Figure 11. Ltq Xl Ion Source Interface (Cross Section) - Thermo Scientific LTQ Series Hardware Manual

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Figure 11. LTQ XL ion source interface (cross section)

Ion sweep
cone
Spray cone
(immediately behind
the sweep cone)
Ions from the tube lens pass through the skimmer and move toward the MP00
skimmer acts as a vacuum baffle between the higher pressure ion source interface region and
the lower pressure MP00 rf lens region of the vacuum manifold.
For the LXQ and LTQ XL, ions from the ion transfer tube enter the tube lens
The API tube lens offset voltage
background gas that is present in the ion transfer tube–skimmer region. Collisions with the
background gas aid in the desolvation of the ions and increase sensitivity. However, if the tube
lens offset voltage is too high, collisions with the background gas can be energetic enough to
cause ion fragmentation. This fragmentation, or
ion transfer tube–skimmer region decreases sensitivity. Therefore, when you tune the LXQ or
LTQ XL mass spectrometer, adjust the tube lens offset voltage to maximize sensitivity by
balancing desolvation with fragmentation.
Vent prevent ball
Ion transfer tube
Heater block
applied to the tube lens accelerates the ions into the
collision-induced dissociation
2
Functional Description
Mass Spectrometer
Tube lens
Skimmer
rf lens. The
(Figure 12).
(CID), in the
LTQ Series Hardware Manual 17