Chordoid glioma: a rare suprasellar mass.

Tandem Mass Spectrometry

A mass spectrometry technique using two (MS/MS) or more mass analyzers. With two in tandem, the precursor ions are mass-selected by a first mass analyzer, and focused into a collision region where they are then fragmented into product ions which are then characterized by a second mass analyzer. A variety of techniques are used to separate the compounds, ionize them, and introduce them to the first mass analyzer. For example, for in GC-MS/MS, GAS CHROMATOGRAPHY-MASS SPECTROMETRY is involved in separating relatively small compounds by GAS CHROMATOGRAPHY prior to injecting them into an ionization chamber for the mass selection.

Mass Spectrometry

An analytical method used in determining the identity of a chemical based on its mass using mass analyzers/mass spectrometers.

Glioma, Subependymal

Rare, slow-growing, benign intraventricular tumors, often asymptomatic and discovered incidentally. The tumors are classified histologically as ependymomas and demonstrate a proliferation of subependymal fibrillary astrocytes among the ependymal tumor cells. (From Clin Neurol Neurosurg 1997 Feb;99(1):17-22)

Spectrometry, Mass, Fast Atom Bombardment

A mass spectrometric technique that is used for the analysis of a wide range of biomolecules, such as glycoalkaloids, glycoproteins, polysaccharides, and peptides. Positive and negative fast atom bombardment spectra are recorded on a mass spectrometer fitted with an atom gun with xenon as the customary beam. The mass spectra obtained contain molecular weight recognition as well as sequence information.

Spectrometry, Mass, Secondary Ion

A mass-spectrometric technique that is used for microscopic chemical analysis. A beam of primary ions with an energy of 5-20 kiloelectronvolts (keV) bombards a small spot on the surface of the sample under ultra-high vacuum conditions. Positive and negative secondary ions sputtered from the surface are analyzed in a mass spectrometer in regards to their mass-to-charge ratio. Digital imaging can be generated from the secondary ion beams and their intensity can be measured. Ionic images can be correlated with images from light or other microscopy providing useful tools in the study of molecular and drug actions.