Extension of a QuEChERS–UHPLC–QTOF-MS/MS Method for Tropane Alkaloid Determination in Maize Flour

Tropane alkaloid contamination of maize and maize-derived foods represents an important food safety concern due to the toxicity of compounds such as atropine and scopolamine and the low maximum levels established in European legislation. This study aimed to extend the scope of a previously validated QuEChERS–UHPLC–TOF-MS method from buckwheat flour to maize flour while enhancing compound confirmation through the implementation of information-dependent acquisition (IDA) tandem mass spectrometry (MS/MS). The original sample preparation procedure was maintained, including QuEChERS extraction, dispersive solid-phase clean-up, extract concentration, and matrix-matched calibration. Method performance in maize flour was evaluated following EURL guidance for extending the scope of validated methods to commodities within the same commodity group, using a blank matrix and independently fortified samples at the previously established limits of quantification (LOQs) and at three times these levels. Atropine and scopolamine were determined, and method performance was assessed in terms of selectivity, recovery, repeatability (RSDr), linearity, and matrix effects. Compound identity was confirmed using retention time, accurate precursor mass, and characteristic TOF-MS/MS product ions. Preliminary results indicate satisfactory method performance in maize flour, supporting the potential extension of the previously validated method to this matrix. Data evaluation is currently ongoing, and the final quantitative performance parameters are still being assessed. The incorporation of IDA–TOF-MS/MS also provides an additional level of structural confirmation based on accurate-mass product ions, increasing confidence in compound identification.

Acknowledgments: This work was funded by national funds through FCT under the projects bioTAbake (https://doi.org/10.54499/2024.14752.PEX) and ApTAsense (https://doi.org/10.54499/2024.13912.PEX). R.S. and S.R. thank their research fellowships within the scope of bioTAbake and ApTAsense, respectively. A.R.S.M. and R.O. thank FCT for financial support through a PhD fellowship (2023.04705.BDANA) and a Tenure contract (2023.12090.TENURE.027), respectively.