Pressure decay test on MOSH/MOAH GC
If you suspect that the GC might have a leak, you can quickly check for a leak with the pressure decay test.
Your MOSH/MOAH GC system is not completely closed system. It has a few gas outlets which are equipped with PEEKsil® restriction capillaries.
Two restriction capillaries are installed at selector valve, and two restriction capillaries are installed at the back of EVE valves. See below pictures.
When you set a high column head pressure and stop the flow, the pressure will naturally drop because of those outlets and FID.
If there is significant leak on your GC system, the pressure drop will be faster than it should be. This guide will show you how to perform the pressure decay test and what is typical value when the system has no leak.
Before you start the pressure decay test, bubble tests on the four restriction capillaries are recommended.