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Topic: Mass spectrometry

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In the News (Mon 18 Feb 19)

  Mass spectrometry - Mass Spectrometry Wiki
Mass spectrometry is an analytical technique used to measure the mass-to-charge ratio of w:ions.
The cylindrical ion trap mass spectrometer is a derivative of the quadrupole ion trap mass spectrometer.
A mass spectrometer produces a mass spectrum, which is a plot of the relative abundances of ions as a function of the the ratio of their mass-to-charge values.
mass-spec.lsu.edu /mswiki/index.php/Mass_spectrometry   (3059 words)

 Mass Spectrometry
A mass spectrum will usually be presented as a vertical bar graph, in which each bar represents an ion having a specific mass-to-charge ratio (m/z) and the length of the bar indicates the relative abundance of the ion.
The unit mass resolution is readily apparent in these spectra (note the separation of ions having m/z=39, 40, 41 and 42 in the cyclopropane spectrum).
The mass calculator on the right may be used to calculate the exact mass of a molecule based on its elemental composition.
www.cem.msu.edu /~reusch/VirtualText/Spectrpy/MassSpec/masspec1.htm   (2839 words)

 Protein identification by mass spectrometry
The mass difference, or distance in atomic mass units between the peaks along the spectrum, allows each amino acid (e.g., alinine, arsenine, glycine, or lysine—four of the 20 possible amino acids) to be identified.
During the mid-1980s, the quadrupole ion trap was beginning to emerge as a mass analyzer with interesting characteristics for tandem mass spectrometry.
Mass spectrometry can be used to confirm the presence or absence of a phosphate in a protein.
www.eurekalert.org /features/doe/2001-06/drnl-pib061902.php   (1886 words)

 Thermo Scientific - Proteomics - Mass Spectrometry Introduction
century, mass spectrometry has been used for a wide variety of applications ranging from estimating the masses of elements and their isotopes to small molecule i dentification and characterization to modern day proteomics analysis.
Mass spectrometry involves three basic steps: first the generation of ions, second the separation of ions and third the detection of ions.
Mass spectrometry in proteomics today addresses three broad application areas, identification of individual proteins from a mixture, quantification of proteins in a cell or organism and characterization of proteins to better explain its characteristics.
www.thermo.com /com/cda/resources/resources_detail/1,,36,00.html   (712 words)

 Mass Spectrometry
The central, unifying theme of these applications is the ability to determine rapidly masses ranging from those of small molecules (100 Da) to those of macromolecules (150 kDa) with extraordinary precision (10 ppm).
Mass spectrometry is a well established technique in chemistry, but recently it was recognized that proteins produce a unique “fingerprint” of peptide masses upon digestion with sequence-specific proteases that can be compared to masses predicted from protein databases.
For higher mass ions, those having a higher kinetic energy, reflection lengthens their flight path, increasing the time of flight to the detector.
www.sh.lsuhsc.edu /oor/crf/mass.html   (2143 words)

 Biopharmaceutical Mass Spectrometry glossary taxonomy
A mass spectrometric technique that is used for the analysis of a wide range of biomolecules, such as glycoalkaloids, glycoproteins, polysaccharides, and peptides.
The MALDI-TOF mass spectrometer measures the exact mass of DNA fragments and is capable of accurately predicting the sequence of a DNA fragment based on the molecules mass.
This allows the mass of an intact protein to be used to identify all splicing and post-translational modification, with each assignable to disparate regions on the polypeptide chain from their corresponding fragment mass values.
www.genomicglossaries.com /content/mass_spectrometry.asp   (3119 words)

 i-mass.com : international mass spectrometry web resource
Mass spectrometers act as sensitive chemical warfare detectors to protect troops in war on Iraq...
Dr Toyoda of Osaka University is to be awarded the 2003 Curt Brunnée Award at the forthcoming international conference on mass spectrometry...
Bruker Daltonics have released the Esquire HCT quadrupole ion trap mass spectrometer.
www.i-mass.com   (446 words)

 Mass Spectometry
Atomic spectroscopy and mass spectrometry are important tools for identifying and quantifying trace elements in food products-elements that may be...
John R. Barr and colleagues in a multi-center team effort used a form of mass spectrometry to detect the presence of 'lethal factor,' the key toxin produced...
Fresh data on mass spectrometry are presented in the report ?Low-energy collision-induced fragmentation of negative ions derived from ortho-, meta-,...
www.massspectrometryinfo.com   (377 words)

 MRSEC Shared facilities - Mass Spectrometry
The Mass Spectrometry Facility at the University of Massachusetts was established in September 1997 with the purchase an ion trap mass spectrometer.
The "unlimited" mass range of a time of flight mass spectrometer enables the molecular weight and polydispersity of polymers to be analyzed.
In addition to the well-equipped mass spectrometry facility, two other shared facilities are available for molecular weight determination.
www.pse.umass.edu /mrsec/maspecfac.html   (299 words)

 Mass Spectrometry Facility
The National Bio-Organic, Biomedical Mass Spectrometry Resource, supported by the NIH National Center for Research Resources, provides both scientific and technical expertise and state-of-the-art high-performance, tandem mass spectrometric instrumentation.
The International Symposium on Mass Spectrometry in the Health and Life Sciences is held biennially in San Francisco.
The program brings together world leaders in mass spectrometry instrumentation and methodology development with pioneer researchers in biology, biochemistry, and chemical biology, providing a forum for discussion of how mass spectrometry can best be used to drive knowledge in the life sciences.
donatello.ucsf.edu   (262 words)

 Mass Spectrometry - Base Peak - The web's leading Mass Spectrometry Resource
Ceramic vessels dating from the 13th Century that were unearthed in a vault in a Tuscan church were used as food containers or to cook a variety of foods, including meat, vegetable broths and soups, according to mass spectrometric studies of the residual organic matter.
The performance of a new open air ionisation technique, in which neutral analyte molecules are desorbed from a sample and ionised by extractive electrospray ionisation, has been demonstrated for a variety of food samples including spinach contaminated with bacteria and spoiled meat.
In this FREE tutorial, brought to you by Chromedia, the three key steps of mass spectral interpretation are addressed, namely molecular weight determination, interpretation of observed fragments ions and structure proposal.
www.spectroscopynow.com /coi/cda/home.cda?chId=4   (468 words)

 Open Directory - Science: Chemistry: Analytical: Mass Spectrometry
Introduction to Mass Spectrometry - Definitions and biological applications at Astbury Centre for Structural Molecular Biology, University of Leeds, England.
Mass Spectral Molecular Weight - This site lists mass occurrence probabilities and gives simple rules for upper and lower limits to the molecular weight of an unknown from mass spectral data.
Mass Spectrometry Blog - Web log of MS web sites and other links and items of interest, maintained from Department of Chemistry Louisiana State University.
www.dmoz.org /Science/Chemistry/Analytical/Mass_Spectrometry   (401 words)

  Joerg's Mass Spectrometry Pages
I'm working with mass spectrometry most of my time (and that can really, really be fun!).
Kind, O. Fiehni: Seven Golden Rules for heuristic filtering of molecular formulas obtained by accurate mass spectrometry, BMC Bioinformatics 8 (2007), 105.
AMDIS (Automated Mass spectral Deconvolution and Identification) is a program for MS-Windows that can read data files from different manufacturers, including netCDF.
homepage.sunrise.ch /mysunrise/joerg.hau/sci/index.htm   (2232 words)

 Untitled Document
The main function of the mass analyser is to separate, or resolve, the ions formed in the ionisation source of the mass spectrometer according to their mass-to-charge (m/z) ratios.
The mass profile is dominated by a component of molecular mass 14,305.7 Da, with a series of minor peaks at higher mass, which is usually indicative of salt adducting e.g.
The mass accuracy depends on the type and performance of the analyser of the mass spectrometer, but most modern instruments should be capable of measuring masses to within 0.01% of the molecular mass of the sample, at least up to ca.
www.astbury.leeds.ac.uk /facil/MStut/mstutorial.htm   (5863 words)

 The Science Creative Quarterly » MASS SPECTROMETRY
Development of mass spectrometry began with J.J. Thomson’s vacuum tube, with which, in the early part of the 20th century, he demonstrated the existence of electrons and “positive rays.” Thomson observed that the new technique could also be used by chemists to analyze chemicals.
A basic mass spectrometer consists of three parts: A source in which ions are produced from the chemical substance, an analyzer in which ions are separated according to mass,and a detector, which produces a signal from the separated ions.
Mass spectrometry allows even tiny amounts of a protein to be identified both by its sequence and through database searches of protein fingerprints.
www.scq.ubc.ca /?p=273   (882 words)

 Mass Spectrometry
Mass spectrometry is based on slightly different principles to the other spectroscopic methods.
The physics behind mass spectrometry is that a charged particle passing through a magnetic field is deflected along a circular path on a radius that is proportional to the mass to charge ratio, m/e.
In an electron impact mass spectrometer, a high energy beam of electrons is used to displace an electron from the organic molecule to form a radical cation known as the molecular ion.
www.mhhe.com /physsci/chemistry/carey/student/olc/ch13ms.html   (607 words)

 Genesis : Search for Origins | JPL | NASA
Aston's mass spectrometer had a precision of one part in 10,000, which was sufficient for him to discover the isotopes of many elements.
If the beam of a mixture of particles of different masses is allowed to hit a photographic plate, the particles converge at different points, corresponding to the different radii of their semicircular paths.
Modern mass spectrometers feed their results directly to computers that do the analysis and produce a graph (spectrum).
www.genesismission.org /science/mod3_SunlightSolarHeat/MassSpectrometry/index.html   (613 words)

 Tandem Mass Spectrometry (MS/MS)
Tandem mass spectrometry (MS/MS) is perhaps the most significant advance in newborn screening in the past 30 years.
A tandem mass spectrometer is a specialized instrument that detects molecules by measuring their weight (mass).
Tandem mass spectrometry is also superior to other testing methods because the study of multiple chemicals at a time allows us to accurately pinpoint which specific disorder a child may have.
www.pediatrix.com /body_screening.cfm?id=343   (745 words)

 Tandem Mass Spectrometry
Mass spectrometers are used in many laboratories throughout the world to analyze thousands of compounds such as those present in our bodies, our environment, our medicines, manufactured materials, foods, poisons, and criminal evidence.
Tandem mass spectrometry requires several expert scientists to perform the analyses and medical experts to interpret the large amount of clinical data produced from the analysis of a blood sample.
Mass spectrometry is a tool that could expand the disorders screened for in qualified newborn screening laboratories having sufficient experience with the technology.
www.savebabies.org /NBS/msms-chace.php   (1691 words)

 Office of Research & Sponsored Programs
Mass of the unknown peptide/protein is deduced by averaging a requisite number of individual TOF measurements (20-1000, obtained by repeated laser firings at up to 20 times per second) and referenced to calibration standards of known mass.
Since mass spectrometers measure mass to charge ratio, not molecular mass per se, a pure protein gives multiple peaks on a quadrupole MS instrument, corresponding to one for each of its charge states.
A factor contributing to the precision of mass detection by ESI-MS/MS is that the mass of each of a proteins charge states contributes to the calculation of total mass.
www.med.cornell.edu /research/rea_sup/mass_spec.html   (1414 words)

 Ion Trap Mass Spectrometry
In this mode, analogous to the operation of a quadrupole mass filter, the amplitudes of rf and dc voltages applied to the ring electrode were ramped at a constant rf/dc ratio to allow stability, hence storage, of a single (increasing) m/z value in the ion trap.
Micro-electrospray ionization coupled to ion trap mass spectrometry was applied to the analysis of a peptide mixture resulting from the enzymatic digestion of recombinant tissue plasminogen activator (tPA), a mixture containing 51 expected tryptic peptides (7).
Unit mass resolution, or the ability to separate an m/z value of 1,500 from 1,501, is maintained over the 2,000 dalton mass range with a mass accuracy of 0.015%.
www.abrf.org /ABRFNews/1996/September1996/sep96iontrap.html   (4234 words)

 Mass Spectrometry   (Site not responding. Last check: )
Note that molecular weight, or more correctly formula weight (the mass in grams of one mole of compound), is actually a weighted average of the molecular masses of all the isotopic variants of a given molecule.
For small organic compounds a mass spectrometer can resolve the individual "isotopomers" and the mass of the major one (the so-called mono-isotopic mass) is very close to the formula weight of the compound.
All mass spectrometers consist of three basic components, a source for producing ions to analyze, a mass analyzer for separating ions according to their m/z ratios, and a detector for counting the ions (usually a simple photomultiplier tube connected to a computer).
www.brsl.ku.edu /bioms2.htm   (798 words)

 UNM Mass Spectrometry : MS Tutorial
Nominal Mass Determinations on Synthetic Molecules Above 150 Da This type of analysis is extremely useful for rapid monitoring of chemical syntheses where an average mass error of ± 0.2 amu (400 ppm or ± 0.04% for 500 Da) is sufficient to determine if the synthesis is indeed proceeding as planned.
The level of mass accuracy achieved with this approach would be useful for identifying proteins via peptide mass database searching where the higher mass accuracy will increase the specificity of the identification.
The only required input for Maximum Entropy processing is the expected molecular mass range of the compound of interest and an estimate of the peak width for a compound of that mass range with the number of charges needed to produce the observed multi-charged spectrum.
massspec.unm.edu /ms.htm   (1509 words)

 Mass Spectrometry Forum Column - Spectroscopy
The electron ionization (EI) source was the first source widely used for organic mass spectrometry (MS), and design, development, and optimization of this source are all the result of the work of many of the early pioneers of MS.
In addition to expressing his longing for a Star Trek "tricoder," columnist Ken Busch shows that the core processes of ionization, ion dissociation, and mass determination in mass spectrometry are all completed in very short times compared to the overall length of the analysis.
Part IV of this four-part series wraps up the discussion of mass calibration, covering the "new generation" attributes that have become apparent as researchers aim to meet the calibration demands of proteomics.
www.spectroscopymag.com /spectroscopy/article/articleList.jsp?categoryId=2322   (404 words)

 Mauritz - MALDI-TOF Mass Spectrometry
Due to the low molar mass of the polymer, the molar mass distribution is easily derived as 58 g/mol from the peak-to-peak mass increments.
At m/z 23000, the mass resolution is not sufficient to resolve adjacent oligomer molecular ions with a difference of 44 mass units.
This spectra has a continuous distribution due to convolution of the molecular ions, however, the molar mass for individual oligomers is apparent, as shown in the insert, with a peak-to-peak mass resolution of 104 g/mol.
www.psrc.usm.edu /mauritz/maldi.html   (2520 words)

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