A stable core-shell metal-organic framework@covalent organic framework composite as solid-phase extraction adsorbent for selective enrichment and determination of flavonoids

Mingcai Ma; Xiaofeng Lu; Licheng Wang; Yong Guo; Hui Ding; Shuai Wang; Xiaojing Liang

doi:10.1016/j.chroma.2023.464324

A stable core-shell metal-organic framework@covalent organic framework composite as solid-phase extraction adsorbent for selective enrichment and determination of flavonoids

J Chromatogr A. 2023 Sep 27:1707:464324. doi: 10.1016/j.chroma.2023.464324. Epub 2023 Aug 23.

Authors

Mingcai Ma¹, Xiaofeng Lu², Licheng Wang², Yong Guo², Hui Ding³, Shuai Wang⁴, Xiaojing Liang⁵

Affiliations

¹ CAS Key Laboratory of Chemistry of Northwestern Plant Resources and Key Laboratory for Natural Medicine of Gansu Province, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou 730000, China; University of Chinese Academy of Sciences, Beijing 100049, China.
² CAS Key Laboratory of Chemistry of Northwestern Plant Resources and Key Laboratory for Natural Medicine of Gansu Province, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou 730000, China.
³ Key Laboratory of Pesticide and Veterinary Drug Monitoring for State Market Regulation, Lanzhou Institute for Food and Drug Control, Lanzhou 730050, China.
⁴ CAS Key Laboratory of Chemistry of Northwestern Plant Resources and Key Laboratory for Natural Medicine of Gansu Province, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou 730000, China. Electronic address: licpws@hotmail.com.
⁵ CAS Key Laboratory of Chemistry of Northwestern Plant Resources and Key Laboratory for Natural Medicine of Gansu Province, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou 730000, China. Electronic address: xjliang@licp.cas.cn.

PMID: 37634259
DOI: 10.1016/j.chroma.2023.464324

Abstract

Hydrophobization and stability is crucial for the practical application of most metal-organic frameworks (MOFs) in extraction technique. In this study, a stable core-shell MOF@COF composite (NH₂-MIL-101(Fe)@TAPB-FPBA-COF) was successfully prepared by Schiff base reaction and applied to solid-phase extraction (SPE) of hydrophobic flavonoids. Notably, the TAPB-FPBA-COF shell acts as a hydrophobic "shield", which not only improves the hydrophobicity and stability of hydrophilic NH₂-MIL-101(Fe), but also makes the extraction efficiency of flavonoids from MOF@COF composite significantly higher than that of pure NH₂-MIL-101(Fe) and TAPB-FPBA-COF. In addition, a sensitive analytical method with excellent linearities (0.1-500 ng mL^-1, R² ≥ 0.9967), low limits of detection (0.02-0.04 ng mL^-1 for water; 0.04-0.07 ng mL^-1 for grape juice; 0.06-0.08 ng mL^-1 for honey), good repeatability (intra-day/inter-day precision are 1.86-5.37%/1.82-7.79%, respectively) and only 5 mg of adsorbent per cartridge was established by optimizing the SPE process combined with high performance liquid chromatography with ultraviolet-visible detector (HPLC-UV). Meanwhile, selectivity study and comparative experiments with the commercial C18 adsorbent showed that the MOF@COF adsorbent exhibited satisfactory extraction efficiency for flavonoids due to multiple interactions such as hydrogen bonding, hydrophobic, and π-π interactions. Finally, the good recoveries in grape juice (84.5-102.5%) and honey (87.5-104.6%) samples further validated the applicability of the proposed method in complex samples.

Keywords: Core-shell structure; Flavonoids; High performance liquid chromatography; MOF@COF composite; Solid-phase extraction.

MeSH terms

Flavonoids
Metal-Organic Frameworks*
Solid Phase Extraction

Substances

MIL-101
Metal-Organic Frameworks
1,3-bis(4-amidinophenoxy)-2-(4-amidinophenoxymethyl)ethylpropane
Flavonoids