Two-step extraction for the evaluation of metal–organic framework impregnated materials

IF 1.8 4区化学 Q3 CHEMISTRY, ANALYTICAL Analytical Sciences Pub Date : 2024-05-29 DOI:10.1007/s44211-024-00608-5

Mizuki Mukai, Reetu Rani, Nao Iwanaga, Kentaro Saeki, Kei Toda, Shin-Ichi Ohira

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Abstract

Metal–organic frameworks (MOFs) are widely used for gas adsorption, separation, and sensing materials. In most cases, MOFs are not used in their crystal form but as impregnated materials because the fine crystals result in high-pressure drops. One key characteristic of MOF-impregnated materials is the amount of MOF in the material. This is evaluated using the wet digestion method; however, it is limited to determining only the metal content. Moreover, some metal, denoted as free metal, will not react with ligands to form MOFs. Additionally, it is crucial to determine the ligand amount, which cannot be determined using wet digestion. In the present study, a two-step extraction method for copper (II) benzene-1,3,5-tricarboxylate (Cu-BTC MOF) impregnated materials was developed to determine the MOF formed and free metals and ligands. Various solvents were applied to evaluate the extraction efficiencies. The results led to the selection of ethanol (EtOH) for extracting free Cu²⁺ and BTC, while 0.3 M HNO₃ was chosen to extract MOF-formed Cu²⁺ and BTC. The MOF-impregnated sample material was first extracted using EtOH and then 0.3 M HNO₃. The Cu²⁺ and BTC in the obtained extract solutions, as well as EtOH and HNO₃, were analyzed using flame atomic absorption spectroscopy and high-performance liquid chromatography, respectively. In standard addition tests, free and MOF-formed Cu²⁺ and BTC were quantitatively extracted from MOF-impregnated materials. The developed two-step analysis method was successfully applied to Cu-BTC-impregnated materials used in gas sensing.

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评估金属有机框架浸渍材料的两步萃取法。

金属有机框架（MOFs）被广泛用于气体吸附、分离和传感材料。在大多数情况下，MOF 并不是以晶体形式使用，而是作为浸渍材料使用，因为细小的晶体会导致高压滴。MOF 浸渍材料的一个关键特征是材料中的 MOF 含量。可使用湿消化法进行评估，但这种方法仅限于确定金属含量。此外，有些金属（称为游离金属）不会与配体反应形成 MOF。此外，确定配体的数量也至关重要，而湿消解法无法确定配体的数量。本研究开发了一种浸渍材料苯-1,3,5-三羧酸铜（II）（Cu-BTC MOF）的两步萃取法，以确定所形成的 MOF 以及游离金属和配体。应用各种溶剂对萃取效率进行了评估。结果表明，乙醇（EtOH）可用于萃取游离的 Cu2+ 和 BTC，而 0.3 M HNO3 可用于萃取 MOF 形成的 Cu2+ 和 BTC。首先用乙醇萃取 MOF 浸渍的样品材料，然后用 0.3 M HNO3 萃取。用火焰原子吸收光谱和高效液相色谱法分别分析了萃取液、EtOH 和 HNO3 中的 Cu2+ 和 BTC。在标准添加试验中，从 MOF 浸渍材料中定量提取了游离的和 MOF 形成的 Cu2+ 和 BTC。所开发的两步分析法成功地应用于气体传感中的 Cu-BTC 浸渍材料。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

Analytical Sciences 化学-分析化学

CiteScore

2.90

自引率

18.80%

发文量

232

审稿时长

1 months

期刊介绍： Analytical Sciences is an international journal published monthly by The Japan Society for Analytical Chemistry. The journal publishes papers on all aspects of the theory and practice of analytical sciences, including fundamental and applied, inorganic and organic, wet chemical and instrumental methods. This publication is supported in part by the Grant-in-Aid for Publication of Scientific Research Result of the Japanese Ministry of Education, Culture, Sports, Science and Technology.