
	Where results make sense

Topic: Mass spectrum

Related Topics

Mass spectrometry

In the News (Mon 28 Dec 09)

Northern Trust

Marvin Harrison

Peter Chernin

Gary Locke

Match Play

Penelope Cruz

Mickey Rourke

AR Rahman

Danny Boyle

Hugh Jackman

	Midland Certified--Mass Spectrum Interpretation
		A mass spectrum is a useful tool to aid in verifying that a synthetic oligonucleotide has the correct molecular weight.
		In calculating the mass of an oligo, remember that there are one fewer phosphates than nucleosides, and the value of 61.98 mass units must be subtracted.
		For reference, the mass of a typical 30-mer would be in the range of approximately 9,000 Daltons for which the expected error would be equivalent to the molecular weight of water, 18 Daltons.
	www.oligos.com /interpMassSpec.htm (503 words)

	Mass spectrum - Wikipedia, the free encyclopedia
		A mass spectrum is an intensity vs. m/z (mass-to-charge ratio) plot representing a chemical analysis.
		The x-axis of a mass spectrum represents a relationship between the mass of a given ion and the number of elemetary charges that it carries.
		The y-axis of a mass spectrum represents signal intensity of the ions.
	en.wikipedia.org /wiki/Mass_spectrum (1310 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 highest-mass ion in a spectrum is normally considered to be the molecular ion, and lower-mass ions are fragments from the molecular ion, assuming the sample is a single pure compound.
		The molecular ion in a mass spectrum is always a radical cation, but the fragment ions may either be even-electron cations or odd-electron radical cations, depending on the neutral fragment lost.
	www.cem.msu.edu /~reusch/VirtualText/Spectrpy/MassSpec/masspec1.htm (2839 words)

	MSMS Group @ USC Computational Biology (Site not responding. Last check: 2007-10-10)
		Mass spectrometry is a chemical analysis technique that is used to measure the mass of unknown molecules by ionizing, separating and detecting ions according to their mass-to-charge ratios.
		It is defined variously to be equal to the mass of the Hydrogen atom, 1/12 of the mass of the Carbon-12 isotope and 1/16 of the mass of the Oxygen atom.
		These ions are then passed to the mass analyzer where they are separated according to their mass-to-charge ratios and then go to the ion detector and their presence is recorded and the mass spectrum is produced.
	www-scf.usc.edu /~lijuanmo/msms/tutorial.html (3978 words)

	MALDI MS
		The maximum mass resolution observed in the linear mass spectrum of substance P employing continuous ion extraction is about 600 which is typical for a peptide of this size.
		A composite mass spectrum can be produced by combining the individual portions of the mass spectrum that were produced from the 10-20 different reflector potential steps that were required for observing the entire mass spectrum of fragment ions containing the desired sequence information.
		The obtainable mass resolution throughout the mass spectrum is also quite good (m/Dm typically ranges between 500 and 1000 for all ion signals observed) even though the DE instrumental parameters are typically optimized for the singly protonated pseudomolecular ion.
	www.abrf.org /ABRFNews/1997/June1997/jun97lennon.html (3622 words)

	Agilent \| MS Explained - Spectrum
		The lines in the mass spectrum represent the mass-to-charge ratio (m/z) of the molecular ion and the fragment ions.
		Mass spectral interpretation is the process of identifying a molecule by deducing information from its mass spectrum.
		The highest peak in the mass spectrum is the base peak and that is defined as 100 percent relative abundance.
	www.chem.agilent.com /Scripts/Generic.ASP?lPage=5484&indcol=N&prodcol=Y (598 words)

	UNM Mass Spectrometry : MS Tutorial
		Because mass spectrometers record mass-to-charge ratio, electrospray analyses on proteins typically produce a spectrum in the mass range of 500-2000.
		This spectrum containing multiply charged peaks is processed to produce a peak on a molecular mass scale by either transforming manually identified multiply charged peaks (adjacent peaks can only differ by one charge) or by MaxEnt transformation which only requires an accurate peak width as input.
		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)

	the mass spectra of elements
		The relative atomic mass of an element is the weighted average of the masses of the isotopes relative to 1/12 of the mass of a carbon-12 atom.
		10.8 is the relative atomic mass of boron.
		91.3 is the relative atomic mass of zirconium.
	www.chemguide.co.uk /analysis/masspec/elements.html (1035 words)

	GC Mass Spectroscopy
		In the bar graph form of a spectrum, the abscissa indicates the mass-charge (m/z) ration and the ordinate indicates the relative abundance.
		Mass separation is achieved by a combination of RF and DC fields with opposite polarities on the pairs of opposing rods.
		The mass of the molecular ion M+ is identical to the molecular weight of the compound from which it is generated.
	www-ec.njit.edu /~hsieh/ene669/gc_ms.html (1755 words)

	ms
		Different types of mass separators include magnetic sector (positively charged particles with the same energy and charge but different mass follow paths of different radii when they enter a magnetic field and therefore are separated according to mass), quadrapole and time of flight.
		As mass spectrometers separate isotopes, it is necessary to calculate molecular masses using the masses of the most common isotopes rather that the averages that appear in the periodic table.
		Thus the highest molecular mass peak in a spectrum may be from a isotopic molecular ion and not strictly definable as the molecular ion.
	virtual.yosemite.cc.ca.us /smurov/ms.htm (1534 words)

	Mass Spectrometry
		m are the masses of two particles that give just separable peaks (of approximately the same size) and the height of the valley between them is no more than 10% of their height.
		The mass spectrum usually consists of the molecular ion or parent peak and one or more fragments of the molecule.
		The peak at mass 18 is called the M peak while those at peaks 19 and 20 are called the M + 1 and M + 2 peak respectively.
	www.sonoma.edu /users/b/brooks/115b/massspec.html (531 words)

	Gas Chromatography Mass Spectrometry: Data Analysis
		This mass spectrum shows that a fraction of the chemical passed through the MS without breaking apart.
		If the mass spectra is not in the library, scientists can also use the fingerprint to work backwards to determine the original structure of the chemical.
		This is the mass spectrum of the pesticide DDT.
	www.unsolvedmysteries.oregonstate.edu /GCMS_06.shtml (318 words)

	EPA - Ion Composition Elucidation - Mass Peak Generation Model, EPA
		In Figure 3 are shown full and partial mass peak profiles plotted by connecting discrete points. Each point is the area of a chromatographic peak observed in the ion chromatogram acquired at the m/z ratio of the point.
		The theoretical exact masses and relative abundances of the composite +1 and +2 profiles are listed under the profiles in Figure 4a.
		In Figure 5, the m/z 415 ion was observed in the (a) raw and (b) background subtracted mass spectra.
	www.epa.gov /nerlesd1/chemistry/ice/spec.htm (1187 words)

	Chemistry 723--Separation Methods in Analytical Chemistry--GC/MS Laboratory
		The mass spectrum of a compound is often sufficient for chemical identification.
		In the mass spectrometer itself, ions are produced from the original molecules in an ion source, separated in the mass analyzer, and measured in the detector.
		The maximum mass range and resolution are determined by a variety of factors (geometry, ion source conditions, and rf parameters); mass ranges up to 1000 m/z and mass resolutions of 2000 are common in commercial quadrupole instruments.
	www.chem.sc.edu /analytical/chem723/gcmslab.html (2303 words)

	Evans Analytical Group LLC
		By plotting the abundance of ions as a function of mass-to-charge ratio, a mass spectrum is generated.
		With this technique, the most abundant (and characteristic) ion in the mass spectrum of each component to be quantitated is selected for scanning, and the instrument is programmed to scan this ion rather than the entire mass spectrum.
		Now, we have a mass spectrum of an ion, whereas in single-stage mass spectrometry we have a mass spectrum of a molecule.
	www.eaglabs.com /en-US/services/gcms.html (1240 words)

	MaxEnt Deconvolution
		Both the Sciex and the Micromass Maximum Entropy algorithms for deconvolution of electrospray mass spectrometry data answer the question: What is the most probable parent mass spectrum, given the data in front of me? Both use the same knowledge of the spectrometer: it creates multiple images and it smears the data.
		The data from a mass spectrometer produce an apparent mass spectrum y(m/z), where y is the number of counts at apparent mass m/z.
		The data y(m/z) are related to the parent mass spectrum o, and the noise n, by an equation that describes both the characteristics of the spectrometer and the statistics of the noise.
	www.spectrumsquare.com /maxent.htm (463 words)

	Mass spectrometry - Wikipedia, the free encyclopedia
		A mass spectrometer is a device that measures the mass-to-charge ratio of ions.
		A quadrupole mass analyzer acts as a mass selective filter and is closely related to the Quadrupole ion trap, particularly the linear quadrupole ion trap except that it operates without trapping the ions.
		The cylindrical ion trap mass spectrometer is a derivative of the quadrupole ion trap mass spectrometer.
	en.wikipedia.org /wiki/Mass_spectrometer (5079 words)

	Ionization Methods (Site not responding. Last check: 2007-10-10)
		Mass spectrometers measure the mass-to-charge (m/z) ratios of gas phase ions.
		A CI mass spectrum often contains a protonated molecule, [M+H]+, and a few fragment ions.
		An ESI mass spectrum usually consists of a series of multiply-charged ions, e.g.
	www.nd.edu /~massspec/ions.html (532 words)

	Mauritz - MALDI-TOF Mass Spectrometry
		The TOF mass spectrum is a recording of the detector signal as a function of time.
		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.
	www.psrc.usm.edu /mauritz/maldi.html (2520 words)

	MS Tools for the Mass Spec System User
		Mass Spec Tools is designed to be an information source for the mass spectrometer community.
		Just type in the mass spec peaks and their relative intensities and this program will generate a mass spectrum plot.
		The plot mass range can then be scaled to better view the relationship of the ions.
	www.sisweb.com /mstools.htm (321 words)

	NCRR Proteomics Resource at PNNL - Training: General Mass Spectra Tutorial (Site not responding. Last check: 2007-10-10)
		Structure of Parent: The total pattern of ions detected in a mass spectrum can reveal information about the composition and structure of the parent molecule.
		The mass spectrum of water would be similar to the spectrum above.
		Determine the exact mass of a peak to reveal its elemental composition.
	ncrr.pnl.gov /training/tutorials/mass_spec_tutorial.stm (260 words)

	Mass Spectrometry Unknown Data Sets
		This is a set of mass spectrometry data for the identification of unknown compounds.
		Mass spectra were aquired on the Widener University Finnigan 4000 quadrupole mass spectrometer with 70 eV electron ionization.
		Mass Spectra were saved as peak tables and formated as jcamp (*.jdx) files that may be viewed using a JCAMP viewer or using the CHIME plugin from MDLI.
	science.widener.edu /~svanbram/chem465/htmldocs/ms_unk.html (257 words)

	Mass Spectrometry (Site not responding. Last check: 2007-10-10)
		Mass Spectrometry is a very useful technique that is used for identification of compounds by their mass-to-charge ratios.
		Mass Spectrum is a plot of the m/z ratios of the ionic species present versus abundance.
		A quadrupole analyzer is a mass filter that creates a quadrupole field with a DC component and an RF component in such a manner as to allow transmission only of ions having a selected mass-to-charge ratio.
	ewr.cee.vt.edu /environmental/teach/smprimer/ms/ms.html (786 words)

	Frequently Asked Questions
		Chemical atomic masses are not correct to use for mass spectrometry of small molecules (under 2000 Da), in cases where you have at least unit mass resolution.
		For example, carbon has a chemical atomic mass of 12.0110, but the correct value to use for small molecule mass spectrometry would be the mass of carbon-12, which is 12.0000.
		As another example, the chemical atomic mass of chlorine is 35.4527, but the correct value to use for small molecule mass spectrometry is the mass of chlorine-35, which is 34.9688.
	www.umich.edu /~techserv/massspec/faq.htm (1063 words)

	The Dijet Mass Spectrum and a Search for Quark Compositeness at DØ
		A measurement of the dijet mass spectrum can be used to verify the predictions of quantum chromodynamics (QCD) for parton-parton scattering and to constrain the parton distribution functions (pdf) of the proton.
		The inclusive dijet mass spectrum (plot 1) is compared to a prediction made with the NLO parton event generator
		Plot 2: The correlations between the systematic errors in bins of the dijet mass spectrum (eps file).
	www-d0.fnal.gov /~d0qcd/dijet_mass (380 words)

	Mass Spectroscopy Tutorial
		In mass spectrometry, a substance is bombarded with an electron beam having sufficient energy to fragment the molecule.
		Since the bulk of the ions produced in the mass spectrometer carry a unit positive charge, the value m/e is equivalent to the molecular weight of the fragment.
		The spectrum displays a strong molecular ion at m/e = 92, small m+1 and m+2 peaks, a base peak at m/e = 91 and an assortment of minor peaks m/e = 65 and below.
	www.chem.uic.edu /web1/ocol/spec/MS1.htm (642 words)

	Solar Wind Mass Spectrum (Site not responding. Last check: 2007-10-10)
		Oxygen (mass 16) is actually the most abundant heavy element in the solar wind, and the true Iron (mass 56) abundance would be roughly 10% that of Oxygen.
		These include the element Nitrogen (mass 14), a Neon isotope (mass 22), the element Sodium (mass 23), the Magnesium isotopes (masses 25, 26), the element Aluminum (mass 27), the Sulfur element (mass 32), the Argon element (mass 36), and the Calcium element (mass 40).
		The Mass and MTOF sensors were designed and fabricated by the University of Maryland; their entrance deflection systems were built by the University of Bern.
	umtof.umd.edu /pub/full_spectrum.html (493 words)

Try your search on: Qwika (all wikis)