Simultaneous method validation and surveillance of pyrrolizidine alkaloids and their N-oxides in some medicinal...

Pyrrolizidine alkaloids (PAs) are naturally occurring plant toxins with hepatotoxic, genotoxic, and potentially carcinogenic properties, become an important food safety concern, prompting regulatory attention from the EU and the European Food Safety Authority. In this study, a reliable analytical method was developed and validated for the simultaneous determination of 28 compounds in medicinal plants and herbal teas. The method employs QuEChERS extraction and LC-MS/MS. Validation results demonstrated satisfactory performance, with recoveries ranging from 70 to 120% under repeatability and reproducibility conditions and precision (RSDs) ≤20%. The expanded uncertainty was ±38% (at k = 2), calculated in accordance with SANTE/11312/2021 v2026 guidelines. Limits of quantification were established at 0.01 mg/kg for all analytes across the tested matrices. Calibration curves showed good linearity (R² ≥ 0.99) within 0.0001-0.1 μg/mL. Method reliability was further confirmed through successful FAPAS proficiency testing, with all z-scores <2 except three compounds having questionable z-scores. The validated method was successfully applied to 182 commercial herbal plant and tea samples collected from Egyptian markets during 2023-2026 to assess PA and PANO contamination. The survey provides crucial baseline data on the occurrence of these alkaloids in the region, supporting ongoing food safety monitoring efforts.