Chapter 14 - Mass Spectrometry

methane

When ________ is blasted with high- energy electrons, for example, an electron is dislodged from the molecule, yielding a molecular ion with m /z 16.

Thomson

________ found that neon can be split into a more abundant isotope, 20Ne, and a less abundant isotope, 22Ne, when he recorded the first mass spectrum in 1911.

F W Aston

________ demonstrated, using improved instruments, that the majority of naturally occurring elements are isotope mixes.

volatile liquid

Gas and ________ samples can be put directly into the ionization chamber.

Mass spectrometry

________ did not become widely used until the 1950s, when commercial equipment with good resolution, dependability, and low maintenance costs were available.

Fast atom bombardment

________ (FAB) is one of the novel techniques that employs high- energy particles, such as xenon atoms accelerated to keV energies, to bombard a dispersion of a chemical in a nonvolatile matrix, creating ions of the compound and expelling them into the gas phase.

Positive ions

________ are accelerated into an analyzing chamber by a sequence of negatively charged accelerator plates inside a magnetic (electric in certain spectrometers) field perpendicular to the direction of the ion stream.

Mass spectrometry concepts

________ were first identified in 1898.

Volatile liquids

________ and even certain solids are vaporized because the inside of a mass spectrometer is maintained at a high vacuum.

Mass spectrometry

________ is an analytical technique for determining the mass- to- charge ratio (m /z) of ions, which were previously positive but are now both positive and negative.