A new design of a flow-through coaxial electromembrane extraction (EME) probe that can be on-line coupled with CE instrument is described and tested. The supporting base of the probe is a PDMS microchip with T-shaped channels into which two coaxially arranged capillaries for inlet and outlet solutions are inserted. The extraction part of the probe is a porous polypropylene hollow fiber, sealed at one end and modified with nitrophenyloctyl ether (NPOE) extraction fluid. The internal volume of the extraction probe is 1.1 μL. The EME probe was tested on laboratory samples and methadone was extracted into 3.0 M AcOH as acceptor. The concentration dependence was linear in the range of 0.1–1.0 μg mL at EME 300 s/150 V and in the range of 0.5–10.0 μg mL at EME 100 s/150 V. The enrichment factor was greater than 30 and the LOD was 0.21 μg mL. The EME of methadone in clinical samples showed a linear concentration dependence in human urine and a nonlinear concentration dependence in serum. The distribution of methadone in each phase of the extraction system and the effect of extraction membrane thickness on the enrichment factor were studied. The EME probe can be applied repeatedly. The supporting base of EME probe and flow gating interface (FGI) are realized by a microfluidic PDMS microchips cast in the laboratory without the use of lithography. A supporting PDMS chip with coaxially arranged capillaries and extraction membrane forms a compact analytical instrument. The entire EME/CE analysis process is performed on a laboratory-made instrument and automated by LabView.

中文翻译：

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一种新型同轴流通探针，用于从临床样本中在线电膜提取美沙酮，并结合毛细管电泳

描述并测试了一种可与 CE 仪器在线耦合的流通式同轴电膜萃取 (EME) 探针的新设计。探针的支撑底座是具有 T 形通道的 PDMS 微芯片，其中插入两个同轴排列的毛细管，用于入口和出口溶液。探针的萃取部分是一根多孔聚丙烯中空纤维，一端密封，并用硝基苯辛基醚（NPOE）萃取液进行改性。提取探针的内部体积为1.1 μL。 EME 探针在实验室样品上进行了测试，并将美沙酮提取到 3.0 M AcOH 中作为受体。在 EME 300 s/150 V 时，浓度依赖性在 0.1–1.0 μg/mL 范围内，在 EME 100 s/150 V 时，在 0.5–10.0 μg/mL 范围内呈线性。富集因子大于 30，LOD 为0.21 微克毫升。临床样品中美沙酮的 EME 在人尿液中表现出线性浓度依赖性，在血清中表现出非线性浓度依赖性。研究了美沙酮在萃取系统各相中的分布以及萃取膜厚度对富集因子的影响。 EME 探头可以重复应用。 EME探针的支撑底座和流门接口（FGI）是通过实验室铸造的微流控PDMS微芯片实现的，无需使用光刻。具有同轴排列的毛细管和萃取膜的配套PDMS芯片构成了紧凑的分析仪器。整个 EME/CE 分析过程在实验室制造的仪器上执行，并由 LabView 实现自动化。