Straightforward Determination of Pyrrolizidine Alkaloids in Honey through Simplified Methanol Extraction (QuPPE) and LC-MS/MS Modes

Alexandra Sixto; Silvina Niell; Horacio Heinzen

doi:10.1021/acsomega.9b03538

Straightforward Determination of Pyrrolizidine Alkaloids in Honey through Simplified Methanol Extraction (QuPPE) and LC-MS/MS Modes

ACS Omega. 2019 Dec 18;4(27):22632-22637. doi: 10.1021/acsomega.9b03538. eCollection 2019 Dec 31.

Authors

Alexandra Sixto¹, Silvina Niell², Horacio Heinzen¹

Affiliations

¹ Facultad de Química, Departamento Estrella Campos, Química Analítica and Facultad de Química, Departamento de Química Orgánica, Grupo de Análisis de Compuestos Traza, Cátedra de Farmacognosia y Productos Naturales, Universidad de la República, 11800 Montevideo, Uruguay.
² CENUR Litoral Norte, PDU Abordaje holístico al impacto de agroquímicos sobre alimentos y ambiente, Grupo de Análisis de Compuestos Traza, Universidad de la República, 60000 Paysandú, Uruguay.

Abstract

Contamination of honey with toxic pyrrolizidine alkaloids (PAs) and their N-oxides (PANOs) was assessed by dilution with acidic methanol and analysis through liquid chromatography (LC) coupled with tandem mass spectrometry (MS/MS) in three different modes. The hybrid linear trap/triple quadrupole (LC-QTRAP) instrument was used in precursor ion scan (PIS), enhanced product ion scan (EPI), and multiple reaction monitoring (MRM) mode. The parent ions from ions at m/z 120 or 138 amus, characteristic of all the toxic PAs and PANOs in the sample were first scanned by PIS. Then, the presence of each contaminant at specific retention times through its MS² spectrum was confirmed by EPI. Finally, they were quantified in the MRM mode. The method was validated: recoveries 86-111%, relative standard deviation (RSD) <20%, at 20 and 40 μg/kg, except retrorsine, which showed a RSD of 30% at 20 μg/kg. Honey samples were analyzed and five of them showed levels of 40 μg/kg for the sum (PAs + PANOs). This approach allows the simultaneous determination of PAs and PANOs in honey, even if their chemical standards are not available.