Automated and Highly Efficient Detection of Lignans in Plant-Derived Foods Based on Magnetic Solid-Phase Extraction Combined with UPLC

Lignans, a class of plant-derived polyphenolic compounds, exhibit significant bioactivities and serve as valuable functional food ingredients. However, conventional enrichment methods often suffer from inadequate selectivity and environmental incompatibility, limiting their practical application. In this study, the magnetic metal–organic framework Fe3O4@ZIF-67 was employed as an adsorbent for magnetic solid-phase extraction (MSPE). Coupled with ultra-performance liquid chromatography (UPLC), this method achieved rapid, selective, and high-efficiency enrichment of lignans—sesaminol, sesamin, and sesamolin. Method validation demonstrated excellent linearity (R2 ≥ 0.9999) over the concentration range of 0.5–100 μg/mL, acceptable recoveries (75.7–107.8%) with relative standard deviations (RSDs) ≤ 15%, and limits of detection (LODs) and limits of quantification (LOQs) in the ranges of 0.02–0.1 μg/mL and 0.09–0.25 μg/mL, respectively. Furthermore, an automated high-throughput detection system was developed through the integration of MSPE with UPLC, providing a simple and robust strategy for lignan quantification in functional food analysis.