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https://www.readbyqxmd.com/read/27848143/direct-analysis-of-triterpenes-from-high-salt-fermented-cucumbers-using-infrared-matrix-assisted-laser-desorption-electrospray-ionization-ir-maldesi
#1
Måns Ekelöf, Erin K McMurtrie, Milad Nazari, Suzanne D Johanningsmeier, David C Muddiman
High-salt samples present a challenge to mass spectrometry (MS) analysis, particularly when electrospray ionization (ESI) is used, requiring extensive sample preparation steps such as desalting, extraction, and purification. In this study, infrared matrix-assisted laser desorption electrospray ionization (IR-MALDESI) coupled to a Q Exactive Plus mass spectrometer was used to directly analyze 50-μm thick slices of cucumber fermented and stored in 1 M sodium chloride brine. From the several hundred unique substances observed, three triterpenoid lipids produced by cucumbers, β-sitosterol, stigmasterol, and lupeol, were putatively identified based on exact mass and selected for structural analysis...
November 15, 2016: Journal of the American Society for Mass Spectrometry
https://www.readbyqxmd.com/read/27484166/infrared-matrix-assisted-laser-desorption-electrospray-ionization-mass-spectrometry-imaging-analysis-of-biospecimens
#2
M T Bokhart, D C Muddiman
Infrared matrix-assisted laser desorption electrospray ionization (IR-MALDESI) mass spectrometry imaging (MSI) is a technique well suited for analysis of biological specimens. This tutorial review focuses on recent advancements and applications of IR-MALDESI MSI to better understand key biological questions. Through optimization of user-defined source parameters, comprehensive and quantitative MSI data can be obtained for a variety of analytes. The effect of an ice matrix layer is well defined in the context of desorption dynamics and resulting ion abundance...
September 21, 2016: Analyst
https://www.readbyqxmd.com/read/27077488/whole-body-mass-spectrometry-imaging-by-infrared-matrix-assisted-laser-desorption-electrospray-ionization-ir-maldesi
#3
Milad Nazari, Mark T Bokhart, David C Muddiman
Ambient ionization sources for mass spectrometry (MS) have been the subject of much interest in the past decade. Matrix-assisted laser desorption electrospray ionization (MALDESI) is an example of such methods, where features of matrix-assisted laser desorption/ionization (MALDI) (e.g., pulsed nature of desorption) and electrospray ionization (ESI) (e.g., soft-ionization) are combined. One of the major advantages of MALDESI is its inherent versatility. In MALDESI experiments, an ultraviolet (UV) or infrared (IR) laser can be used to resonantly excite an endogenous or exogenous matrix...
2016: Journal of Visualized Experiments: JoVE
https://www.readbyqxmd.com/read/26942738/transomic-analysis-of-forebrain-sections-in-sp2-conditional-knockout-embryonic-mice-using-ir-maldesi-imaging-of-lipids-and-lc-ms-ms-label-free-proteomics
#4
Philip Loziuk, Florian Meier, Caroline Johnson, H Troy Ghashghaei, David C Muddiman
Quantitative methods for detection of biological molecules are needed more than ever before in the emerging age of "omics" and "big data." Here, we provide an integrated approach for systematic analysis of the "lipidome" in tissue. To test our approach in a biological context, we utilized brain tissue selectively deficient for the transcription factor Specificity Protein 2 (Sp2). Conditional deletion of Sp2 in the mouse cerebral cortex results in developmental deficiencies including disruption of lipid metabolism...
May 2016: Analytical and Bioanalytical Chemistry
https://www.readbyqxmd.com/read/26688545/analysis-of-antiretrovirals-in-single-hair-strands-for-evaluation-of-drug-adherence-with-infrared-matrix-assisted-laser-desorption-electrospray-ionization-mass-spectrometry-imaging
#5
Elias P Rosen, Corbin G Thompson, Mark T Bokhart, Heather M A Prince, Craig Sykes, David C Muddiman, Angela D M Kashuba
Adherence to a drug regimen can be a strong predictor of health outcomes, and validated measures of adherence are necessary at all stages of therapy from drug development to prescription. Many of the existing metrics of drug adherence (e.g., self-report, pill counts, blood monitoring) have limitations, and analysis of hair strands has recently emerged as an objective alternative. Traditional methods of hair analysis based on LC-MS/MS (segmenting strands at ≥1 cm length) are not capable of preserving a temporal record of drug intake at higher resolution than approximately 1 month...
January 19, 2016: Analytical Chemistry
https://www.readbyqxmd.com/read/26056514/assessing-drug-and-metabolite-detection-in-liver-tissue-by-uv-maldi-and-ir-maldesi-mass-spectrometry-imaging-coupled-to-ft-icr-ms
#6
Jeremy A Barry, M Reid Groseclose, Guillaume Robichaud, Stephen Castellino, David C Muddiman
Determining the distribution of a drug and its metabolites within tissue is a key facet of evaluating drug candidates. Drug distribution can have a significant implication in appraising drug efficacy and potential toxicity. The specificity and sensitivity of mass spectrometry imaging (MSI) make it a perfect complement to the analysis of drug distributions in tissue. The detection of lapatinib as well as several of its metabolites in liver tissue was determined by MSI using infrared matrix-assisted laser desorption electrospray ionization (IR-MALDESI) coupled to high resolving power Fourier transform ion cyclotron resonance (FT-ICR) mass spectrometers...
February 1, 2015: International Journal of Mass Spectrometry
https://www.readbyqxmd.com/read/25840812/influence-of-desorption-conditions-on-analyte-sensitivity-and-internal-energy-in-discrete-tissue-or-whole-body-imaging-by-ir-maldesi
#7
Elias P Rosen, Mark T Bokhart, H Troy Ghashghaei, David C Muddiman
Analyte signal in a laser desorption/postionization scheme such as infrared matrix-assisted laser desorption electrospray ionization (IR-MALDESI) is strongly coupled to the degree of overlap between the desorbed plume of neutral material from a sample and an orthogonal electrospray. In this work, we systematically examine the effect of desorption conditions on IR-MALDESI response to pharmaceutical drugs and endogenous lipids in biological tissue using a design of experiments approach. Optimized desorption conditions have then been used to conduct an untargeted lipidomic analysis of whole body sagittal sections of neonate mouse...
June 2015: Journal of the American Society for Mass Spectrometry
https://www.readbyqxmd.com/read/25486925/cellular-level-mass-spectrometry-imaging-using-infrared-matrix-assisted-laser-desorption-electrospray-ionization-ir-maldesi-by-oversampling
#8
Milad Nazari, David C Muddiman
Mass spectrometry imaging (MSI) allows for the direct and simultaneous analysis of the spatial distribution of molecular species from sample surfaces such as tissue sections. One of the goals of MSI is monitoring the distribution of compounds at the cellular resolution in order to gain insights about the biology that occurs at this spatial level. Infrared matrix-assisted laser desorption electrospray ionization (IR-MALDESI) imaging of cervical tissue sections was performed using a spot-to-spot distance of 10 μm by utilizing the method of oversampling, where the target plate is moved by a distance that is less than the desorption radius of the laser...
March 2015: Analytical and Bioanalytical Chemistry
https://www.readbyqxmd.com/read/25318460/quantitative-mass-spectrometry-imaging-of-emtricitabine-in-cervical-tissue-model-using-infrared-matrix-assisted-laser-desorption-electrospray-ionization
#9
Mark T Bokhart, Elias Rosen, Corbin Thompson, Craig Sykes, Angela D M Kashuba, David C Muddiman
A quantitative mass spectrometry imaging (QMSI) technique using infrared matrix-assisted laser desorption electrospray ionization (IR-MALDESI) is demonstrated for the antiretroviral (ARV) drug emtricitabine in incubated human cervical tissue. Method development of the QMSI technique leads to a gain in sensitivity and removal of interferences for several ARV drugs. Analyte response was significantly improved by a detailed evaluation of several cationization agents. Increased sensitivity and removal of an isobaric interference was demonstrated with sodium chloride in the electrospray solvent...
March 2015: Analytical and Bioanalytical Chemistry
https://www.readbyqxmd.com/read/25303475/silver-dopants-for-targeted-and-untargeted-direct-analysis-of-unsaturated-lipids-via-infrared-matrix-assisted-laser-desorption-electrospray-ionization-ir-maldesi
#10
Florian Meier, Kenneth P Garrard, David C Muddiman
RATIONALE: Unsaturated lipids play a crucial role in cellular processes as signaling factors, membrane building blocks or energy storage molecules. However, adequate mass spectrometry imaging of this diverse group of molecules remains challenging. In this study we implemented silver cationization for direct analysis by infrared matrix-assisted laser desorption electrospray ionization (IR-MALDESI) to enhance the ion abundances for olefinic lipids and facilitate peak assignment. METHODS: Trace amounts of silver nitrate were doped into the electrospray solvent of an IR-MALDESI imaging source coupled to an Orbitrap mass analyzer...
November 30, 2014: Rapid Communications in Mass Spectrometry: RCM
https://www.readbyqxmd.com/read/25081013/analysis-of-trace-fibers-by-ir-maldesi-imaging-coupled-with-high-resolving-power-ms
#11
Kristin H Cochran, Jeremy A Barry, Guillaume Robichaud, David C Muddiman
Trace evidence is a significant portion of forensic cases. Textile fibers are a common form of trace evidence that are gaining importance in criminal cases. Currently, qualitative techniques that do not yield structural information are primarily used for fiber analysis, but mass spectrometry is gaining an increasing role in this field. Mass spectrometry yields more quantitative structural information about the dye and polymer that can be used for more conclusive comparisons. Matrix-assisted laser desorption electrospray ionization (MALDESI) is a hybrid ambient ionization source being investigated for use in mass spectrometric fiber analysis...
January 2015: Analytical and Bioanalytical Chemistry
https://www.readbyqxmd.com/read/24744212/mapping-antiretroviral-drugs-in-tissue-by-ir-maldesi-msi-coupled-to-the-q-exactive-and-comparison-with-lc-ms-ms-srm-assay
#12
Jeremy A Barry, Guillaume Robichaud, Mark T Bokhart, Corbin Thompson, Craig Sykes, Angela D M Kashuba, David C Muddiman
This work describes the coupling of the IR-MALDESI imaging source with the Q Exactive mass spectrometer. IR-MALDESI MSI was used to elucidate the spatial distribution of several HIV drugs in cervical tissues that had been incubated in either a low or high concentration. Serial sections of those analyzed by IR-MALDESI MSI were homogenized and analyzed by LC-MS/MS to quantify the amount of each drug present in the tissue. By comparing the two techniques, an agreement between the average intensities from the imaging experiment and the absolute quantities for each drug was observed...
December 2014: Journal of the American Society for Mass Spectrometry
https://www.readbyqxmd.com/read/24385399/ir-maldesi-mass-spectrometry-imaging-of-biological-tissue-sections-using-ice-as-a-matrix
#13
Guillaume Robichaud, Jeremy A Barry, David C Muddiman
Infrared matrix-assisted laser desorption electrospray ionization (IR-MALDESI) mass spectrometry imaging of biological tissue sections using a layer of deposited ice as an energy-absorbing matrix was investigated. Dynamics of plume ablation were first explored using a nanosecond exposure shadowgraphy system designed to simultaneously collect pictures of the plume with a camera and collect the Fourier transform ion cyclotron resonance FT-ICR mass spectrum corresponding to that same ablation event. Ablation of fresh tissue analyzed with and without using ice as a matrix were compared using this technique...
March 2014: Journal of the American Society for Mass Spectrometry
https://www.readbyqxmd.com/read/23715870/mass-recalibration-of-ft-icr-mass-spectrometry-imaging-data-using-the-average-frequency-shift-of-ambient-ions
#14
Jeremy A Barry, Guillaume Robichaud, David C Muddiman
Achieving and maintaining high mass measurement accuracy (MMA) throughout a mass spectrometry imaging (MSI) experiment is vital to the identification of the observed ions. However, when using FTMS instruments, fluctuations in the total ion abundance at each pixel due to inherent biological variation in the tissue section can introduce space charge effects that systematically shift the observed mass. Herein we apply a recalibration based on the observed cyclotron frequency shift of ions found in the ambient laboratory environment, polydimethylcyclosiloxanes (PDMS)...
July 2013: Journal of the American Society for Mass Spectrometry
https://www.readbyqxmd.com/read/23237031/direct-analysis-of-textile-fabrics-and-dyes-using-infrared-matrix-assisted-laser-desorption-electrospray-ionization-mass-spectrometry
#15
Kristin H Cochran, Jeremy A Barry, David C Muddiman, David Hinks
The forensic analysis of textile fibers uses a variety of techniques from microscopy to spectroscopy. One such technique that is often used to identify the dye(s) within the fiber is mass spectrometry (MS). In the traditional MS method, the dye must be extracted from the fabric and the dye components are separated by chromatography prior to mass spectrometric analysis. Direct analysis of the dye from the fabric allows the omission of the lengthy sample preparation involved in extraction, thereby significantly reducing the overall analysis time...
January 15, 2013: Analytical Chemistry
https://www.readbyqxmd.com/read/23208743/infrared-matrix-assisted-laser-desorption-electrospray-ionization-ir-maldesi-imaging-source-coupled-to-a-ft-icr-mass-spectrometer
#16
Guillaume Robichaud, Jeremy A Barry, Kenneth P Garrard, David C Muddiman
Mass spectrometry imaging (MSI) allows for the direct monitoring of the abundance and spatial distribution of chemical compounds over the surface of a tissue sample. This technology has opened the field of mass spectrometry to numerous innovative applications over the past 15 years. First used with SIMS and MALDI MS that operate under vacuum, interest has grown for mass spectrometry ionization sources that allow for effective imaging but where the analysis can be performed at ambient pressure with minimal or no sample preparation...
January 2013: Journal of the American Society for Mass Spectrometry
https://www.readbyqxmd.com/read/22095501/global-optimization-of-the-infrared-matrix-assisted-laser-desorption-electrospray-ionization-ir-maldesi-source-for-mass-spectrometry-using-statistical-design-of-experiments
#17
Jeremy A Barry, David C Muddiman
Design of experiments (DOE) is a systematic and cost-effective approach to system optimization by which the effects of multiple parameters and parameter interactions on a given response can be measured in few experiments. Herein, we describe the use of statistical DOE to improve a few of the analytical figures of merit of the infrared matrix-assisted laser desorption electrospray ionization (IR-MALDESI) source for mass spectrometry. In a typical experiment, bovine cytochrome c was ionized via electrospray, and equine cytochrome c was desorbed and ionized by IR-MALDESI such that the ratio of equine:bovine was used as a measure of the ionization efficiency of IR-MALDESI...
December 15, 2011: Rapid Communications in Mass Spectrometry: RCM
https://www.readbyqxmd.com/read/20857437/continuous-flow-infrared-matrix-assisted-laser-desorption-electrospray-ionization-mass-spectrometry
#18
Fan Huang, Kermit K Murray
Continuous flow infrared matrix-assisted laser desorption electrospray ionization (CF IR MALDESI) mass spectrometry was demonstrated for the on-line analysis of liquid samples. Samples in aqueous solution were flowed through a 50 µm i.d. fused-silica capillary at a flow rate of 1-6 µL/min. As analyte aqueous solution flowed through the capillary, a liquid sample bead formed at the capillary tip. A pulsed infrared optical parametric oscillator (OPO) laser with wavelength of 2.94 µm and a 20 Hz repetition rate was focused onto the capillary tip for sample desorption and ablation...
October 15, 2010: Rapid Communications in Mass Spectrometry: RCM
https://www.readbyqxmd.com/read/20419234/study-of-the-ionization-mechanism-in-hybrid-laser-based-desorption-techniques
#19
R Brent Dixon, David C Muddiman
In order to study the ionization mechanism in MALDESI, the RASTIR source was implemented to separate in space the laser desorption event from the intersecting electrospray ionization beam. Deuterated solvents were electrosprayed from the RASTIR source which resulted in a near complete shift from [M + H(+)](1+) to [M + D(+)](1+) of the monoisotopic peak for reserpine. The purpose of these experiments is to test the hypothesis that the primary ionization pathway in MALDESI is through interaction of the laser-desorbed neutral species with the intersecting electrospray ionization beam...
May 2010: Analyst
https://www.readbyqxmd.com/read/19185512/intact-and-top-down-characterization-of-biomolecules-and-direct-analysis-using-infrared-matrix-assisted-laser-desorption-electrospray-ionization-coupled-to-ft-icr-mass-spectrometry
#20
Jason S Sampson, Kermit K Murray, David C Muddiman
We report the implementation of an infrared laser onto our previously reported matrix-assisted laser desorption electrospray ionization (MALDESI) source with ESI post-ionization yielding multiply charged peptides and proteins. Infrared (IR)-MALDESI is demonstrated for atmospheric pressure desorption and ionization of biological molecules ranging in molecular weight from 1.2 to 17 kDa. High resolving power, high mass accuracy single-acquisition Fourier transform ion cyclotron resonance (FT-ICR) mass spectra were generated from liquid- and solid-state peptide and protein samples by desorption with an infrared laser (2...
April 2009: Journal of the American Society for Mass Spectrometry
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