ALS Settings - How to reduce air gap after sample during syringe cleaning?

In the Washes and Pumps section, look at the column labeled Volume.  This indicates the volume used to wash the syringe.  When set to Max, it will use 80% of the syringe volume (8 uL in your case because the syringe is 10 uL).  Sample wash volume is set to 2 uL.  That is why the syringe pulls up 2 uL of sample and then 6 uL of air.

Thank you for your answer.

I noticed, afterwards, that there is a help button on that page and it explained what you said.

So, whatever the volume selected for wash (solvents A/B and sample), the rest of the volume will be air to complete the 80% of the syringe volume.

I wish it was not the case because my sample is moisture sensitive and I don't need it all over the syringe when I only need 1µL for injection. 

After several injections done and system in standby, the syringe gets stuck because of the reaction between leftover sample and atmospheric moisture.

Thank you for your answer.

I noticed, afterwards, that there is a help button on that page and it explained what you said.

So, whatever the volume selected for wash (solvents A/B and sample), the rest of the volume will be air to complete the 80% of the syringe volume.

I wish it was not the case because my sample is moisture sensitive and I don't need it all over the syringe when I only need 1µL for injection. 

After several injections done and system in standby, the syringe gets stuck because of the reaction between leftover sample and atmospheric moisture.

it's really good knowledge point