scholarly journals Improving the resolving power of Isochronous Mass Spectrometry by employing an in-ring mechanical slit

Author(s):  
J.H. Liu ◽  
X. Xu ◽  
P. Zhang ◽  
P. Shuai ◽  
X.L. Yan ◽  
...  
2020 ◽  
Author(s):  
Elizabeth Neumann ◽  
Lukasz Migas ◽  
Jamie L. Allen ◽  
Richard Caprioli ◽  
Raf Van de Plas ◽  
...  

<div> <div> <p>Small metabolites are essential for normal and diseased biological function but are difficult to study because of their inherent structural complexity. MALDI imaging mass spectrometry (IMS) of small metabolites is particularly challenging as MALDI matrix clusters are often isobaric with metabolite ions, requiring high resolving power instrumentation or derivatization to circumvent this issue. An alternative to this is to perform ion mobility separation before ion detection, enabling the visualization of metabolites without the interference of matrix ions. Here, we use MALDI timsTOF IMS to image small metabolites at high spatial resolution within the human kidney. Through this, we have found metabolites, such as arginic acid, acetylcarnitine, and choline that localize to the cortex, medulla, and renal pelvis, respectively. We have also demonstrated that trapped ion mobility spectrometry (TIMS) can resolve matrix peaks from metabolite signal and separate both isobaric and isomeric metabolites with different localizations within the kidney. The added ion mobility data dimension dramatically increased the peak capacity for molecular imaging experiments. Future work will involve further exploring the small metabolite profiles of human kidneys as a function of age, gender, and ethnicity.</p></div></div>


2015 ◽  
Vol 21 (2) ◽  
pp. 187-193 ◽  
Author(s):  
Richard J. A. Goodwin ◽  
Anna Nilsson ◽  
C. Logan Mackay ◽  
John G. Swales ◽  
Maria K. Johansson ◽  
...  

Mass spectrometry imaging (MSI) provides pharmaceutical researchers with a suite of technologies to screen and assess compound distributions and relative abundances directly from tissue sections and offer insight into drug discovery–applicable queries such as blood-brain barrier access, tumor penetration/retention, and compound toxicity related to drug retention in specific organs/cell types. Label-free MSI offers advantages over label-based assays, such as quantitative whole-body autoradiography (QWBA), in the ability to simultaneously differentiate and monitor both drug and drug metabolites. Such discrimination is not possible by label-based assays if a drug metabolite still contains the radiolabel. Here, we present data exemplifying the advantages of MSI analysis. Data of the distribution of AZD2820, a therapeutic cyclic peptide, are related to corresponding QWBA data. Distribution of AZD2820 and two metabolites is achieved by MSI, which [14C]AZD2820 QWBA fails to differentiate. Furthermore, the high mass-resolving power of Fourier transform ion cyclotron resonance MS is used to separate closely associated ions.


2015 ◽  
Vol T166 ◽  
pp. 014009 ◽  
Author(s):  
X L Tu ◽  
B Mei ◽  
Y H Zhang ◽  
H S Xu ◽  
Yu A Litvinov ◽  
...  

2016 ◽  
Vol 9 (1) ◽  
pp. 179-194 ◽  
Author(s):  
F. Obersteiner ◽  
H. Bönisch ◽  
A. Engel

Abstract. We present the characterization and application of a new gas chromatography time-of-flight mass spectrometry instrument (GC-TOFMS) for the quantitative analysis of halocarbons in air samples. The setup comprises three fundamental enhancements compared to our earlier work (Hoker et al., 2015): (1) full automation, (2) a mass resolving power R = m/Δm of the TOFMS (Tofwerk AG, Switzerland) increased up to 4000 and (3) a fully accessible data format of the mass spectrometric data. Automation in combination with the accessible data allowed an in-depth characterization of the instrument. Mass accuracy was found to be approximately 5 ppm in mean after automatic recalibration of the mass axis in each measurement. A TOFMS configuration giving R = 3500 was chosen to provide an R-to-sensitivity ratio suitable for our purpose. Calculated detection limits are as low as a few femtograms by means of the accurate mass information. The precision for substance quantification was 0.15 % at the best for an individual measurement and in general mainly determined by the signal-to-noise ratio of the chromatographic peak. Detector non-linearity was found to be insignificant up to a mixing ratio of roughly 150 ppt at 0.5 L sampled volume. At higher concentrations, non-linearities of a few percent were observed (precision level: 0.2 %) but could be attributed to a potential source within the detection system. A straightforward correction for those non-linearities was applied in data processing, again by exploiting the accurate mass information. Based on the overall characterization results, the GC-TOFMS instrument was found to be very well suited for the task of quantitative halocarbon trace gas observation and a big step forward compared to scanning, quadrupole MS with low mass resolving power and a TOFMS technique reported to be non-linear and restricted by a small dynamical range.


2020 ◽  
Author(s):  
Mathieu Tiquet ◽  
Raphaël La Rocca ◽  
Daan van Kruining ◽  
Pilar Martinez-Martinez ◽  
Gauthier Eppe ◽  
...  

<p><i>MALDI mass spectrometry imaging (MSI) is a powerful analytical method giving access to the 2D localizations of compounds in a thin section of a sample. To properly discern isobaric compounds in complex biological samples, dynamically harmonized ICR cell (ParaCell©) has been introduce to achieve extreme spectral resolution. However, high resolution MS images realized on a 9.4T FTICR High resolution instrument with recommended parameters suffered from an abnormal shifting of m/z ratios pixel to pixel. Resulting datasets show poor mass accuracy measurements and resolutions under estimations. By following the behavior of the Total Ion Current in function of the number of laser shots, the abnormal mass shifting phenomenon has been linked to the stability of the Total Ion Current (TIC) during images acquisitions. An optimization of laser parameters is proposed in order to limit the observed mass shift to retain machine specifications during MSI analyses. It is also shown that the method has been successfully employed to realize quality MS images with resolution above 1,000,000 in the lipid mass range across the whole image.</i></p>


2021 ◽  
Vol 12 ◽  
Author(s):  
Kai P. Law ◽  
Wei He ◽  
Jianchang Tao ◽  
Chuanlun Zhang

Archaea are differentiated from the other two domains of life by their biomolecular characteristics. One such characteristic is the unique structure and composition of their lipids. Characterization of the whole set of lipids in a biological system (the lipidome) remains technologically challenging. This is because the lipidome is innately complex, and not all lipid species are extractable, separable, or ionizable by a single analytical method. Furthermore, lipids are structurally and chemically diverse. Many lipids are isobaric or isomeric and often indistinguishable by the measurement of mass or even their fragmentation spectra. Here we developed a novel analytical protocol based on liquid chromatography ion mobility mass spectrometry to enhance the coverage of the lipidome and characterize the conformations of archaeal lipids by their collision cross-sections (CCSs). The measurements of ion mobility revealed the gas-phase ion chemistry of representative archaeal lipids and provided further insights into their attributions to the adaptability of archaea to environmental stresses. A comprehensive characterization of the lipidome of mesophilic marine thaumarchaeon, Nitrosopumilus maritimus (strain SCM1) revealed potentially an unreported phosphate- and sulfate-containing lipid candidate by negative ionization analysis. It was the first time that experimentally derived CCS values of archaeal lipids were reported. Discrimination of crenarchaeol and its proposed stereoisomer was, however, not achieved with the resolving power of the SYNAPT G2 ion mobility system, and a high-resolution ion mobility system may be required for future work. Structural and spectral libraries of archaeal lipids were constructed in non-vendor-specific formats and are being made available to the community to promote research of Archaea by lipidomics.


2019 ◽  
Vol 34 (6) ◽  
pp. 1098-1108 ◽  
Author(s):  
Pietro Benettoni ◽  
Hryhoriy Stryhanyuk ◽  
Stephan Wagner ◽  
Felix Kollmer ◽  
Jairo H. Moreno Osorio ◽  
...  

ToF-SIMS boundaries were pushed to enhance lateral resolution and mass resolving power for chemical imaging of nanoparticles in biological systems.


RSC Advances ◽  
2018 ◽  
Vol 8 (11) ◽  
pp. 6183-6191 ◽  
Author(s):  
Eduardo M. Schmidt ◽  
Marcos A. Pudenzi ◽  
Jandyson M. Santos ◽  
Celio F. F. Angolini ◽  
Rosana C. L. Pereira ◽  
...  

The performance of the high-field MegaOrbitrap Fourier transform mass spectrometer (FT-MS) with electrospray ionization (ESI) was evaluated to perform petroleum sample characterization via classical petroleomics approaches.


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