Showing papers in "Journal of the American Society for Mass Spectrometry in 2009"

TL;DR: Ambient mass spectrometry—mass spectrometric analysis with no or minimal effort for sample preparation—has experienced a very rapid development during the last 5 years, with many different methods now available for ionization.

TL;DR: Four compounds were identified as α-glucosidase inhibitors in the HLFE, and their structures were confirmed to be quercetin-3-O-rha- (1-4)-glc-rha and C-glycosylflavones by high-resolution sustained off resonance irradiation collision-induced dissociation (SORI-CID) data obtained by Fourier transform ion cyclotron resonance mass spectrometry (FTICR MS).

TL;DR: In this article, the authors used a single stage Orbitrap with resolving power settings varying from 10,000 to 100,000 (FWHM) for consistent and reliable mass assignment of analytes at low levels in complex matrices.

TL;DR: The consequences of collisionally activating protein complexes are illustrated through ion mobility mass spectrometry measurements and discussed in the context of the current literature to address outstanding questions and frontier challenges.

TL;DR: Findings highlight the additional conformational stability of protein ions in the gas phase resulting from ligand binding in the presence and absence of bound ligands.

TL;DR: In this study, a prototype benchtop Orbitrap-based mass analyzer was used to collect both quantitative and qualitative data from human microsomal incubation samples as well as rat plasma from pharmacokinetic studies, and the ability to perform highly selective quantitative analysis while simultaneously characterizing metabolites from both in vitro and in vivo studies is discussed.

TL;DR: While allowing analysis of intact proteins without a theoretical upper mass limit, the Orbitrap mass analyzer demonstrates reduced resolving power as ion mass increases even at a constant mass-to-charge ratio, it is shown that this effect comes from the effects of ion scattering on background gas molecules.

TL;DR: Results suggest that a charged droplet pick-up mechanism is responsible for desorption and ionization of liquid samples by DESI, which could have potentials in bioanalytical and forensic analysis.

TL;DR: A new design of the Orbitrap™ mass analyzer is presented that achieves higher frequencies of ion oscillations and hence higher resolving power over fixed acquisition time by decreasing the gap between the inner and outer Orbitrap electrodes, thus providing higher field strength for a given voltage.

TL;DR: Of all the sorbents used in the study, Clean Screen DAU performed best for extraction of the analytes from urine, and the study sought to demonstrate that it is possible to quantify the analyte of interest using a DART source when an internal standard is used.

TL;DR: Increased multiple charging of native proteins and noncovalent protein complexes is observed in electrospray ionization (ESI) mass spectra obtained from nondenaturing protein solutions containing up to 1% m-nitrobenzyl alcohol (m-NBA).

TL;DR: The sequence coverage (the number of cleavages) was greatly increased after reduction of disulfide bonds and HPLC/MS/MS analysis of light and heavy chains using collision-induced dissociation in the ion trap of the LTQ-Orbitrap.

TL;DR: The results of this work suggest that ETD of intact protein ions is not accompanied by detectable hydrogen scrambling and can be used in tandem with HDX to probe protein conformation in solution.

TL;DR: This critical insight is addressed through the discussion of a number of aspects of MS imaging technology and sample preparation that strongly determine the outcome of imaging MS experiments.

TL;DR: The preeminence of ion traps for detail analysis was further demonstrated by resolving three new isomers within the Man5 glycomer summing to the six previously unreported structures in this glycoprotein.

TL;DR: This study demonstrates that even when the targeted sample preparation from conventional LC-MS/MS is applied to UPLC with full-scan accurate mass MS, false compliant results can be obtained when the mass resolving power of the MS is insufficient to separate analyte ions from isobaric co-eluting sample matrix ions.

TL;DR: One of the conclusions from these experiments is that THF and 1,4-dioxane are inappropriate to be used as solvents and/or dopants for LC/NI-APPI-MS due to their high reactivity with source basic ions, leading to many reactant ions in the background.

TL;DR: The findings demonstrate that the discharges used by FAPA and DART are fundamentally different and should have different optimal applications for ambient desorption/ionization mass spectrometry (ADI-MS).

TL;DR: A method for rapid analysis of glycosylation profile of the therapeutic monoclonal antibody trastuzumab from different production batches using electrospray quadrupole ion-mobility time-of-flight mass spectrometry (ESI-Q-IM-TOF).

TL;DR: Although a record limit of detection of 0.2 × 10−12 atmospheres is found for explosives such as PETN and 0.4 ppt for TNT, this still implies the need for some 108–109 vapor molecules/s for positive identification of explosives.

TL;DR: A three-dimensional mass spectral imaging technique was developed to examine distribution patterns of multiple neuropeptide families and lipids in the brain of the crab Cancer borealis, suggesting their potential different functional roles in the nervous system.

TL;DR: Ten natural products ranging in molecular weight from 639 to 1663 Da were measured on an LTQ/Orbitrap mass spectrometer and several compounds with prominent doubly charged ions allowed comparison of spectral accuracies of singly-versus doubly-charged ions.

TL;DR: Three of the four classes of biological macromolecules have been ionized and detected using MALDESI with minimal sample preparation and Sequencing of O-linked glycans, cleaved from mucin using reductive β-elimination chemistry, is also demonstrated.

TL;DR: Optimization of various instrument and post-acquisition parameters that collectively provide for quantification of iTRAQ-labeled phosphorylated peptides isolated from complex cell lysates are described and appropriate parameterization of collision energy as a function of precursor m/z and z is indicated.

TL;DR: A sharply improved two-dimensional separation is presented to drive reproducible and robust fractionation before top-down mass spectrometry of complex mixtures and a variety of other protein separation and/or characterization approaches.

TL;DR: An integrated software platform titled HD Desktop designed specifically to enhance the analysis of hydrogen/deuterium exchange (HDX) mass spectrometry data is described, which provides an efficient and manageable workflow for HDX data analysis.

TL;DR: It was determined that both the proton affinity and pKa of the cation have a large effect on the ionic liquid matrices’ ability to effectively ionize the analyte.

TL;DR: The results indicate that the enhanced charging upon addition of m-NBA to aqueous electrospray solutions is a result of droplet heating owing to the high boiling point ofm-NBA, which results in a change in the higher-order structure and/or dissociation of the complexes.

TL;DR: A newly developed high-throughput desorption electrospray ionization (DESI) source was characterized in terms of its performance in quantitative analysis.

TL;DR: Comparison of the IRMPD spectrum of b2+ to spectra predicted by density functional theory provides compelling evidence for an oxazolone structure protonated at the oxAZolone N-atom.