7
HTEC-500
6.
Online Elution Degassing System
The degassing component works to remove dissolved air from the mobile phase. The dissolved air
occasionally interferes with the HPLC pumping or electrochemical detection. To prevent unexpected
problems with the analyses, always use the degassing system. Mobile phase goes through the system
when the pump is running and it is automatically degassed. Please note that the degassing system does
not work to remove an air segment(s) from the inlet tubing.
The degassing component consists of a bunch of polymer capillary tubings located in a vacuum
chamber. The dissolved gases in the solvent are pulled through the tubing walls by the differential
pressure. To reduce the pressure in the chamber, a vacuum pump runs intermittently and a valve opens
and closes the connection between the low pressure chamber and the vacuum pump. This valve
generates a clicking noise.
Two Channels, 300
μ
l and 7.5 ml
Two channels (upper and lower) are installed in the online degassing system. Either the 300
μ
l channel or
the 7.5 ml channel can be used. The 300
μ
l channel is more efficient at exchanging the liquid in the
degassing component. At a flow rate of 500
μ
l/min of mobile phase, the degassing efficiency is the
same between the two channels. There is no independent switch to turn on and off the degassing
system. The main power switch regulates the power of the degassing system.
6-1.
If you think the degassing efficiency is reduced, you may diagnose the
problem by the following procedure:
• Replace the mobile phase at the end of the inlet tubing of the system with ultrapure water.
• Turn off the pump and use a syringe to aspirate 5 ml of mobile phase from the pump drain valve and
then close the valve. Leave the system off for 10 min. It is not necessary to remove the columns.
• Turn on the main power and listen to the degassing pump noise (not the HPLC pump). The pump is
supposed to stop in a few minutes. The pump has a function to create a vacuum chamber inside of
the degassing system to allow dissolved air to go through the tubing inside.
• If the degassing pump stops within 4.5 min, the degassing system is functional.
• If the pump works for 4.5 min continuously, the degassing system is likely to have a mechanical
problem. Please time precisely for 4 min. If the degassing pump runs for 5 min, the pump will stop
automatically to prevent overrunning regardless of whether the degassing component is working
properly or not.
