A green analytical method for the simultaneous determination of 30 tropane and pyrrolizidine alkaloids and their N-oxides in teas and herbs for infusions by LC-Q-Orbitrap HRMS.

A green analytical method for the simultaneous determination of 30 tropane and pyrrolizidine alkaloids and their N-oxides in dried teas and herbs for infusions has been developed and validated. The proposed method is based on QuEChERS procedure followed by LC-Q-Orbitrap HRMS analysis. The method includes a first screening analysis to assess the presence of alkaloids, followed by the quantification of suspected positive samples (cut-off level, 0.2-2.6 µg kg-1). The method was validated in five different tea and herb matrices showing satisfactory linearity (R2 ≥0.99), method limits of quantification (5 µg kg-1), accuracy (87-111 %), and precision (RSD <20 %). The greenness of the proposed method was evaluated according to the Analytical Eco-Scale, showing that it could be considered an excellent green analysis. Finally, eleven commercial field samples of tea and herbs for infusions, including rooibos, chamomile, red tea, black tea, green tea, white tea, linden, horsetail, and one infusion containing a mixture of herbs, were analyzed and the obtained results demonstrated that they were in compliance with the current European regulations regarding the studied substances.