Home > Terms > English, UK (UE) > Quadrapole mass philtre
Quadrapole mass philtre
The instrumentation for mass spectroscopy that allows selection of ions of a specific m/e- ratio. As the desorbed material travels down an electric field toward the detector, it passes through a space boarded by four parallel rods, which are electrodes. All four electrodes have the same DC current, onto which is superimposed an AC current that oscillates at a rate calculated to retain within the four rods only ions of the desired m/e- ratio and to deflect all other ions. Thus, the signal-to-noise ratio is kept high. By varying the charges on the electrodes, the spectrum of ions can be sampled. An alternative design is the ion-trap, in which the desorbed ions enter a cavity bounded front and back by circular entrance and exit endcap electrodes, and on the sides by a ring electrode. The voltages on all three electrodes are varied so that in-coming ions, passing through aperture in the entrance endcap electrode are directed into a circular orbit inside the ring electrode, until a sufficient number are accumulated, at which time, they are directed through an aperture in the exit endcap electrode toward the detector in a sequence that reflects their m/e- ratio.
- Part of Speech: noun
- Synonym(s):
- Blossary:
- Industry/Domain: Biology
- Category: Biochemistry; Molecular biology
- Company:
- Product:
- Acronym-Abbreviation:
Other Languages:
Member comments
Terms in the News
Featured Terms
IPhone for Steve
Also called iPhone 4S, it's a special model officially released by Apple on the day before Steve Jobs died. The iPhone 4S is the first iPhone to ...
Contributor
Featured blossaries
Browers Terms By Category
- Cardboard boxes(1)
- Wrapping paper(1)
Paper packaging(2) Terms
- General jewelry(850)
- Style, cut & fit(291)
- Brands & labels(85)
- General fashion(45)
Fashion(1271) Terms
- Inorganic pigments(45)
- Inorganic salts(2)
- Phosphates(1)
- Oxides(1)
- Inorganic acids(1)
Inorganic chemicals(50) Terms
- General astrology(655)
- Zodiac(168)
- Natal astrology(27)