Department of Chemistry, Faculty of Sciences, Tarbiat Modares University, P.O. Box: 14115 175, Tehran, Iran.
Department of Chemistry, Faculty of Sciences, Tarbiat Modares University, P.O. Box: 14115 175, Tehran, Iran.
Talanta. 2021 Mar 1;224:121864. doi: 10.1016/j.talanta.2020.121864. Epub 2020 Nov 5.
In the present study, a versatile combination of electromembrane extraction (EME) with thin film solid phase microextraction (TF-SPME) was introduced using a microfluidic chip device. The device consisted of two single channels on two separate layers. The upper channel was dedicated to donor phase flow pass, while the beneath channel was used as a reservoir for stagnant acceptor solution. A slide of fluorine doped tin oxide (FTO) was accommodated in the bottom of the acceptor phase channel. A thin layer of polyaniline was electrodeposited on the FTO surface to achieve the required thin film for TF-SPME. A stainless-steel wire was embedded in the donor phase channel and another wire was also attached to the FTO surface. The channels were separated by a piece of polypropylene membrane impregnated with 1-octanol and the whole chip was fixed with bolts and nuts. The driving force for the extraction was an 8 V direct current (DC) voltage applied across the supported liquid membrane (SLM). Under the influence of the electrical field, analytes immigrated from sample towards the acceptor phase and then adsorbed on the thin film of the solid phase. Finally, the analytes were desorbed by successive movement of a desorption solvent in the acceptor phase channel followed by injection of the desorption solution to HPLC-UV. The applicability of the proposed device was demonstrated by the determination of four synthetic food dyes: Amaranth, Ponceau 4R, Allura Red, and Carmoisine, as the model analytes. The effective parameters on the efficiency of the both EME and TF-SPME were investigated. Under the optimized conditions, the microchip provided low LODs (1-10 μg L), and a wide linear dynamic range of 10-1000 μg L for all analytes. The system also offered RSD values lower than 5.5% and acceptable reusability of the thin film for multiple extractions.
在本研究中，采用微流控芯片装置，将电膜萃取（EME）与薄膜固相微萃取（TF-SPME）相结合，实现了多功能组合。该装置由两层上、下两个独立的单通道组成。上层通道用于供体相流动通过，而下层通道则作为静止接受相溶液的储液器。在接受相通道的底部容纳了一块掺氟氧化锡（FTO）薄片。在 FTO 表面电沉积一层聚苯胺，以获得所需的 TF-SPME 薄膜。在供体相通道中嵌入一根不锈钢丝，并将另一根金属丝连接到 FTO 表面。通道由一块浸渍 1-辛醇的聚丙烯膜隔开，整个芯片用螺栓和螺母固定。萃取的驱动力是施加在支撑液膜（SLM）上的 8V 直流（DC）电压。在电场的影响下，分析物从样品向接受相迁移，然后被固相的薄膜吸附。最后，通过在接受相通道中连续移动洗脱溶剂，将分析物洗脱下来，然后注入洗脱溶液到 HPLC-UV 中进行分析。通过测定四种合成食用色素（苋菜红、诱惑红 4R、诱惑红、胭脂红）作为模型分析物，验证了所提出的装置的适用性。研究了对 EME 和 TF-SPME 效率有影响的有效参数。在优化条件下，微芯片为所有分析物提供了低检出限（1-10μg/L）和 10-1000μg/L 的宽线性动态范围。该系统还提供了低于 5.5%的 RSD 值和可接受的薄膜多次萃取的可重复性。
