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Ionization Mass Spectrometric Analysis (ionization + mass_spectrometric_analysis)
Selected AbstractsThe effect of sodium dodecyl sulfate and anion-exchange silica gel on matrix-assisted laser desorption/ionization mass spectrometric analysis of proteinsRAPID COMMUNICATIONS IN MASS SPECTROMETRY, Issue 11 2009Miwako Asanuma Sodium dodecyl sulfate (SDS), an anionic surfactant, is widely used in peptide and protein sample preparation. When the sample is analyzed by matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS), this surfactant can often cause signal suppression. We have previously reported an on-probe sample preparation method using a suspension of anion-exchange silica gel and sinapinic acid (i.e., gel-SA suspension) as a matrix, thereby greatly improving the MALDI signal detection of the protein solutions containing SDS. In this study, we found that a certain amount of SDS enhanced the MALDI signal intensity for protein samples. This effect was also observed when using sodium decyl sulfate and sodium tetradecyl sulfate instead of SDS. Furthermore, this on-probe sample preparation method using both SDS and the gel-SA suspension improved the detection limit of protein samples in the MALDI-MS analysis by about ten-fold as compared to that of protein samples without SDS and the gel-SA suspension. This method can be applied not only to the MALDI-MS analysis of samples containing SDS, but also to the examination of proteins at femtomole levels or insoluble proteins such as membrane proteins. Copyright © 2009 John Wiley & Sons, Ltd. [source] Influence of mobile phase composition on the high-performance liquid chromatographic/electrospray ionization mass spectrometric analysis of 11-nor-9-carboxy-,9 -tetrahydrocannabinol (THC-COOH) and its glucuronide in urineJOURNAL OF MASS SPECTROMETRY (INCORP BIOLOGICAL MASS SPECTROMETRY), Issue 4 2004[source] Shotgun lipidomics: Electrospray ionization mass spectrometric analysis and quantitation of cellular lipidomes directly from crude extracts of biological samplesMASS SPECTROMETRY REVIEWS, Issue 3 2005Xianlin Han Abstract Lipidomics, after genomics and proteomics, is a newly and rapidly expanding research field that studies cellular lipidomes and the organizational hierarchy of lipid and protein constituents mediating life processes. Lipidomics is greatly facilitated by recent advances in, and novel applications of, electrospray ionization mass spectrometry (ESI/MS). In this review, we will focus on the advances in ESI/MS, which have facilitated the development of shotgun lipidomics and the utility of intrasource separation as an enabling strategy for utilization of 2D mass spectrometry in shotgun lipidomics of biological samples. The principles and experimental details of the intrasource separation approach will be extensively discussed. Other ESI/MS approaches towards the quantitative analyses of global cellular lipidomes directly from crude lipid extracts of biological samples will also be reviewed and compared. Multiple examples of lipidomic analyses from crude lipid extracts employing these approaches will be given to show the power of ESI/MS techniques in lipidomics. Currently, modern society is plagued by the sequelae of lipid-related diseases. It is our hope that the integration of these advances in multiple disciplines will catalyze the development of lipidomics, and such development will lead to improvements in diagnostics and therapeutics, which will ultimately result in the extended longevity and an improved quality of life for humankind. © 2004 Wiley Periodicals, Inc., Mass Spec Rev 24:367,412, 2005 [source] Desorption electrospray ionization mass spectrometric analysis of organophosphorus chemical warfare agents using ion mobility and tandem mass spectrometryRAPID COMMUNICATIONS IN MASS SPECTROMETRY, Issue 11 2010Paul A. D'Agostino Desorption electrospray ionization mass spectrometry (DESI-MS) has been applied to the direct analysis of sample media for target chemicals, including chemical warfare agents (CWA), without the need for additional sample handling. During the present study, solid-phase microextraction (SPME) fibers were used to sample the headspace above five organophosphorus CWA, O -isopropyl methylphosphonofluoridate (sarin, GB), O -pinacolyl methylphosphonofluoridate (soman, GD), O -ethyl N,N -dimethyl phosphoramidocyanidate (tabun, GA), O -cyclohexyl methylphosphonofluoridate (cyclohexyl sarin, GF) and O -ethyl S-2-diisopropylaminoethyl methyl phosphonothiolate (VX) spiked into glass headspace sampling vials. Following sampling, the SPME fibers were introduced directly into a modified ESI source, enabling rapid and safe DESI of the toxic compounds. A SYNAPT HDMSÔ instrument was used to acquire time-aligned parallel (TAP) fragmentation data, which provided both ion mobility and MSn (n,=,2 or 3) data useful for the confirmation of CWA. Unique ion mobility profiles were acquired for each compound and characteristic product ions of the ion mobility separated ions were produced in the TriwaveÔ transfer collision region. Up to six full scanning MSn spectra, containing the [M,+,H]+ ion and up to seven diagnostic product ions, were acquired for each CWA during SPME fiber analysis. A rapid screening approach, based on the developed methodology, was applied to several typical forensic media, including Dacron sampling swabs spiked with 5,µg of CWA. Background interference was minimal and the spiked CWA were readily identified within one minute on the basis of the acquired ion mobility and mass spectrometric data. Copyright © 2010 Crown in the right of Canada. Published by John Wiley & Sons, Ltd. [source] Reduction of in-source collision-induced dissociation and thermolysis of sulopenem prodrugs for quantitative liquid chromatography/electrospray ionization mass spectrometric analysis by promoting sodium adduct formationRAPID COMMUNICATIONS IN MASS SPECTROMETRY, Issue 20 2008Chad E. Wujcik Six chromatographically resolved sulopenem prodrugs were monitored for their potential to undergo both in-source collision-induced dissociation (CID) and thermolysis. Initial Q1 scans for each prodrug revealed the formation of intense [Prodrug2,+,H]+, [Prodrug2,+,Na]+, [Prodrug,+,Na]+, and [Sulopenem,+,Na]+ ions. Non-adduct-associated sulopenem ([Sulopenem,+,H]+) along with several additional lower mass ions were also observed. Product ion scans of [Prodrug3,+,Na]+ showed the retention of the sodium adduct in the collision cell continuing down to opening of the , -lactam ring. In-source CID and temperature experiments were conducted under chromatographic conditions while monitoring several of the latter ion transitions (i.e., adducts, dimers and degradants/fragments) for a given prodrug. The resulting ion profiles indicated the regions of greatest stability for temperature and declustering potential (DP) that provided the highest signal intensity for each prodrug and minimized in-source degradation. The heightened stability of adduct ions, relative to their appropriate counterpart (i.e., dimer to dimer adduct and prodrug to prodrug adduct ions), was observed under elevated temperature and DP conditions. The addition of 100,µM sodium to the mobile phase further enhanced the formation of these more stable adduct ions, yielding an optimal [Prodrug,+,Na]+ ion signal at temperatures from 400 to 600°C. A clinical liquid chromatography/tandem mass spectrometry (LC/MS/MS) assay for sulopenem prodrug PF-04064900 in buffered whole blood was successfully validated using sodium-fortified mobile phase and the [PF-04064900,+,Na]+ ion for quantitation. A conservative five-fold increase in sensitivity from previously validated preclinical assays using the [PF-04064900,+,H]+ precursor ion was achieved. Copyright © 2008 John Wiley & Sons, Ltd. [source] Ion-pairing reversed-phase liquid chromatography/electrospray ionization mass spectrometric analysis of 76 underivatized amino acids of biological interest: a new tool for the diagnosis of inherited disorders of amino acid metabolismRAPID COMMUNICATIONS IN MASS SPECTROMETRY, Issue 12 2005Monique Piraud Seventy-six molecules of biological interest for the diagnosis of inherited disorders of amino acids (AA) metabolism have previously been demonstrated to be detectable in electrospray ionization tandem mass spectrometry (ESI-MS/MS) positive mode without derivatization. Reversed-phase liquid chromatography (RPLC) separation on different C18 columns using various perfluorinated carboxylic acids as ion-pairing agents has been found suitable for coupling with MS/MS, and for the separation of AA. A new procedure was optimized in order to replace the usual ion-exchange chromatographic, post-column ninhydrin derivatization, time-consuming routine method. This procedure allowed an adequate separation of all the molecules from other known interfering compounds, and a throughput of two samples per hour. Quantification limits for each molecule were found to be compatible with their measurement in plasma and urine. We validated the qualitative part of the method by analyzing plasma and urine samples from patients affected with several inherited disorders of AA metabolism. We validated the quantification of 16 AA using their stable isotopes as internal standard. The calibration curves were linear over the range 0,3,mM. The quantitative results obtained with the new method on 105 plasma and 99 urine samples were in good agreement with those obtained by the established routine method. Spiking experiments and precision results were also satisfactory. Copyright © 2005 John Wiley & Sons, Ltd. [source] Nitrogen purity influences the occurrence of As+ ions in high-performance liquid chromatography/electrospray ionization mass spectrometric analysis of four common arsenosugarsRAPID COMMUNICATIONS IN MASS SPECTROMETRY, Issue 7 2003Doris Kuehnelt High-performance liquid chromatography coupled to electrospray ionization mass spectrometry (HPLC/ESI-MS) can provide both elemental and molecular information and, therefore, is a very useful tool for the identification of arsenic compounds. When a method for the identification of four arsenosugars was employed in our laboratory with an HPLC/ESI-MS system equipped with a Whatman model 75-72 nitrogen generator, a signal at m/z 75 (As+) could not be observed. When the HPLC/ESI-MS system was operated with nitrogen 5.0 (nitrogen of a purity of at least 99.999%) all four arsenosugars gave a signal at m/z 75. Because of this observation the influence of the quality of the nitrogen drying gas on the fragmentation of the four arsenosugars was systematically investigated. Standard solutions containing the four arsenosugars (0.5 ng As each) were separated on an anion-exchange column and detected with ESI-MS in the positive ion mode by monitoring the signals for [M+H]+, m/z 237, 91, and 75. Nitrogen with defined oxygen concentrations was used as drying gas. The purity of the nitrogen ranged from 99 to 99.999% (10,400 to 10 ppm oxygen impurity). The nitrogen with 99% purity gave no signal at m/z 75, but signals were obtained at m/z 91, 237, and for [M+H]+. When higher purity nitrogen (99.9%) was used, a signal was obtained at m/z 75, which accounted for 0.8,1.1% (depending on the kind of arsenosugar) of the sum of the signals for m/z 75, 91, 237 and [M+H]+. As the level of oxygen in the nitrogen decreased, the m/z 75 signal increased to 2.0,3.1%. This was accompanied by a concomitant decrease in the m/z 91 signal from 5.2,6.6% to 0.7,1.5%, whereas the signals for [M+H]+ and m/z 237 were essentially unchanged. Signals at m/z 75 with intensities comparable with those observed for the 99.9% pure nitrogen were also obtained for all the arsenosugars when the HPLC/ESI-MS system was operated with a Domnick Hunter Nitrox UHPLCMS18 nitrogen generator. Dimethylarsinic acid, arsenobetaine, trimethylarsine oxide, arsenocholine and the tetramethylarsonium cation also gave no signal at m/z 75 when they were analyzed with the Whatman model 75-72 nitrogen generator, but clear signals at m/z 75 were observed with the Domnick Hunter Nitrox UHPLCMS18 nitrogen generator. A nitrogen quality of at least 99.9% is required to obtain elemental information (m/z 75) when arsenic compounds are investigated by HPLC/ESI-MS. Molecular and elemental information from one chromatographic run is a valuable tool for the characterization of unknown arsenic compounds. Copyright © 2003 John Wiley & Sons, Ltd. [source] | ||||||||||