College of Pharmacy, Dali University, Dali, Yunnan, 671000, China.
Key Laboratory of Green Chemistry & Technology of MOE, College of Chemistry, Sichuan University, Chengdu, Sichuan, 610064, China.
Anal Chim Acta. 2024 Feb 15;1290:342197. doi: 10.1016/j.aca.2023.342197. Epub 2024 Jan 5.
Pretreatment techniques should be introduced before metal ion determination because there is very low content of heavy metals in Chinese medicinal plants and environmental samples. Magnetic dispersive micro solid phase extraction (MDMSPE) has been widely used for the separation and adsorption of heavy metal pollutants in medicinal plants and environmental samples. However, the majority of MDMSPE adsorbents have certain drawbacks, including low selectivity, poor anti-interference ability, and small adsorption capacity. Therefore, modifying currently available adsorption materials has gained attention in research.
In this study, a novel adsorbent MCOF-DES based on a magnetic covalent organic framework (MCOF) modified by a new deep eutectic solvent (DES) was synthesized for the first time and used as an adsorbent of MDMSPE. The MDMSPE was combined with inductively coupled plasma optical emission spectrometry (ICP-OES) for selective separation, enrichment, and accurate determination of trace copper ion (Cu) in medicinal plants and environmental samples. Various characterization results show the successful preparation of new MCOF-DES. Under the optimal conditions, the enrichment factor (EF) of Cu was 30, the limit of detection (LOD) was 0.16 μg L, and the limit of quantitation (LOQ) was 0.54 μg L. The results for the determination of Cu were highly consistent with those of inductively coupled plasma mass spectrometry (ICP-MS), which verified the accuracy and reliability of the method.
The established method based on a new adsorption material MCOF-DES has achieved the selective separation and determination of trace Cu in medicinal and edible homologous medicinal materials (Phyllanthus emblica Linn.) and environmental samples (soil and water), which provides a promising, selective, and sensitive approach for the determination of trace Cu in other real samples.
在测定金属离子之前，应引入预处理技术，因为中药和环境样品中的重金属含量非常低。磁性分散微固相萃取（MDMSPE）已广泛用于中药和环境样品中重金属污染物的分离和吸附。然而，大多数 MDMSPE 吸附剂都存在一定的缺点，包括选择性低、抗干扰能力差、吸附容量小等。因此，对现有吸附材料进行改性引起了研究人员的关注。
本研究首次合成了一种基于磁性共价有机框架（MCOF）的新型吸附剂 MCOF-DES，并用一种新的深共晶溶剂（DES）对其进行修饰，作为 MDMSPE 的吸附剂。将 MDMSPE 与电感耦合等离子体发射光谱法（ICP-OES）相结合，用于选择性分离、富集和准确测定中药和环境样品中的痕量铜离子（Cu）。各种表征结果表明成功制备了新型 MCOF-DES。在最佳条件下，Cu 的富集因子（EF）为 30，检测限（LOD）为 0.16μg/L，定量限（LOQ）为 0.54μg/L。Cu 测定结果与电感耦合等离子体质谱法（ICP-MS）高度一致，验证了该方法的准确性和可靠性。
基于新型吸附材料 MCOF-DES 建立的方法实现了药用同源药材（余甘子）和环境样品（土壤和水）中痕量 Cu 的选择性分离和测定，为其他实际样品中痕量 Cu 的测定提供了一种有前景、选择性强、灵敏度高的方法。
