Standardized Identification of Compound Structure in Tibetan Medicine Using Ion Trap Mass Spectrometry and Multiple-Stage Fragmentation Analysis

Tibetan medicines are complex and contain numerous unknown compounds, making in-depth research on their molecular structures crucial. Liquid chromatography-electrospray ionization time-of-flight mass spectrometry (LC-ESI-TOF-MS) is commonly used to extract Tibetan medicine; however, many unpredictable unknown compounds remain after using the spectrum database. The present article developed a universal method for identifying components in Tibetan medicine using ion trap mass spectrometry (IT-MS). The method includes standardized and programmed protocols for sample preparation, MS setting, LC prerun, method establishment, MS acquisition, multiple-stage MS operation, and manual data analysis. Two representative compounds in the Tibetan medicine Abelmoschus manihot seeds were identified using multiple-stage fragmentation, with a detailed analysis of typical compound structures. In addition, the article discusses aspects such as ion mode selection, mobile phase adjustment, scanning range optimization, collision energy control, collision mode switchover, fragmentation factors, and limitations of the method. The developed standardized analysis method is universal and can be applied to unknown compounds in Tibetan medicine.