Two sample preparation methods were developed (graphitised carbon and C18 solid phase extraction clean-up) and validated in house using liquid chromatography and tandem mass spectrometry (MS/MS) for the determination of 30 pyrrolizidine alkaloids (PAs) in salads, herbs, tea, herbals teas as well as tea infusion and ice-tea beverages. Total PAs concentration of samples purchased on the Belgian market varied greatly with matrix type ranging from <LOD to 187151 ng/g for dry samples, while for infusions and ice-tea beverages the highest PAs concentration was 2106 ng/mL. Surprisingly high PAs concentrations were detected in herbs and spices mixes. The infusion study indicated a transfer rate between 16 and 28% (except for monocrotaline) which highlights the overestimation of PAs concentrations in infusions when derived from a dilution factor (transfer rate of 100%) to the measured concentrations of the dry tea sample.
Keywords: Herbal infusion; Pyrrolizidine alkaloids; Salads; Spices; Teas; Transfer rate; UHPLC-MS/MS.
Copyright © 2018 Elsevier Ltd. All rights reserved.