scholarly journals The Q Exactive HF, a Benchtop Mass Spectrometer with a Pre-filter, High-performance Quadrupole and an Ultra-high-field Orbitrap Analyzer

2014 ◽  
Vol 13 (12) ◽  
pp. 3698-3708 ◽  
Author(s):  
Richard Alexander Scheltema ◽  
Jan-Peter Hauschild ◽  
Oliver Lange ◽  
Daniel Hornburg ◽  
Eduard Denisov ◽  
...  
Keyword(s):  
Mass Spectrometer ◽  
High Field ◽  
High Performance ◽  
Ultra High Field ◽  
Q Exactive ◽  
Orbitrap Analyzer

scholarly journals The “Loopole” Antenna: A Hybrid Coil Combining Loop and Electric Dipole Properties for Ultra-High-Field MRI

2020 ◽  
Vol 2020 ◽  
pp. 1-9
Author(s):  
Karthik Lakshmanan ◽  
Martijn Cloos ◽  
Ryan Brown ◽  
Riccardo Lattanzi ◽  
Daniel K. Sodickson ◽  
...  
Keyword(s):  
Current Distribution ◽  
Electric Dipole ◽  
High Field ◽  
High Performance ◽  
Signal To Noise Ratio ◽  
Ultra High Field ◽  
High Field Mri ◽  
Electric Dipoles ◽  
Ultra High Field Mri ◽  
Free Current

Purpose. To revisit the “loopole,” an unusual coil topology whose unbalanced current distribution captures both loop and electric dipole properties, which can be advantageous in ultra-high-field MRI. Methods. Loopole coils were built by deliberately breaking the capacitor symmetry of traditional loop coils. The corresponding current distribution, transmit efficiency, and signal-to-noise ratio (SNR) were evaluated in simulation and experiments in comparison to those of loops and electric dipoles at 7 T (297 MHz). Results. The loopole coil exhibited a hybrid current pattern, comprising features of both loops and electric dipole current patterns. Depending on the orientation relative to B0, the loopole demonstrated significant performance boost in either the transmit efficiency or SNR at the center of a dielectric sample when compared to a traditional loop. Modest improvements were observed when compared to an electric dipole. Conclusion. The loopole can achieve high performance by supporting both divergence-free and curl-free current patterns, which are both significant contributors to the ultimate intrinsic performance at ultra-high field. While electric dipoles exhibit similar hybrid properties, loopoles maintain the engineering advantages of loops, such as geometric decoupling and reduced resonance frequency dependence on sample loading.

scholarly journals Mass Spectrometry-based Proteomics Using Q Exactive, a High-performance Benchtop Quadrupole Orbitrap Mass Spectrometer

2011 ◽  
Vol 10 (9) ◽  
pp. M111.011015 ◽  
Author(s):  
Annette Michalski ◽  
Eugen Damoc ◽  
Jan-Peter Hauschild ◽  
Oliver Lange ◽  
Andreas Wieghaus ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Mass Spectrometer ◽  
High Performance ◽  
Orbitrap Mass Spectrometer ◽  
Q Exactive

scholarly journals Rapid and Deep Proteomes by Faster Sequencing on a Benchtop Quadrupole Ultra-High-Field Orbitrap Mass Spectrometer

2014 ◽  
Vol 13 (12) ◽  
pp. 6187-6195 ◽  
Author(s):  
Christian D. Kelstrup ◽  
Rosa R. Jersie-Christensen ◽  
Tanveer S. Batth ◽  
Tabiwang N. Arrey ◽  
Andreas Kuehn ◽  
...  
Keyword(s):  
Mass Spectrometer ◽  
High Field ◽  
Ultra High Field ◽  
Orbitrap Mass Spectrometer

Detection and identification of Catalpol metabolites in the rat plasma, urine and faeces using ultra-high performance liquid chromatography-Q Exactive hybrid quadrupole-orbitrap high-resolution accurate mass spectrometry

2020 ◽  
Vol 21 ◽  
Author(s):  
Zedong Xiang ◽  
Shaoping Wang ◽  
Haoran Li ◽  
Pingping Dong ◽  
Fan Dong ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
High Resolution ◽  
High Performance ◽  
Mass Measurement ◽  
Neutral Loss ◽  
Rat Plasma ◽  
Accurate Mass ◽  
Chromatographic Retention ◽  
Rat Urine ◽  
Q Exactive

Background:: Catalpol, an iridoid glycoside, is one of the richest bioactive components present in Rehmannia glutinosa. More and more metabolites of drugs have exhibit various pharmacological effects, thus providing guidance for clinical application. However, few researches have paid attention on the metabolism of catalpol. Objective:: This study aimed to establish a rapid and effective method to identify catalpol metabolites and evaluate the biotransformation pathways of catalpol in rats. Methods:: In this study, catalpol metabolites in rat urine, plasma and faeces were analyzed by UHPLC-Q-Exactive MS for the characterization of metabolism of catalpol. Based on high-resolution extracted ion chromatograms (HREICs) and parallel reaction monitoring mode (PRM), metabolites of catalpol were identified by comparing the diagnostic product ions (DPIs), chromatographic retention times, neutral loss fragments (NLFs) and accurate mass measurement with those of catalpol reference standard. Results: A total of 29 catalpol metabolites were detected and identified in both negative and positive ion modes. Nine metabolic reactions including deglycosylation, hydroxylation, dihydroxylation, hydrogenation, dehydrogenation, oxidation of methylene to ketone, glucuronidation, glycine conjugation and cysteine conjugation were proposed. Conclusion:: A rapid and effective method based on UHPLC-Q-Exactive MS was developed to mine the metabolism information of catalpol. Results of metabolites and biotransformation pathways of catalpol suggested that when orally administrated, catalpol was firstly metabolized into catalpol aglycone, after which phase Ⅰ and phase Ⅱ reactions occurred. However, hydrophilic chromatography-mass spectrometry still needed to further find the polar metabolites of catalpol.

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