3
Vacuum System
API Source Interface
24 Orbitrap Fusion Series Hardware Manual Thermo Scientific
API Source Interface
The API source interface for the Orbitrap Fusion Series MS consists of the components of the
API source that are held under vacuum (except for the atmospheric pressure side of the ion
sweep cone) in a vacuum chamber that the forepump evacuates to a pressure of approximately
1.5 Torr for the Orbitrap Fusion MS and 2.7 Torr for the Orbitrap Fusion Lumos MS. The
API source interface includes an ion sweep cone, an ion transfer tube, two cartridge heaters, a
heater block, a sensor, a vent prevent ball, the RF lens, the exit lens, and lens L0 (Figure 10).
Figure 10. API source interface (Orbitrap Fusion MS cross section)
The ion sweep cone is a metal cone over the ion transfer tube. The ion sweep cone channels
the sweep gas toward the entrance of the ion transfer tube, acts as a physical barrier that
protects the entrance of the ion transfer tube, and increases source robustness. The net result
is a significant increase in the number of samples to analyze without a loss of signal intensity.
In addition, keeping the ion transfer tube entrance as clean as possible reduces the need for
frequent maintenance. Install the ion sweep cone to improve ruggedness when analyzing
complex matrices such as plasma or nonvolatile salt buffers. Remove the ion sweep cone
before performing NSI experiments.
The ion transfer tube is a metal, cylindrical tube that assists in desolvating ions produced by
the API spray insert while transferring them into the vacuum system.
The heater block contains two heater cartridges, surrounds the ion transfer tube, and heats the
tube to temperatures up to 400 °C (752 °F). A thermocouple measures the temperature of the
heater block. Typical temperatures of the ion transfer tube are 270 °C (518 °F) for H-ESI and
250 °C (482 °F) for APCI, but these temperatures vary with the flow rate and the mobile
phase composition. A decreasing pressure gradient draws ions into the ion transfer tube in the
Ion transfer tube (not shown)
RF lensVent prevent ball
Ion sweep cone
Heater block
Exit lens
Lens L0
Spray cone (directly
behind the sweep
cone)
Release latch
To Next Page
Loading...
