Ch 9b

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Ch 9b
2013-01-12 14:06:58
Mass Spectrometry

Ch 9b
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  1. A technique, useful in structure elucidation, that is based on generating ions of a molecule in a magnetic field, then instrumentally determining the mass to charge ratio, and relative amounts of the ions that result.
    Mass spectrometry
  2. The mass to charge ratio of the ions detected by mass spectrometry, where m is mass and z is charge.
    m/z ratio
  3. The most intense peak detected in mass spectrometry.
    Base peak
  4.  The conversion of molecules to ions
  5. An ionization method in mass spectrometry that places a sample under high vacuum then bombards it with a beam of high-energy electrons, which dislodges a valence electron from the gas-phase molecules and produces molecular ions that have a +1 charge and an unshared electron.
    Electron impact ionization
  6. The radical cation that has a +1 charge and an unshared electron, M∙+, which is produced in a mass spectrometer when one electron is dislodged from the parent molecule.
    Molecular ion
  7. Ions produced by dissociation of the molecular ion in mass spectrometry
    Fragmentation pattern
  8.  A rule that states that if the mass of the molecular ion in a mass spectrum is an even number, the parent compound contains an even number of nitrogen atoms (zero is an even number).
    Nitrogen rule
  9. An ionization method in mass spectrometry in which a solution of the analyte is sprayed into the vacuum chamber of the MS from the tip of a high-voltage needle, and the extreme electrical potential imparts multiple charges to the analyte, and thus a family of m/z peaks
    Electrospray ionization (ESI)
  10. The method used in mass spectrometry to separate the ions of the sample that have been formed prior to detection.
    Ion sorting
  11. A technique in which an analyte is mixed with low molecular weight organic molecules that are known for their ability to absorb and transfer energy from the laser to the analyte in the mass spectrometer
    Matrix-assisted laser desorption ionization (MALDI)
  12. A technique that couples gas chromatography (GC) with mass spectrometry (MS); the GC separates components of a mixture, then the MS gives the molecular weight and structural information about each component
    GC/ MS analysis