A simple derivatization method for simultaneous determination of four amino group-containing mushroom toxins in mushroom and urine by UPLC-MS/MS

Mushroom poisoning is becoming a serious food safety and public health issue due to its high morbidity and mortality in some parts of the world. Identifying mushroom toxins at an early stage of suspected intoxication is crucial for therapeutic decision making. Ibotenic acid, muscimol, 2-amino-4,5-hexadienoic acid and 2-amino-4-pentynoic acid are a group of amino group-containing mushroom toxins that can lead to hallucination and neurotoxicity on humans. However, there is no method established for simultaneous detection of the four toxins. In this present study, a new derivatization method was developed for the determination of these toxins in mushroom and urine samples by ultra-performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS). After sample extraction the extract was directly derivatized by using 9-fluorenylmethyloxycarbonyl chloride and multiple factors affecting derivatization reaction were systematically optimized to enhance method sensitivity. Furthermore, liquid-liquid extraction with dichloromethane was employed for purification of the derivatized products. The method was fully validated for linearity, sensitivity, recovery and precision. Re-coveries of four mushroom toxins were in the range of 85%-101% for urine and 82%-108% for mushroom. The limits of quantification were from 0.05 to 1 mu g/L in urine and 1-20 mu g/kg in mushroom. In addition, the developed method was successfully applied on mushroom samples treated by cooking and digesting with arti-ficial gastric juice, demonstrating that vomitus as well as cooked mushroom and its soup can be used as the valuable materials for identifying mushroom poisoning caused by these four toxins.