Department of Chemistry, Institute for Advanced Studies in Basic Sciences (IASBS), P.O. Box 45195-1159, Zanjan, Iran.
Analyst. 2018 Sep 24;143(19):4684-4698. doi: 10.1039/c8an01066h.
The main objective of this study focuses on exploration of the feasibility of Al30 polyoxocations for preparation of a novel sorbent material for a solid-phase extraction (SPE) method by selective adsorption and extraction of a class of compounds considering the type of interactions involved in the adsorption process. Accordingly, first Al30 polyoxocations were synthesized and their composite was prepared with graphene oxide (GO) nanosheets as a suitable substrate to be introduced as a SPE sorbent material. Then, the prepared composite was incorporated into polycaprolactone (PCL) nanofibers via electrospinning to present an alternative sorbent for SPE-based on a GO/Al30 nanocomposite (GO/Al30 NC) creating no need for filtering or centrifuging steps. Intercalation of Al30 polyoxocations into the GO layers and the incorporation of GO/Al30 NC into PCL nanofibers was successfully confirmed through FE-SEM, TEM, EDX, XRD, BET, TGA, IR spectroscopy, and zeta potential determination. For investigating the types of probable interactions involved in the adsorption process of different compounds on the proposed sorbents, four statin drugs, cholesterol-lowering agents with various polarity and ionization properties, were selected as model analytes. Factors affecting the extraction efficiency of dispersive SPE and immersed SPE methods using GO/Al30 NC and GO/Al30 NC-PCL nanofibers, respectively, were investigated and optimized. Under optimal conditions, acceptable analytical figures of merit were obtained for both SPE methods. A comparison of extraction efficiencies of the target drugs by the two proposed sorbents, as well as GO nanosheets and PCL nanofibers, was accomplished to study the types of interactions as well as the adsorption mechanism. The results revealed that GO/Al30 NC, having many polar and anion exchange sites caused by Al30 polyoxocations, is a good selective sorbent for acidic polar compounds which their extraction by nonpolar sorbents is not desirable. Additionally, GO/Al30 NC-PCL nanofibers exhibited extraction capability for a wide range of compounds from acidic polar to nonpolar and nonionizable ones.
本研究的主要目的是探索 Al30 多氧阳离子用于制备新型固相萃取（SPE）方法中吸附和萃取一类化合物的新型吸附材料的可行性，考虑到吸附过程中涉及的相互作用类型。因此，首先合成了 Al30 多氧阳离子，并将其与氧化石墨烯（GO）纳米片复合，作为一种合适的基质，引入作为 SPE 吸附材料。然后，通过静电纺丝将制备的复合材料掺入聚己内酯（PCL）纳米纤维中，提出了一种基于 GO/Al30 纳米复合材料（GO/Al30 NC）的 SPE 替代吸附剂，无需过滤或离心步骤。通过 FE-SEM、TEM、EDX、XRD、BET、TGA、IR 光谱和 ζ 电位测定成功证实了 Al30 多氧阳离子插入 GO 层中和 GO/Al30 NC 掺入 PCL 纳米纤维中。为了研究不同化合物在拟议吸附剂上吸附过程中可能涉及的相互作用类型，选择了四种他汀类药物，即具有不同极性和电离特性的降胆固醇药物作为模型分析物。分别考察并优化了分散固相萃取和浸入固相萃取方法中使用 GO/Al30 NC 和 GO/Al30 NC-PCL 纳米纤维的萃取效率的影响因素。在最佳条件下，两种 SPE 方法均获得了可接受的分析性能。通过比较两种拟议吸附剂以及 GO 纳米片和 PCL 纳米纤维对目标药物的萃取效率，研究了相互作用类型和吸附机制。结果表明，GO/Al30 NC 由于 Al30 多氧阳离子的存在具有许多极性和阴离子交换位点，是一种对酸性极性化合物具有良好选择性的吸附剂，对于非极性吸附剂而言，其萃取效果不理想。此外，GO/Al30 NC-PCL 纳米纤维表现出对从酸性极性到非极性和非电离化合物的广泛化合物的萃取能力。
