Residual Solvents: What ICH Q3C Means and Which Solvents to Avoid
Synthesis solvents not fully removed can end up in your research compound. Learn what ICH Q3C means, which solvents to watch for, and how to read solvent test results.
May 20, 2026 | 7 min read
Where Do Residual Solvents Come From?
Peptide synthesis involves multiple chemical steps, each requiring solvents to dissolve reagents, wash resins, and facilitate reactions. Common synthesis solvents include DMF (dimethylformamide), DCM (dichloromethane), acetonitrile, TFA (trifluoroacetic acid), and diethyl ether.
After synthesis, the peptide is purified (typically by HPLC) and then lyophilized (freeze-dried) to produce the final powder. Lyophilization removes most solvents, but trace amounts can remain trapped in the peptide matrix. These residual solvents are invisible, odorless at trace levels, and impossible to detect without analytical testing.