯酚（CPs）可以快速通过两个连续的萃取界面 - 供体相 - SLM 和 SLM - 接受体相 - 进行扩散。超声处理有效地混合了萃取边界层与样品的主体，增加了传质驱动力，从而增强了萃取动力学，导致目标分析物的快速富集。我们研究了各种参数对萃取效率的影响，即 SLM 和接受相的性质、供体相和接受相的组成、纤维长度、搅拌速度、离子强度、样品温度、超声条件和灌注流速。这种在线萃取方法表现出线性（r(2)≥0.998）、灵敏度（检测限：0.03-0.05 μg L(-1)）和精密度（RSD%≤4.8），允许在水溶液和水样中灵敏、简单、快速地测定 CPs，采样时间仅为 2 分钟。
