Identification and quantification of α- and β-amanitin in wild mushrooms by HPLC-UV-EC and HPLC-DAD-MS detection

Abstract

Amatoxins are a group of highly toxic peptides, which include α- and β-amanitin, found in several species of mushrooms (e.g. Amanita phalloides). Due to their high hepatotoxicity, they account for most deaths occurring after mushrooms ingestion. The determination of α- and β-amanitin content in wild mushrooms is invaluable for treating cases involving poisoning. In the present study, we have developed and validated an analytical method based on high-performance liquid chromatography, with in-line ultraviolet and electrochemical detection (HPLC-UV-EC), for the rapid quantification of α- and β-amanitin in wild mushroom samples collected from the Inner Center of Portugal. A reproducible and simple solid-phase extraction (SPE) using OASIS®PRIME HLB cartridges was used for sample pre-treatment, followed by chromatographic separation based on the RP-C18 column. The UV and EC chromatograms of α- and β-amanitin were recorded at 305 nm and +0.600 V vs Ag/AgCl, respectively. The linear quantification for both amanitins was in the range of 0.5–20.0 μg mL−1 (R2 > 0.999). The LOD, calculated based on the calibration curve, was similar for UV and EC detection (0.12-0.33 μg mL−1). Intra-day and inter-day precision were less than 13%, and the recovery ratios ranged from 89% to 117%. Nine Amanita species and five edible mushrooms were analysed by HPLC-UV-EC, and HPLC-DAD-MS confirmed the identification of amatoxins. We find high α- and β-amanitin content in A. phalloides and not in the other species analysed. In sum, the developed and validated method provides a simple and fast analysis of α- and β-amanitins contents in wild mushrooms and is suitable for screening and routine assessment of mushroom intoxication.