Publications

Showing 33 results for Author: John F. Cahill

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Nov, 2023

Journal

Probing ligand removal and ordering at quantum dot surfaces using vibrational sum frequency generation spectroscopy

Hypothesis: Controlling nanomaterial interfaces for emerging technologies has driven the need to understand the molecular species located there; however, challenges arise using traditional analytical techniques to directly characterize the molecular structure and local environments of these interfacial species due to their low relative populations. We hypothesized that vib…
Nov, 2023

Journal

Solvent effects on differentiation of mouse brain tissue using laser microdissection ‘cut and drop’ sampling with direct mass spectral analysis

Rationale: Laser microdissection‐liquid vortex capture/electrospray ionization mass spectrometry (LMD‐LVC/ESI‐MS) has potential for on‐line classification of tissue but an investigation into what analytical conditions provide best spectral differentiation has not been conducted. The effects of solvent, ionization polarity, and spectral acquisition parameters on differentia…
Nov, 2023

Journal

Geochemical Evidence for Rare-Earth Element Mobilization during Kaolin Diagenesis

This study investigates how saprolization influences inherent rare-earth element (REE) source rock signatures and how depositional environment(s) and diagenetic reactions ultimately impact the REE signature within sedimentary kaolin bodies. Rare-earth element geochemistry signatures are particularly useful for tracking element sources and mobility and are, therefore, power…
May, 2023

Journal

Characterization and Application of a Hybrid Optical Microscopy/Laser Ablation Liquid Vortex Capture/Electrospray Ionization System for Mass Spectrometry Imaging with Sub-micrometer Spatial Resolution

A commercial optical microscope, laser microdissection instrument was coupled with an electrospray ionization mass spectrometer via a low profile liquid vortex capture probe to yield a hybrid optical microscopy/mass spectrometry imaging system. The instrument has bright-field and fluorescence microscopy capabilities in addition to a highly focused UV laser beam that is uti…
Mar, 2017

Journal

Characterization of core-shell MOF particles by depth profiling experiments using on-line single particle mass spectrometry

Materials with core-shell structures have distinct properties that lend themselves to a variety of potential applications. Characterization of small particle core-shell materials presents a unique analytical challenge. Herein, single particles of solid-state materials with core-shell structures were measured using on-line aerosol time-of-flight mass spectrometry (ATOFMS).…
Aug, 2016

Journal

Laser dissection sampling modes for direct mass spectral analysis

RationaleLaser microdissection coupled directly with mass spectrometry provides the capability of on-line analysis of substrates with high spatial resolution, high collection efficiency, and freedom on shape and size of the sampling area. Establishing the merits and capabilities of the different sampling modes that the system provides is necessary in order to select the be…
Jul, 2016

Journal

Absolute Quantitation of Propranolol from Spatially Distinct 20- and 40–μm Dissections of Brain, Liver, and Kidney Thin Tissue Sections by Laser Microdissection – Liquid Vortex Capture -Mass Spectrometry

Spatial resolved quantitation of chemical species in thin tissue sections by mass spectrometric methods has been constrained by the need for matrix-matched standards or other arduous calibration protocols and procedures to mitigate matrix effects (e.g., spatially varying ionization suppression). Reported here is the use of laser “cut and drop” sampling with a laser microdi…
Mar, 2016

Journal

Quantitative Metrics for Assessment of Chemical Image Quality and Spatial Resolution

Rationale: Currently objective/quantitative descriptions of the quality and spatial resolution of mass spectrometry derived chemical images are not standardized. Development of these standardized metrics is required to objectively describe chemical imaging capabilities of existing and/or new mass spectrometry imaging technologies. Such metrics would allow unbiased judgment…
Jan, 2016

Journal

Comparison of Internal Energy Distributions of Ions Created by Electrospray Ionization and Laser Ablation-Liquid Vortex Capture-Electrospray Ionization

Recently a number of techniques have combined laser ablation with liquid capture for mass spectrometry spot sampling and imaging applications. The newly developed non-contact liquid-vortex capture probe has been used to efficiently collect 355 nm UV laser ablated material in a continuous flow solvent stream in which the captured material dissolves and then undergoes electr…

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Publications

Probing ligand removal and ordering at quantum dot surfaces using vibrational sum frequency generation spectroscopy

Solvent effects on differentiation of mouse brain tissue using laser microdissection ‘cut and drop’ sampling with direct mass spectral analysis

Geochemical Evidence for Rare-Earth Element Mobilization during Kaolin Diagenesis

Characterization and Application of a Hybrid Optical Microscopy/Laser Ablation Liquid Vortex Capture/Electrospray Ionization System for Mass Spectrometry Imaging with Sub-micrometer Spatial Resolution

Characterization of core-shell MOF particles by depth profiling experiments using on-line single particle mass spectrometry

Laser dissection sampling modes for direct mass spectral analysis

Absolute Quantitation of Propranolol from Spatially Distinct 20- and 40–μm Dissections of Brain, Liver, and Kidney Thin Tissue Sections by Laser Microdissection – Liquid Vortex Capture -Mass Spectrometry

Quantitative Metrics for Assessment of Chemical Image Quality and Spatial Resolution

Comparison of Internal Energy Distributions of Ions Created by Electrospray Ionization and Laser Ablation-Liquid Vortex Capture-Electrospray Ionization