We herein report the optimization and application of silver cationization (Ag) in combination with laser desorption ionization (LDI) ultrahigh-resolution mass spectrometry (UHR-MS) to determine the structures of the sulfur-containing compounds present in heavy crude oil. A number of sulfur-containing model compounds were used to optimize the positive-ion mode LDI-MS conditions in the presence of a silver-complexing agent. Under the optimized LDI conditions, sulfur-rich heavy oil fractions were treated with the silver salt, where Ag coordinated with the sulfur atoms to speciate the sulfur species. The obtained results suggested that benzothiophenic, naphtheno-non-aromatic sulfides, and non-aromatic thiols were the major components present in the analyzed oil sample. Graphical abstract.
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http://dx.doi.org/10.1007/s00216-019-02272-5 | DOI Listing |
Alzheimers Dement
December 2024
Dementia Research Centre, UCL Queen Square Institute of Neurology, London, United Kingdom.
Background: Knowledge of the chemical composition of amyloid plaques and tau tangles at the earlier stages of Alzheimer's disease (AD) pathology is sparse. This is due to limited access to human brain during life and at the earlier stages of AD pathophysiology and technical limitations in quantifying amyloid and tau species at a subcellular level. Understanding the chemical composition of plaques and tangles, how rapidly they grow and what factors drive growth is important for developing and refining therapeutics.
View Article and Find Full Text PDFAlzheimers Dement
December 2024
Tokyo Metropolitan Geriatric Hospital and Institute of Gerontology, Itabashi-ku, Tokyo, Japan.
Background: Although amyloid deposition in brain is one of the hallmark pathological features of Alzheimer's disease (AD), the upstream events and its molecular environment in AD brain remain largely unknown. Recent advances in analytical methods such as mass spectrometry can provide the cutting-edge tools to unveil the AD pathogenesis at molecular and atomic level.
Method: In order to gain the comprehensive information about AD pathology at molecular level, postmortem brain sections of AD patients were analyzed by the hybrid molecular imaging methods composed of the conventional histological analyses, matrix assisted laser desorption ionization mass spectrometry imaging (MALDI-MSI) for small molecules, laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) imaging for metals, and particle induced X-ray emission (PIXE) imaging for elements.
Anal Chem
January 2025
Key Laboratory of Advanced Mass Spectrometry and Molecular Analysis of Zhejiang Province, Institute of Mass Spectrometry, School of Material Science and Chemical Engineering, Ningbo University, Ningbo 315211, China.
Sialic acids are the terminal units of glycans in glycoproteins or glycolipids. The determination of sialic acids in glycoconjugates is crucial since they regulate essential biological functions and have a significant nutritional value. To achieve a specific and high-throughput in situ determination of sialic acids in glycoconjugates, a laser-desorption/ionization mass spectrometry (LDI-MS)-based strategy is reported by integrating chemoselective labeling and laser-cleavable mass tagging.
View Article and Find Full Text PDFTunis Med
December 2024
Faculty of Medicine and Pharmacy, Mohammed V University in Rabat, Morocco.
Introduction: Bloodstream infections are serious conditions requiring precise bacterial identification for effective treatment. Traditional culture-based methods, while reliable, are time-consuming. The direct identification method by MALDI-TOF MS promises rapid and accurate identification directly from positive blood cultures.
View Article and Find Full Text PDFElectrophoresis
January 2025
National Institute for Nuclear, Chemical and Biological Protection, Kamenna, Czech Republic.
Timely identification of highly pathogenic bacteria is crucial for efficient mitigation of the connected harmful health effects. Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) of intact cells enables fast identification of the microorganisms based on their mass spectrometry protein fingerprint profiles. However, the MALDI-TOF MS examination must be preceded by a time-demanding cultivation of the native bacteria to isolate representative cell samples to obtain indicative fingerprints.
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