Jian Long-Hai, Hu Chun, Yu Hong, Wang Ke, Ji Shen
Shanghai Institute for Food and Drug Control, Shanghai 201203, China.
Zhongguo Zhong Yao Za Zhi. 2013 Jul;38(14):2338-42.
A rapid method of Liquid chromatography-quadrupole time-of-flight mass spectrometry (LC-Q-TOF-MS) combined with pyridinium chlorochromate (PCC) oxidation has been developed to determine chemical structures of two novel isomers in bear bile powder. Derivatives of ursodeoxycholic acid (UDCA) and chenodeoxycholic acid (CDCA) were semi-synthesized by PCC oxidation, then were analyzed by LC-Q-TOF-MS. Separation was carried out on a reverse column with the mobile phase of acetonitrile-0.1% formic acid (45:55). The data of Q-TOF-MS was acquired by MS, MS/MS, positive and negative modes. Since UDCA and CDCA were stereochemical isomeric at an alcohol position, two oxidation products were same and have been confirmed by LC-Q-TOF-MS. Other two products were also determined based on the PCC oxidation theory. Samples of bear bile powder were dissolved by methanol and measured by LC-Q-TOF-MS. Two unknown peaks were found and identified by matching their retention times and accurate mass spectra ions with PCC oxidation productS. Finally, the structures of two new bile acids in bear bile powder were confirmed as 3alpha-hydroxy-7-oxo-5beta-cholanic acid, 7alpha-hydroxy-3-oxo-5beta-cholanic acid, respectively.
已开发出一种快速的液相色谱-四极杆飞行时间质谱法（LC-Q-TOF-MS）与氯铬酸吡啶鎓（PCC）氧化相结合的方法，用于确定熊胆粉中两种新型异构体的化学结构。通过PCC氧化半合成熊去氧胆酸（UDCA）和鹅去氧胆酸（CDCA）的衍生物，然后用LC-Q-TOF-MS进行分析。在反相柱上进行分离，流动相为乙腈-0.1%甲酸（45:55）。通过MS、MS/MS、正模式和负模式获取Q-TOF-MS数据。由于UDCA和CDCA在醇位置上是立体化学异构体，两种氧化产物相同，并已通过LC-Q-TOF-MS得到证实。还基于PCC氧化理论确定了其他两种产物。熊胆粉样品用甲醇溶解，并用LC-Q-TOF-MS进行测定。发现了两个未知峰，并通过将它们的保留时间和精确质谱离子与PCC氧化产物进行匹配来鉴定。最后，熊胆粉中两种新胆汁酸的结构分别确认为3α-羟基-7-氧代-5β-胆烷酸、7α-羟基-3-氧代-5β-胆烷酸。
