Institut de Chimie Moléculaire et des Matériaux d'Orsay

DSQ (Thermo Scientific. 2004)



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Build.: 410 groundfloor

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Source: Electron impact (EI) or chemical ionization (CI) with ammonia.

Analyser: Quadrupole

Mmasse range: m/z 30-1000

What you get: In electron impact are obtained M+ molecular ion and its fragments. In chemical ionization, one can get the pseudo molecular ion (MH+ or MNH4+).

Principle: The impact between the electron beam and molecules of the sample causes the ionization of the latter. M + e- --> M+. + 2e-. The instability of the ion M+. causes its fragmentation. The chemical ionization differs from the electron impact by adding an ionizable gas in the ionization chamber. M + NH4+. --> MH+ + NH3. and M + NH4+. --> (M + NH4)+

Options: Introduction of the sample by gas chromatography ( Thermo. Trace GC) or direct injection.