Time-of-flight mass spectrometry with a compact two-stage electrostatic mirror: Metastable-ion studies with high mass resolution and ion emission from thick insulators

1991 ◽  
Vol 5 (1) ◽  
pp. 40-43 ◽  
Author(s):  
A. Brunelle ◽  
S. Della-Negra ◽  
J. Depauw ◽  
H. Joret ◽  
Y. Le Beyec
2018 ◽  
Author(s):  
Wenfa Ng

Intact biomolecules carry its identity through its atomic constituents and mass, while fragmented biomolecules require reconstruction for their identity to be retrieved. Hence, for profiling biomolecules in mixtures, the goal would be the gentle ionization of biomolecules by mass spectrometry without inducing fragmentation. Doing so generates an ensemble of ionized intact biomolecules able to be profiled by high sensitivity time-of-flight detector for accurate determination of each biomolecule mass, and thus, identity. Specifically, in time-of-flight detection, high mass resolution determination would require high sensitivity in detecting small differences in time of arrival of biomolecule ions to the detector. While current time-of-flight mass spectrometry provides high mass resolution, greater mass resolution is needed for discriminating different biomolecules in a mixture, where mass differences between biomolecules could be at the sub-Dalton level. With the ability to reliably detect biomolecules with sub-Dalton mass resolution, mass spectrometry with time-of-flight detector such as matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) could find use in identifying the compendium of biomolecules present in a mixture without tedious and time-consuming separation. The larger question would subsequently be coupling sample preparation needs with the conditions conducive for MALDI-TOF MS analysis. Overall, high mass resolution mass spectrometry techniques for profiling biomolecules would find use as an enabling tool in many areas of analytical science and biological sciences such as proteomics and metabolomics.


2018 ◽  
Author(s):  
Wenfa Ng

Intact biomolecules carry its identity through its atomic constituents and mass, while fragmented biomolecules require reconstruction for their identity to be retrieved. Hence, for profiling biomolecules in mixtures, the goal would be the gentle ionization of biomolecules by mass spectrometry without inducing fragmentation. Doing so generates an ensemble of ionized intact biomolecules able to be profiled by high sensitivity time-of-flight detector for accurate determination of each biomolecule mass, and thus, identity. Specifically, in time-of-flight detection, high mass resolution determination would require high sensitivity in detecting small differences in time of arrival of biomolecule ions to the detector. While current time-of-flight mass spectrometry provides high mass resolution, greater mass resolution is needed for discriminating different biomolecules in a mixture, where mass differences between biomolecules could be at the sub-Dalton level. With the ability to reliably detect biomolecules with sub-Dalton mass resolution, mass spectrometry with time-of-flight detector such as matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) could find use in identifying the compendium of biomolecules present in a mixture without tedious and time-consuming separation. The larger question would subsequently be coupling sample preparation needs with the conditions conducive for MALDI-TOF MS analysis. Overall, high mass resolution mass spectrometry techniques for profiling biomolecules would find use as an enabling tool in many areas of analytical science and biological sciences such as proteomics and metabolomics.


2021 ◽  
Vol 928 ◽  
Author(s):  
S.W. Miller ◽  
J.R. Ulibarri-Sanchez ◽  
B.D. Prince ◽  
R.J. Bemish

Orthogonal time-of-flight mass spectrometry has been used to characterize the kinetic energy and charged species distributions from an in vacuo electrospray ion source for four different ionic liquids at volumetric flow rates between 0.3 and 3.3 nanolitres per second. In all cases, the mass spectra revealed charged species consisting of singly charged and multiply charged ions as well as two broad, unresolved droplet distributions occurring in the 104 to 106 atomic mass unit per charge range. The mean jet velocity and mean jet breakup potential were established from analysis of the energy profile of the high mass-to-charge droplets. At the jet breakup point, we find the energy loss and the jet diameter flow rate dependence of the electrospray beam to be similar to that determined by Gamero-Castaño (Phys. Fluids, vol. 20, 2008, 032103; Phys. Rev. Fluids, vol. 8, 2021, 013701) for 1-ethyl-3-methylimidazolium bis(trifluromethylsulfonyl)imide at similar volumetric flow rates. Similar trends are observed for all four liquids over the flow regime. A jet instability analysis revealed that jet electrification and viscous effects drive the jet breakup from the case of an uncharged, inviscid jet; jet breakup occurs at droplet and jet radius ratios that deviate from 1.89. Using the analytically determined ratio and the beam profile, different species are modelled to reconstruct the mass spectra; primary droplets constitute only a fraction of the total species present. The populations of the species are discussed.


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