Detection of gyromitrin-induced mushroom poisoning by an isotope-coded derivatization strategy combined with UPLC-MS/MS and its application

Gyromitrin is the main toxic metabolite produced from the false morel such as Gyromitra esculenta , which has a long history of causing food poisoning. However, how to identify the gyromitrin-induced poisoning is difficult because the biomarker of gyromitrin in vivo is still unclear. In this study, a novel isotope-coded method combined with the derivatization strategy was first developed for the accurate quantification of gyromitrin in urine and plasma by ultra-performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS). The major parameters affecting the derivatization efficiency were systematically investigated, and the p-tolualdehyde-d 4 was employed to form the isotope internal standard. The developed method was fully validated with the limit of detection (LOD) of 1 µg/L in urine and plasma. The recoveries were between 88 % and 111 % with the inter-day precision less than 13 %. An exposure study in 12 rats was conducted to determine urinary excretion of gyromitrin and its metabolite monomethylhydrazine (MMH). The mean urinary excretion rates of gyromitrin were 3.45 % (low dose) and 4.93 % (high dose), while the excretion rate of MMH were 0.20 % and 0.36 %. After exposure for 48 h, no gyromitrin and MMH was detected in rat urine. The results suggested that gyromitrin is a valuable biomarker for identification of gyromitrin-induced mushroom poisoning.