ABSTRACT
To study the substances in fudosteine, one synthetic by-product and five forced degradation products were detected by hydrophilic interaction chromatography (HILIC). Quadrupole-time-of-flight mass spectrometry (Q-TOF MS) was used for accurate mass determination and product ion scanning. Five related substances were identified in the products of mass spectra fragmentations elucidation, and verified further according to synthetic process and stress testing results. The results obtained are valuable for fudosteine manufacturing process control and quality assurance.
ABSTRACT
The present study was designed to systematically investigate the ESI-MS(n) behavior of a complex 3, 7-O-glycosyl flavonol, kaempferol 3-O-α-L-[2,3-di-O-β-D-(6-E-p-coumaroyl)glucopyranosyl]-rhamnopyranosyl-7-O-α-L-rhamnopyranoside (KO) isolated from Epimedium wushanense, and to address the elimination priority among different glycosylation sites and different sugars/substituents. The direct-infusion ESI-MS(n) experiment of KO was performed on a hybrid LTQ-Orbitrap Velos Pro mass spectrometer in both negative and positive ion modes by three different fragmentation mechanisms (CID, HCD, and PQD). The CID, HCD, and PQD analyses of KO exhibited remarkable discrimination in respect of the scan range, richness, and distribution of product ions through the entire spectra. KO experienced different fragmentation pathways between two ionization modes: the negative mode CID of KO eliminated the glycosyl portions (priority: 7-sugar > 3-substituent and terminal substituents > inner sugar) and produced aglycone product ions at m/z 284.03/285.04; however, abundant sodium-adduct B(3)2 together with subsequent (i,j)X(3)0 cleavages were found characteristic for the positive mode CID-MS(n). The fragmentation pathways by CID for KO were proposed by analyzing the high accuracy ESI-MS(n) data. Complementary structural information of KO regarding the aglycone and glycosyl portions was obtained by analyzing the ESI-MS(n) data in both ionization modes. In conclusion, the LTQ-Orbitrap method facilitates highly reliable qualitative analysis of bioactive flavonoids with three alternative fragmentation modes.
Subject(s)
Epimedium , Chemistry , Flavonols , Glycosides , Glycosylation , Herbal Medicine , Plant Extracts , Chemistry , Spectrometry, Mass, Electrospray Ionization , Methods , Tandem Mass Spectrometry , MethodsABSTRACT
Since alkaloids are the major active constituents of Rhizoma corydalis (RC), a convenient and accurate analytical method is needed for their identification and characterization. Here we report a method to profile the alkaloids in RC based on liquid chromatography-tandem quadrupole time-of-flight mass spectrometry (LC-Q-TOF-MS/MS). A total of 16 alkaloids belonging to four different classes were identified by comparison with authentic standards. The fragmentation pathway of each class of alkaloid was clarified and their differences were elucidated. Furthermore, based on an analysis of fragmentation pathways and alkaloid profiling, a rapid and accurate method for the identification of unknown alkaloids in RC is proposed. The method could also be useful for the quality control of RC.
ABSTRACT
Objective To analyze the fragments of 3 isoflavones and their isoflavone aglycones of Semen Sojae Praeparatum by electron spray ion trap mass spectrometry (ESI-MS), and to study the fragmentation pathway by major fragment ions. Methods Samples were fed into the instrument in the positive andnegative modes, and the fragments of the samples were yielded by multi-stage ion trap mass spectrometry (ESI-MS). The fragment ions of isoflavones and their isoflavone aglyconeswere analyzed. Results In the positive mode, ion peaks m/z 417, 255, 227, 199, 137, and 119 were detected for daidzin and daidzein; m/z 447, 285, 270, and 229 for glycitin and glycitein; and m/z 433, 271, 253, 243, 215, and 153 for genistin and genistein. In negative mode, ion peaksm/z 461, 415, 253, 225, 209, and 197 were detected for daidzin and daidzein; m/z 491, 445, 283, and 268 for glycitin and glycitein; and m/z 477, 269, 268, and 225 for genistin and genistein. Conclusion In the positive mode, daidzin and daidzein are fragmented by losing -Glu and -CO and Retro Diels-Alder (RDA) reaction; glycitin and glycitein are fragmented by losing -Glu, -CO, and -CH3; genistin and genistein are fragmented by losing -Glu, -CO, -H2O and RDA reaction. In negative mode, ions fragment [M+HCOO]- is produced by isoflavone glucosides, and daidzin and daidzein are fragmented by losing -Glu, -CO, -2CO and -CO2; glycitin and glycitein are fragmented by losing -Glu, -H, and -CH3; and genistin and genistein are fragmented by losing -Glu, -H, and-CO2.; glycitin amd glycitein are fragmented by losing -Glu-H, and -CH3; and genistin and genistein are fragmented by losing -Gli, -H, and -CO2.
ABSTRACT
OBJECTIVE: To investigate fragmentation pathways of amoxicillin using electrospray ionization multi-stage tandem mass spectrometry,and to provide reference for quality and quantity analysis of amoxicillin.METHODS: Amoxicillin was further purified by high performance liquid chromatography,and the fragmentation mechanisms were investigated by electrospray ionization multi-stage tandem mass spectrometer.RESULTS: The ?-lactam ring of amoxicillin has three different opening modes;2 kinds of different m/z:114 ion fragments are obtained by two different fragmentation pathways;m/z:349 ion fragments can be a characteristic fragment of amoxicillin for quality and quantity analysis of amoxicillin.CONCLUSION: The method is sensitive and accurate for further study of transformation and metabolism of amoxicillin and its quality and quantity analysis.