First of all, remember to perform the following good practices to prevent clogging of the needle at all times:
Replace the septa of the «Flushing» position after each batch of samples.
Soak the needle in some milli-Q water after each use in order to prevent potential damage at the needle due to long-term contact with the acid.
Clean potential acid drops on every septa after acid addition.
🤔 Problem
The needle shows no or smaller Helium flow, indicating that the needle may be clogged.
🌱 Solution
Check visually under a microscope for potential waste blocking the needle tip- and sideholes and carefully remove it.
If no waste is visible, try any of the following actions:
soak the needle in some milli-Q water and flush the needle with Helium to dry it. If the blocking persists, soaking in ethanol instead can be helpful, though extra thorough drying should be then performed
try to carefully clean the two holes in the double-walled headspace needle with a thin wire
flush the needle under higher pressure (eg. 3 mbar) in order to remove potential remnants of septa or other waste inside the needle
switch the capillaries, connecting the sample-out capillary to the sample-in at the back of the CHS2 to flush out particles from the side hole, applying either normal or higher (eg. 3 mbar) pressure
bend the tip of the needle over the capillary (it should be done at Ionplus)
If none of the aforementioned actions help, swapping-out the needle might be probably the most reasonable solution!