scholarly journals Fragmentation Pathways of Sweet Dipeptides by High Resolution (+) ESI Mass Spectrometry

2013 ◽  
Author(s):  
Maroula G. Kokotou ◽  
Eleni Siapi ◽  
Nikolaos S. Thomaidis ◽  
George Kokotos
Keyword(s):  
Mass Spectrometry ◽  
High Resolution ◽  
Fragmentation Pathways ◽  
Esi Mass Spectrometry

Study of the Fragmentation Pathways of Sulfonamides by High-resolution Mass Spectrometry: Application to their Detection in Plasma by Direct Infusion

2020 ◽  
Vol 16 (5) ◽  
pp. 513-519
Author(s):  
Maroula G. Kokotou
Keyword(s):  
Mass Spectrometry ◽  
High Resolution ◽  
High Resolution Mass Spectrometry ◽  
Structural Features ◽  
Direct Infusion ◽  
Sulfonamide Antibiotics ◽  
Fragmentation Pathways ◽  
Fragment Ions ◽  
High Resolution Mass ◽  
Resolution Mass

Background: The high resolving and accuracy power of the HRMS instrument enabled us to identify the product ions and to propose detailed fragmentation pathways and diagnostic fragment ions. Methods: In the present work, the fragmentation pathways of five sulfonamides antibiotics, namely sulfamerazine, sulfathiazole, sulfadiazine, sulfadimethoxine and sulfamethoxazole, by High-Resolution Mass Spectrometry (HRMS) are presented. The HRMS spectra were recorded with a Q-TOF (Time of Flight) spectrometer with Electrospray Ionization (ESI) in both negative and positive mode. Results: Specific characteristic ions for each one of the sulfonamide antibiotics under positive ESI mode are proposed for the first time. Fragment ions of this particular class of analytes may be used to rapidly identify compounds with common structural features. Conclusion: The direct infusion of plasma samples, avoiding any prior chromatographic steps, to identify the existence of sulfonamide antibiotics is demonstrated herein.

scholarly journals A Comprehensive LC-MS and Isolation Study of Cicada Slough as a Crude Drug

2017 ◽  
Vol 12 (11) ◽  
pp. 1934578X1701201 ◽  
Author(s):  
Hiroki Matsumoto ◽  
Katsuhiro Konno ◽  
Kohei Kazuma
Keyword(s):  
Mass Spectrometry ◽  
High Resolution ◽  
Tandem Mass Spectrometry ◽  
Detailed Analysis ◽  
Protocatechuic Acid ◽  
Degree Of Polymerization ◽  
Tandem Mass ◽  
Fragmentation Pathways ◽  
Crude Drug ◽  
Crude Drugs

Cicada slough is one of the traditional crude drugs in East Asia. A comprehensive LC-MS analysis was conducted to overview constituents in a commercially purchased cicada slough as a crude drug. It revealed that there were oligomers of N-acetyldopamine with the degree of polymerization of up to 8. High-resolution tandem mass spectrometry could enable a detailed analysis on their structures by uncovering the presumed fragmentation pathways. Additional isolation experiments disclosed the presence of four known compounds: 2,3’,4’-trihydroxyacetophenone, 2-oxo- N-acetyldopamine, protocatechuic acid, and paeonol. The quantified paeonol content for purchased cicada slough ranged from 3 to 290 μg/g dw crude drug, although wild cicada slough did not show the presence of paeonol.

Exploring the Active Compounds of Traditional Mongolian Medicine Agsirga in Intervention of Novel Coronavirus (2019-nCoV) Based on HPLC-Q-Exactive-MS/MS and Molecular Docking Method

2020 ◽  
Author(s):  
Jie Cheng ◽  
Yuchen Tang ◽  
Baoquan Bao ◽  
Ping Zhang
Keyword(s):  
Mass Spectrometry ◽  
Molecular Docking ◽  
High Resolution ◽  
Mass Spectra ◽  
High Resolution Mass Spectrometry ◽  
Structural Formula ◽  
Active Compounds ◽  
High Resolution Mass ◽  
Q Exactive ◽  
Resolution Mass

<p><a></a><a></a><a></a><a><b>Objective</b></a>: To screen all compounds of Agsirga based on the HPLC-Q-Exactive high-resolution mass spectrometry and find potential inhibitors that can respond to 2019-nCoV from active compounds of Agsirga by molecular docking technology.</p> <p><b>Methods</b>: HPLC-Q-Exactive high-resolution mass spectrometry was adopted to identify the complex components of Mongolian medicine Agsirga, and separated by the high-resolution mass spectrometry Q-Exactive detector. Then the Orbitrap detector was used in tandem high-resolution mass spectrometry, and the related molecular and structural formula were found by using the chemsipider database and related literature, combined with precise molecular formulas (errors ≤ 5 × 10<sup>−6</sup>) , retention time, primary mass spectra, and secondary mass spectra information, The fragmentation regularities of mass spectra of these compounds were deduced. Taking ACE2 as the receptor and deduced compounds as the ligand, all of them were pretreated by discover studio, autodock and Chem3D. The molecular docking between the active ingredients and the target protein was studied by using AutoDock molecular docking software. The interaction between ligand and receptor is applied to provide a choice for screening anti-2019-nCoV drugs.</p> <p><b>Result</b>: Based on the fragmentation patterns of the reference compounds and consulting literature, a total of 96 major alkaloids and stilbenes were screened and identified in Agsirga by the HPLC-Q-Exactive-MS/MS method. Combining with molecular docking, a conclusion was got that there are potential active substances in Mongolian medicine Agsirga which can block the binding of ACE2 and 2019-nCoV at the molecular level.</p>

Analysis of Squalene and Its Transformation By-Products in Latent Fingermarks by Ultrahigh-Pressure Liquid Chromatography-High Resolution Accurate Mass Orbitrap™ Mass Spectrometry

2019 ◽  
Author(s):  
Buddhika Dorakumbura ◽  
Francesco Busetti ◽  
Simon Lewis
Keyword(s):  
Mass Spectrometry ◽  
Liquid Chromatography ◽  
High Resolution ◽  
Storage Conditions ◽  
Ultrahigh Pressure ◽  
Accurate Mass ◽  
Rational Approach ◽  
By Products ◽  
Over Time ◽  
High Resolution Accurate Mass

<p>Transformation of squalene and its by-products in fingermarks over time under different storage conditions (light, dark and underwater) was examined through ultrahigh-pressure liquid chromatography high resolution accurate mass Orbitrap™ mass spectrometry. Complications of assessing fingermark compositional variation over time using multiple samples with varying initial compositions were elucidated and a more rational approach was successfully demonstrated. Squalene was detected in all fresh natural fingermarks and the amount ranged between 0.20 to 11.32 μg/5 fingertips. A notable difference in the transformation of squalene was observed with different storage conditions, where a dark aquatic environment accelerated degradation of squalene compared to dark but dry conditions. Squalene monohydroperoxide was extremely short-lived in natural deposits while the amount of squalene epoxide was still increasing relative to the initial amount, after ageing under dark and aquatic conditions for up to 7 days. Some oxidation by-products of cholesterol were also tentatively identified, which exhibited a growth over time against their initial concentration under any of the storage condition tested. These by-products, therefore, show potential as biomarkers for targeted visualisation of aged deposits.</p>

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