Determination and Chemical Profiling of Toxic Pyrrolizidine Alkaloids in Botanical Samples with UPLC–Q-TOFMS

Abstract

Pyrrolizidine alkaloids (PAs) and their N-oxides (PANOs) can cause liver toxicity and genotoxicity in humans and animals, necessitating the development of screening tools for these alkaloids. Ultra-performance liquid chromatography–electrospray ionization-quadrupole-time-of-flight mass spectrometry (UPLC–ESI–Q-TOFMS) can provide accurate precursor and fragment ion mass information (MSE mode) as well as simultaneous quantification. A method for rapidly and accurately determining nine PAs with UPLC–ESI–Q-TOF MS was developed and validated herein. Analytes were separated using a C18 column with water containing 0.1% formic acid and acetonitrile, showing high-resolution peaks within 11 min. The validation results showed excellent linearity (R2 > 0.9951), limits of detection (0.4–2.0 ng mL−1), and limits of quantification (0.6–6.0 ng mL−1). Moreover, 70 PAs, their N-oxides precursors, and characteristic fragment ions that were generated according to their chemical structure were characterized. A method for the chemical profiling of alkaloids was also proposed using the mass information obtained from the chromatograms of the tested sample. Lycopsamine, senecionine, senkirkine, and echimidine were identified in four potentially PA-containing plants and quantified by matching with authentic standards. Eight PAs and PANOs were also tentatively identified using the mass data from the previously listed alkaloids. This approach will provide a database that can be used to instantly identify alkaloids in botanical samples.