The heater block on the API source interface contains two heater cartridges that surround the ion transfer tube and heat 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 atmospheric pressure region and transports them to the API source interface region of the vacuum manifold.
| No. | Description | No. | Description |
|---|---|---|---|
1 | Heater block | 2 | Heater cartridges |