Hi what kind of solvent you are referring to ? You can refer to AOAC, USP etc as they will state assay methods for the chemicals. 

Hi,

determinating the purity may be harder than You think and boiling point will not give You any real data either, the easiest way is to look up the data sheet that comes with Your solvent when You buy it, in there You should find most of the impurities. This is one of the reasons people state the retailer of their chemicals in publications.

Furthermore even if You find a method for determinating the exact purity of the solvent it will differ not only between retailers but also batches of the same company, and this is the reason sometimes in publications You see that ''freshly distilled'' solvent was used etc.

If You are concerned about the purity of the solvent for Your reactions looking up the purification method for those solvents in ''Purification of Laboratory Chemicals'' will give You methods for purifying the solvents. These methods are designed for each solvent specially to remove the impurities, stabilizators most commonly present in the solvent of question.

What is the reason behind this purity check?

There unfortunately is not a simple 'one-stop-shop' solution for detecting low concentration impurities in commercial solvents. Organic impurities can be detected with NMR fairly easily-- I would recommend doing a large number of scans on the best instrument available to you.

A GC/MS may be able to reveal some things as well but it is difficult to ensure that the contaminants are from your sample and not residual analytes from previous uses of the column-- to avoid this you can run the column for an hour or so near max working-temperature to try to clear it out. You'll need to run the column at a low temperature to detect anything near the volatility of your own solvent.

Do you have any information about what the suspected  impurities might be? And what solvent are you working with specifically?