Study of the occurrence of tropane alkaloids in animal feed using LC-HRMS

Abstract

The consumption of animal products is rapidly increasing and, therefore, the use of feedstuffs in farms is in demand in developing countries. Feed cereals represent more than 48% of total feed material and they might be contaminated by Solanaceae plants, which contain toxic metabolites such as tropane alkaloids. A wide-scope analysis of tropane alkaloids in feed, including atropine, scopolamine, tropinone, anisodamine, tropane, homatropine, tropine, littorine, physoperuvine, pseudotropine, apoatropine and aposcopolamine, has been performed using liquid chromatography coupled to an Exactive-Orbitrap analyzer. An extraction method based on pressurized liquid extraction with methanol/water/formic acid (75/25/0.4; v/v/v) as a solvent extraction, followed by a solid phase extraction step using Strata-X-C cartridges and a clean-up step with chitosan has been used. The method was fully validated and recoveries from 70 to 109% with an intraday precision lower than or equal to 15% were achieved and limits of quantification (LOQs) ranged from 5 to 25 μg kg⁻¹ for all the compounds. More than 40 samples belonging to several classes of animal feed (cow, rabbit, sheep, chicken and pig) were analysed, showing the occurrence of tropane alkaloids in 18 out of 45 samples, with concentration ranging from 5 (atropine) to 222 μg kg⁻¹ (scopolamine), highlighting the need of analytical methods for the control of TAs in animal feeds.