scholarly journals Mass Spectrometry Imaging Using Dynamically Harmonized FT-ICR at Million Resolving Power: Rationalizing and Optimizing Sample Preparation and Instrumental Parameters

2020 ◽  
Author(s):  
Mathieu Tiquet ◽  
Raphaël La Rocca ◽  
Daan van Kruining ◽  
Pilar Martinez-Martinez ◽  
Gauthier Eppe ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
High Resolution ◽  
Mass Spectrometry Imaging ◽  
Mass Range ◽  
Maldi Mass Spectrometry ◽  
Mass Accuracy ◽  
Ion Current ◽  
Resolving Power ◽  
Lipid Mass ◽  
The Stability

<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>

scholarly journals Mass Spectrometry Imaging Using Dynamically Harmonized FT-ICR at Million Resolving Power: Rationalizing and Optimizing Sample Preparation and Instrumental Parameters

2020 ◽  
Author(s):  
Mathieu Tiquet ◽  
Raphaël La Rocca ◽  
Daan van Kruining ◽  
Pilar Martinez-Martinez ◽  
Gauthier Eppe ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
High Resolution ◽  
Mass Spectrometry Imaging ◽  
Mass Range ◽  
Maldi Mass Spectrometry ◽  
Mass Accuracy ◽  
Ion Current ◽  
Resolving Power ◽  
Lipid Mass ◽  
The Stability

<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>

scholarly journals Ultra-High Mass Resolving Power, Mass Accuracy, and Dynamic Range MALDI Mass Spectrometry Imaging by 21-T FT-ICR MS

2020 ◽  
Vol 92 (4) ◽  
pp. 3133-3142 ◽  
Author(s):  
Andrew P. Bowman ◽  
Greg T. Blakney ◽  
Christopher L. Hendrickson ◽  
Shane R. Ellis ◽  
Ron M. A. Heeren ◽  
...  
Keyword(s):  
Mass Spectrometry Imaging ◽  
Dynamic Range ◽  
Maldi Mass Spectrometry ◽  
Mass Accuracy ◽  
Resolving Power ◽  
High Mass ◽  
Mass Resolving Power ◽  
Ft Icr Ms ◽  
Maldi Mass Spectrometry Imaging ◽  
Ft Icr

An Analysis of Dissociation of Molecules in a High Resolution Electron Microscope

1973 ◽  
Vol 31 ◽  
pp. 486-487
Author(s):  
Mihir Parikh
Keyword(s):  
Electron Microscope ◽  
High Resolution ◽  
Cross Sections ◽  
Resolving Power ◽  
Peak Intensity ◽  
Molecular Film ◽  
Resolution Electron ◽  
Dissociation Cross Section ◽  
High Resolution Electron Microscope ◽  
The Stability

It is well known that the resolution of bio-molecules in a high resolution electron microscope depends not just on the physical resolving power of the instrument, but also on the stability of these molecules under the electron beam. Experimentally, the damage to the bio-molecules is commo ly monitored by the decrease in the intensity of the diffraction pattern, or more quantitatively by the decrease in the peaks of an energy loss spectrum. In the latter case the exposure, EC, to decrease the peak intensity from IO to I’O can be related to the molecular dissociation cross-section, σD, by EC = ℓn(IO /I’O) /ℓD. Qu ntitative data on damage cross-sections are just being reported, However, the microscopist needs to know the explicit dependence of damage on: (1) the molecular properties, (2) the density and characteristics of the molecular film and that of the support film, if any, (3) the temperature of the molecular film and (4) certain characteristics of the electron microscope used

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