基质辅助激光解吸电离飞行时间质谱法对中药材霉菌污染的快速鉴定

Rapid Identification of Microbial Contamination in Herbs by Matrix-assisted Laser Desorption/Ionization Time of Flight Mass Spectrometry

通过N-烷基吡啶同位素季铵化反应(NAPIQ)结合基质辅助激光解吸电离飞行时间质谱(MALDI-TOF MS)对中药材的霉变情况进行了快速鉴定。运用氯仿对中药材中的甾醇进行提取后,以吡啶、氘代吡啶以及三氟甲磺酸酐作为衍生化试剂对提取出的甾醇进行衍生化反应以提高其质谱响应,并利用MALDI-TOF MS进行检测。利用该方法在新鲜的药材中仅检测到谷甾醇、豆甾醇等植物甾醇,而在霉变的药材中,除了植物甾醇外,还检测到羊毛甾醇等动物甾醇以及麦角甾醇等菌类甾醇。将该方法与药典中的微生物计数法进行了对照,在只检测到植物甾醇的新鲜药材中未发现霉菌,而在产生了动物甾醇和菌类甾醇的霉变药材中检测到的微生物数均大于药典规定的10~2 cfu/g,证明了该方法符合药典标准,可以对中药材受霉菌污染的状况进行快速评价。

A matrix-assisted laser desorption/ionization time of flight mass spectrometric (MALDI-TOF MS ) method with N-alkylpyridinium isotope quaternization (NAPIQ ) was developed for the rapid identification of microbial contamination in herbs in this paper.The sterols in herbs were extracted with chloroform,and then derivatized with three reagents, i.e.pyridine,D 5-pyridine and trifluoromethanesulfonic anhydride.The derivatization could significantly enhance the ionization of sterols in the analysis by MALDI-TOF MS.Only phytosterols such as sitosterols and stigmasterols in the fresh traditional Chinese medicine were detected by this method,while the zoosterols and the mycosterol such as lanosterol and ergosterol were observed in the mass spectra of moldy herbs. Furthermore,the method was compared with the microbial enumeration method in Chinese Pharmacopoeia (2015 edition ).No molds in the fresh herbs were detected by the microbial enumeration method,while the microbial counts in the moldy herbs significantly exceeded the threshold of 10 2 cfu/g.Results showed that the MALDI-TOF MS combined with NAPIQ provided an alternative method for the identification of potential moldy herbs.