Separation and enrichment of active components in Toddalia asiatica (L.) Lam.by carboxylated chitosan-modified magnetic metal-organic frameworks

Designing adsorbents with high sensitivity, superior adsorption capacity, molecular specificity, and batch-to-batch reproducibility remains a significant challenge in separation science. For the first time, we synthesized a functionalized magnetic metal-organic framework (Fe₃O₄@SiO₂@MIL-101@CLCS), to adsorb magnoflorine, hesperidin, nitidine chloride, and chelerythrine from Toddalia asiatica (L.) Lam via electrostatic interactions and π-π stacking. In order to systematically analyze the target components, this study established a magnetic solid-phase extraction coupled with high-performance liquid chromatography-diode array detection (MSPE-HPLC-DAD) method, and comprehensively optimized the extraction and elution conditions. After optimization, the adsorption rates of Fe₃O₄@SiO₂@MIL-101@CLCS on the above four active ingredients were ranged from 52.52% to 82.43%, and the elution rates were all higher than 96.40%. The adsorbent retained good adsorption capacity after 5 reuse cycles and had excellent recyclability. The method demonstrated excellent linearity (r² ≥ 0.999), with a limit of detection (LODs) of 0.17–0.92 μg/mL and a limit of quantification (LOQs) of 0.30–1.65 μg/mL, confirming high accuracy and precision. This approach not only enhances analytical efficiency in traditional Chinese medicine studies but also expands the potential of magnetic solid-phase extraction for natural product research.