Inconsistent areas for gas injections.

[meenabk]

The areas for gas injections to Agilent GC with SCD is giving very inconsitent areas. It varies from 10,000 to 90,000 with each run. When liquid sample is injected the area difference is mostly within 1000. The injections are done at 40:1 split ratio.
What other information will be needed to suggest what the problem is?

thank you

[GasMan]

More information is needed.

Which Agilent model of GC.

Are you using a valve for gas injection

If you are using a valve, are you using pre-treated tubing and inlet such as Sulfinert, Silcosteel or Ultimetal treatments.

Gasman

[meenabk]

We are using Agilent Gc, 7890A model.
Yes there is a gas valve used, and all are pre treated.

[Johnny Rod]

What are the analytes? What solven are you using when you make a liquid injection? At what temperature is the gas valve kept?