Bubble test on restriction capillaries
On GERSTEL MOSH/MOAH System, there are four PEEKsil® restriction capillaries installed. Two capillaries are installed on the Selector Valve, and the other two are installed on the back of the EVE.
The ends of these capillaries that are not connected are open. When there is a carrier gas flow on the GC, the capillaries also have a flow during ready and standby status and most time of the run.
These capillaries should not be blocked. A typical symptom of the blockage is random noise on the baseline, as shown below:
To check if those capillaries are blocked, you can perform a bubble test.