LC-MS contamination - (Oct/17/2005 )

We just got a Q-star system from Applied Biosystems. We want to run nano LC-MS/MS analysis to identify some proteins digested from 2D gels! But we have a lot of contaminants and we have not ideas about the origin... (we use solvents LC-MS grade). Does someone know contaminant lists or databases of contaminants so we can identify this substances?
Any other piece of advice is wellcome.
Please give me some suggestion..
Thank you very much.

keratin and others skin hairs components are standard contaminants in MS...
that's just a general info, sory about that point, but i'm not in touch wih LCMS or MS...
fred

Thanks Fred, but we check for keratin (human, sheep, and other)... we suspect some chemical contaminants from the nano LC or from the vials. Without any database information is very hard to understand the origin of contaminat...
Thanks anyway
Bye
Francesco

What are you using to prep your samples? Perhaps some fault lies there....

Just an idea..