Simultaneous screening and quantitation of 101 alkaloids in food matrices by dSPE-UHPLC-HRMS

Alkaloids, widely distributed in agricultural crops and food systems, exhibit dual roles: beneficial bioactivities (e.g. berberine) and potential toxicity (e.g. pyrrolizidine alkaloids). Current analytical approaches generally target limited compound categories, lacking comprehensive detection capabilities for structurally diverse alkaloids in agricultural commodities and processed foods. Thus, this study develops a dispersive solid-phase extraction (dSPE) coupled with ultrahigh-performance liquid chromatography-high-resolution mass spectrometry (UHPLC-HRMS) method for the simultaneous screening and quantitation of 101 alkaloids across 12 categories in complex food matrices.

A comprehensive alkaloid database was established, including compound names, precursor ions, product ions, and retention times. The method employed methanol extraction, dSPE purification with 100 mg of ethylenediamine-N-propylsilyl, 50 mg of octadecylsilyl, and 30 mg of anhydrous MgSO₄, and reconstitution in 50% methanol containing 0.1% formic acid after nitrogen evaporation. The approach showed good applicability to complex matrices, with screening detection limits of 2-10 μg kg^-1 and quantification limits of 4-20 μg kg^-1. Satisfactory recoveries (51.02-119.48%) and excellent precision (relative standard deviations <20%) were achieved at low, medium, and high spiked levels. Analysis of 121 market samples revealed alkaloid presence in >25% of specimens, including cytotoxic l-abrine and hepatotoxic lycopsamine. Novel evidence of food contamination and adulteration was revealed, including tea alkaloids in aged dried tangerine peel (Chenpi) and medicinal plant alkaloids in Sichuan pepper.

The established dSPE-UHPLC-HRMS approach is reliable and practical. It can serve as a powerful tool for food regulatory monitoring, food adulteration detection, and public dietary risk assessment. © 2026 Society of Chemical Industry.