The Experts below are selected from a list of 49182 Experts worldwide ranked by ideXlab platform
C. Logan Mackay - One of the best experts on this subject based on the ideXlab platform.
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Matrix-free mass spectrometric imaging using Laser Desorption ionisation Fourier transform ion cyclotron resonance mass spectrometry
Rapid Communications in Mass Spectrometry, 2011Co-Authors: Richard J.a. Goodwin, Stefan K. Weidt, Patrick R. R. Langridge-smith, Andrew R. Pitt, Michael P. Barrett, David Harrison, C. Logan MackayAbstract:Mass spectrometry imaging (MSI) is a powerful tool in metabolomics and proteomics for the spatial localization and identification of pharmaceuticals, metabolites, lipids, peptides and proteins in biological tissues. However, sample preparation remains a crucial variable in obtaining the most accurate distributions. Common washing steps used to remove salts, and solvent-based matrix application, allow analyte spreading to occur. Solvent-free matrix applications can reduce this risk, but increase the possibility of ionisation bias due to matrix adhesion to tissue sections. We report here the use of matrix-free MSI using Laser Desorption ionisation performed on a 12 T Fourier transform ion cyclotron resonance (FTICR) mass spectrometer. We used unprocessed tissue with no post-processing following thaw-mounting on matrix-assisted Laser Desorption ionisation (MALDI) indium-tin oxide (ITO) target plates. The identification and distribution of a range of phospholipids in mouse brain and kidney sections are presented and compared with previously published MALDI time-of-flight (TOF) MSI distributions.
Jentaie Shiea - One of the best experts on this subject based on the ideXlab platform.
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applications of electrospray Laser Desorption ionization mass spectrometry for document examination
Rapid Communications in Mass Spectrometry, 2010Co-Authors: Sy-chyi Cheng, Yu-shan Lin, Ming-zong Huang, Jentaie ShieaAbstract:We have employed electrospray Laser Desorption ionization mass spectrometry (ELDI-MS) to rapidly characterize certain classes of compounds--the inks within the characters made by inks and inkjet printer on regular paper and the chemical compounds within thermal papers. This ELDI-MS approach allowed the ink and paper samples to be distinguished in terms of their chemical compositions. Sample pretreatment was unnecessary and the documents were practically undamaged after examination. The ink chemicals on the documents were desorbed through Laser irradiation (sampling spot area: <100 microm(2)); the desorbed molecules then entered an electrospray plume--prepared from an acidic methanol/water solution (50%)--where they became ionized through fusion or ion-molecule reactions with the charged solvent species and droplets in the plume.
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using electrospray assisted Laser Desorption ionization mass spectrometry to characterize organic compounds separated on thin layer chromatography plates
Analytical Chemistry, 2007Co-Authors: Shuyao Lin, Minzong Huang, Huichiu Chang, Jentaie ShieaAbstract:Electrospray-assisted Laser Desorption/ionization (ELDI), an ionization method that combines Laser Desorption and electrospray ionization (ESI), can be used under ambient conditions to characterize organic compounds (including FD&C dyes, amines, extracts of a drug tablet) separated in the central track on a thin-layer chromatography (TLC) plate coated with either reversed-phase C18 particles or normal-phase silica gel. After drying, the TLC plate was placed on an acrylic sample holder set in front of the sampling skimmer of an ion trap mass analyzer. The chemicals at the center of the TLC plate were analyzed by pushing the sample holder into the path of a Laser beam with a syringe pump. The molecules in the sample spot were desorbed by continuously irradiating the surface of the TLC plate with a pulsed nitrogen Laser. Then, the desorbed sample molecules entered an ESI plume where they were ionized through the reactions with the charged species (including protons, hydronium ions and their cluster ions, sol...
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direct protein detection from biological media through electrospray assisted Laser Desorption ionization mass spectrometry
Journal of Proteome Research, 2006Co-Authors: Minzong Huang, Hsiujung Hsu, Jenyih Lee, Jingyueh Jeng, Jentaie ShieaAbstract:We report here using a novel technology-electrospray-assisted Laser Desorption ionization (ELDI)/mass spectrometry-for the rapid and sensitive detection of the major proteins that exist in dried biological fluids (e.g., blood, tears, saliva, serum), bacterial cultures, and tissues (e.g., porcine liver and heart) under ambient conditions. This technique required essentially no sample pretreatment. The proteins in the samples were desorbed using a pulsed nitrogen Laser without the assistance of an organic matrix. The desorbed protein molecules were then post-ionized through their fusion into the charged solvent droplets produced from the electrospray of an acidic methanol solution; electrospray ionization (ESI) proceeded from the newly formed droplets to generate the ESI-like protein ions. This new ionization approach combines some of the features of electrospray ionization with those of matrix-assisted Laser Desorption ionization (MALDI), that is, sampling of a solid surface with spatial resolution, generating ESI-like mass spectra of the desorbed proteins, and operating under ambient conditions.
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electrospray assisted Laser Desorption ionization mass spectrometry for direct ambient analysis of solids
Rapid Communications in Mass Spectrometry, 2005Co-Authors: Jentaie Shiea, Minzon Huang, Chenghui Yuan, Iwona B Beech, Jan SunnerAbstract:A new method of electrospray-assisted Laser Desorption/ionization (ELDI) mass spectrometry, which combines Laser Desorption with post-ionization by electrospray, was applied to rapid analysis of solid materials under ambient conditions. Analytes were desorbed from solid metallic and insulating substrata using a pulsed nitrogen Laser. Post-ionization produced high-quality mass spectra characteristic of electrospray, including protein multiple charging. For the first time, mass spectra of intact proteins were obtained using Laser Desorption without adding a matrix. Bovine cytochrome c and an illicit drug containing methaqualone were chosen in this study to demonstrate the applicability of ELDI to the analysis of proteins and synthetic organic compounds.
Huantsung Chang - One of the best experts on this subject based on the ideXlab platform.
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accurate quantitation of glutathione in cell lysates through surface assisted Laser Desorption ionization mass spectrometry using gold nanoparticles
Nanomedicine: Nanotechnology Biology and Medicine, 2010Co-Authors: Chengkang Chiang, Yangwei Lin, Wen Tsen Chen, Huantsung ChangAbstract:Abstract We developed a method for the determination of three aminothiols—cysteine, glutathione (GSH), and homocysteine—using surface-assisted Laser Desorption/ionization mass spectrometry (SALDI-MS). The analytes were first captured using the unmodified 14-nm gold nanoparticles; N-2-mercaptopropionylglycine–modified gold nanoparticles serving as internal standard were sequentially added, and then the sample was analyzed using SALDI-MS. This approach provided good quantitative linearity of the three analytes (R2 = ∼0.99), with good reproducibility (relative standard deviations: From the Clinical Editor This paper reports the development of a surface assisted Laser Desorption/ionization mass spectrometry method to precisely determine aminothiols-cysteine (Cys), glutathione (GSH), and homocysteine (HCys)
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nanomaterial based surface assisted Laser Desorption ionization mass spectrometry of peptides and proteins
Journal of the American Society for Mass Spectrometry, 2010Co-Authors: Chengkang Chiang, Ni Chen Chiang, Zonghong Lin, Guoyu Lan, Yangwei Lin, Huantsung ChangAbstract:We have investigated six nanomaterials for their applicability as surfaces for the analyses of peptides and proteins using surface-assisted Laser Desorption/ionization mass spectrometry (SALDI-MS). Gold nanoparticles (NPs) were useful nanomateriais for small analytes (e.g., glutathione); Pt nanosponges and Fe3O4 NPs were efficient nanomaterials for proteins, with an upper detectable mass limit of ca. 25 kDa. Nanomateriais have several advantages over organic matrices, including lower limits of detection for small analytes and lower batch-to-batch variations (fewer problems associated with “sweet spois”), when used in Laser Desorption/ionization mass spectrometry.
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detection of proteins and protein ligand complexes using hgte nanostructure matrixes in surface assisted Laser Desorption ionization mass spectrometry
Analytical Chemistry, 2010Co-Authors: Chengkang Chiang, Yangwei Lin, Wen Tsen Chen, Zusing Yang, Hanjia Lin, Huantsung ChangAbstract:We have analyzed peptides, proteins, and protein−drug complexes through surface-assisted Laser Desorption/ionization mass spectrometry (SALDI-MS) using HgTe nanostructures as matrixes. We investiga...
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analysis of adenosine triphosphate and glutathione through gold nanoparticles assisted Laser Desorption ionization mass spectrometry
Analytical Chemistry, 2007Co-Authors: Yufen Huang, Huantsung ChangAbstract:This paper describes the use of aptamer-modified gold nanoparticles (Apt−AuNPs) as selective probes and AuNPs as the surface-assisted Laser Desorption/ionization (SALDI) matrixes for the determination of adenosine triphosphate (ATP) by mass spectrometry (MS). The aptamers were covalently attached to the surface of AuNPs to form Apt−AuNPs that provided selectivity toward ATP. However, Apt−AuNPs are less efficient Laser Desorption/ionization (LDI) matrixes when compared to AuNPs. By using Apt−AuNPs as selective probes and AuNPs as LDI matrixes, the MS approach provided the limit of detection (LOD) for ATP at a signal-to-noise ratio of 3 of 0.48 μM. When compared to conventional organic matrixes (e.g., 2,5-dihydroxybenzoic acid), AuNPs as LDI matrixes provide a number of advantages, including ease of preparation, selectivity, sensitivity, and repeatability. Sequential analysis of ATP and GSH in human cell lysates by SALDI with negative and positive MS modes, respectively, using Apt−AuNPs and AuNPs has been d...
J F Muller - One of the best experts on this subject based on the ideXlab platform.
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evaluation of combined matrix assisted Laser Desorption ionization time of flight and matrix assisted Laser Desorption ionization fourier transform ion cyclotron resonance mass spectrometry experiments for peptide mass fingerprinting analysis
Rapid Communications in Mass Spectrometry, 2011Co-Authors: David Da Silva, Thierry Wasselin, Vincent Carre, Patrick Chaimbault, Lina Bezdetnaya, Benoit Maunit, J F MullerAbstract:Peptide Mass Fingerprinting (PMF) is still of significant interest in proteomics because it allows a large number of complex samples to be rapidly screened and characterized. The main part of post-translational modifications is generally preserved. In some specific cases, PMF suffers from ambiguous or unsuccessful identification. In order to improve its reliability, a combined approach using matrix-assisted Laser Desorption/ionization time-of-flight mass spectrometry (MALDI-TOFMS) and matrix-assisted Laser Desorption/ionization Fourier transform ion cyclotron resonance mass spectrometry (MALDI-FTICRMS) was evaluated. The study was carried out on bovine serum albumin (BSA) digest. The influence of several important parameters (the matrix, the sample preparation method, the amount of the analyte) on the MOWSE score and the protein sequence coverage were evaluated to allow the identification of specific effects. A careful investigation of the sequence coverage obtained by each kind of experiment ensured the detection of specific peptides for each experimental condition. Results highlighted that DHB-FTICRMS and DHB- or CHCA-TOFMS are the most suited combinations of experimental conditions to achieve PMF analysis. The association (convolution) of the data obtained by each of these techniques ensured a significant increase in the MOWSE score and the protein sequence coverage. Copyright © 2011 John Wiley & Sons, Ltd.
Richard J.a. Goodwin - One of the best experts on this subject based on the ideXlab platform.
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Matrix-free mass spectrometric imaging using Laser Desorption ionisation Fourier transform ion cyclotron resonance mass spectrometry
Rapid Communications in Mass Spectrometry, 2011Co-Authors: Richard J.a. Goodwin, Stefan K. Weidt, Patrick R. R. Langridge-smith, Andrew R. Pitt, Michael P. Barrett, David Harrison, C. Logan MackayAbstract:Mass spectrometry imaging (MSI) is a powerful tool in metabolomics and proteomics for the spatial localization and identification of pharmaceuticals, metabolites, lipids, peptides and proteins in biological tissues. However, sample preparation remains a crucial variable in obtaining the most accurate distributions. Common washing steps used to remove salts, and solvent-based matrix application, allow analyte spreading to occur. Solvent-free matrix applications can reduce this risk, but increase the possibility of ionisation bias due to matrix adhesion to tissue sections. We report here the use of matrix-free MSI using Laser Desorption ionisation performed on a 12 T Fourier transform ion cyclotron resonance (FTICR) mass spectrometer. We used unprocessed tissue with no post-processing following thaw-mounting on matrix-assisted Laser Desorption ionisation (MALDI) indium-tin oxide (ITO) target plates. The identification and distribution of a range of phospholipids in mouse brain and kidney sections are presented and compared with previously published MALDI time-of-flight (TOF) MSI distributions.
