Chromatography Forum

Hi all,

I'm running a GC system testing: Methanol, dichloromethane, o-xylene, ethyl acetate and acetone.
I'm currently validating the method and the %RSD for all solvents was allways not more then 2.0%
In the last sequence there was a strange problem were the %RSD for only methanol and o-xylene was very high (about 16%)
What could cause repeatability issue for only these solvents?

I'm using a headspace sampler with a gas tight syringe
Column: DB-624 30m x 0.32mm x 1.8um

Anyone?

I don't see a pattern with regard to MW or volatility - it might give others some ideas if a matrix was provided - what is the matrix that is being tested for with regard to these chemicals?

We need to know a lot more about what you are doing and how you are doing it. The nore you don't tell us the more we can't help you.

Peter