After a solvent evaporates off of a surface there's always some residue left in the form of a strain.
Why it is the case even for highly volatile solvents such as acetone, toluene etc?
Chemistry Stack Exchange is a question and answer site for scientists, academics, teachers, and students in the field of chemistry. It only takes a minute to sign up.Sign up to join this community
If the surface material is clean and neither soluble nor reactant in any way with the solvent, then it is probably a solvent purity issue. If you have a good micro-balance, you could pour a known volume of the solvent into a pre-weighed light-weight, i.e. aluminum foil, container, dry it, and re-weigh. From that you can calculate the non-volatile solids content of your solvent and compare it to the specifications.
The most common reason why evaporating solvents leave a residue is because they are good solvents and some of the surface or contaminants on the surface are dissolved in the solvent. This is very common for most non-inert surfaces with solvents like acetone.
Another explanation when the surface is very unreactive (glass for example) is that the evaporation of a volatile solvent cools the surface and causes other things (like water vapour) to condense onto the surface. This is certainly true for dichloromethane and ether which are so volatile that evaporating a large amount can freeze nearby water.