J Am Soc Mass Spectrom
December 2024
Mass spectrometry imaging (MSI) is constantly improving in spatial resolving power, throughput and mass resolution. Although beneficial, these improvements increase data set size and content. The larger data requires correspondingly fast computer-based analyses.
View Article and Find Full Text PDFThis paper describes the development and initial results from a secondary ion mass spectrometer coupled with microscope mode detection. Stigmatic ion microscope imaging enables us to decouple the primary ion (PI) beam focus from spatial resolution and is a promising route to attaining higher throughput for mass spectrometry imaging (MSI). Using a commercial C PI beam source, we can defocus the PI beam to give uniform intensity across a 2.
View Article and Find Full Text PDFPrevious studies have shown that the use of a 20 keV water cluster beam as a primary beam for the analysis of organic and bio-organic systems resulted in a 10-100 times increase in positive molecular ion yield for a range of typical analytes compared to C and argon cluster beams. This resulted in increased sensitivity to important lipid molecules in the bioimaging of rat brain. Building on these studies, the present work compares 40 and 70 keV water cluster beams with cluster beams composed of pure argon, argon and 10%CO, and pure CO.
View Article and Find Full Text PDFMillions of diverse molecules constituting the lipidome act as important signals within cells. Of these, cardiolipin (CL) and phosphatidylethanolamine (PE) participate in apoptosis and ferroptosis, respectively. Their subcellular distribution is largely unknown.
View Article and Find Full Text PDFIn secondary ion mass spectrometry (SIMS), the beneficial effect of cesium implantation or flooding on the enhancement of negative secondary ion yields has been investigated in detail for various semiconductor and metal samples. All results have been obtained for monatomic ion bombardment. Recent progress in SIMS is based to a large extent on the development and use of cluster primary ions.
View Article and Find Full Text PDFRecent experimental measurements and calculations performed by molecular dynamics computer simulations indicate, for highly energetic C primary ions bombarding molecular solids, the emission of intact molecules is unique. An energy- and angle-resolved neutral mass spectrometer coupled with laser photoionization techniques was used to measure the polar angle distribution of neutral benzo[a]pyrene molecules desorbed by 20-keV [Formula: see text] primary ions and observed to peak at off-normal angles integrated over all possible emission energies. Similarly, computer simulations of 20-keV C projectiles bombarding a coarse-grained benzene system resulted in calculations of nearly identical polar angle distributions.
View Article and Find Full Text PDFThe angular distribution of intact organic molecules desorbed by energetic C(60) primary ions was probed both experimentally and with molecular dynamics computer simulations. For benzo[a]pyrene, the angular distribution of intact molecules is observed to peak at off-normal angles. Molecular dynamics computer simulations on a similar system show the mechanism of desorption involves fast deposition of energy followed by fluid-flow and effusive-type emission of intact molecules.
View Article and Find Full Text PDFTime-of-flight secondary ion mass spectrometry (TOF-SIMS) has unique capabilities in the area of high-resolution mass spectrometric imaging of biological samples. The technique offers parallel detection of native and non-native molecules at physiological concentrations with potentially submicrometer spatial resolution. Recent advances in SIMS technology have been focused on generating new ion sources that can in turn be used to eject more intact molecular and biological characteristic species from a sample.
View Article and Find Full Text PDFA buckminsterfullerene (C60)-based primary ion beam system has been developed for routine application in TOF-SIMS analysis of organic materials. The ion beam system is described, and its performance is characterized. Nanoamp beam currents of C60+ are obtainable in continuous current mode.
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