Determination of Pyrrolizidine Alkaloids and Their N‑Oxides in Bee Pollen by Accelerated Solvent Extraction Followed by Magnetic Covalent Organic Framework‐Based Offline Purification and Ultra‐High‐Performance Liquid Chromatography‐Tandem Mass Spectrometry

ABSTRACT Pyrrolizidine alkaloids (PAs) and their N‐oxides (PANOs) are naturally occurring toxic plant metabolites that have attracted widespread attention due to their potential food safety hazards. In this study, an efficient analytical method for determining PAs/PANOs in bee pollen was established by combining accelerated solvent extraction (ASE) with ultra‐high performance liquid chromatography‐tandem mass spectrometry (UHPLC‐MS/MS). A magnetic covalent organic framework material (Fe 3 O 4 @COF‐TAPB‐TFP) was synthesized and used as an adsorbent for offline purification to reduce matrix interference and improve detection sensitivity. Under optimal conditions, the method showed excellent linearity ( R 2 ≥ 0.99) in the range of 1–200 µg·L − 1 , with recoveries of 70.1%–95.6% for spiked blank samples at three levels (10, 50, and 100 µg·kg − 1 ), relative standard deviations below 15%, and limits of quantification of 1.2–9.9 µg·kg − 1 . This method was successfully applied to the analysis of local market bee pollen samples, with detected PAs/PANOs levels ranging from 25.6 to 178.6 µg·kg − 1 . Overall, the Fe 3 O 4 @COF‐TAPB‐TP‐assisted ASE‐UHPLC‐MS/MS method provides an accurate, rapid, highly automated, and high‐throughput platform for monitoring PAs/PANOs contamination in food products.