​Regulatory Driver: USP monographs, IP, and regulatory alerts require gas chromatography (GC-FID) limit tests for EG and DEG before release.
- ​Analytical Method: A capillary GC-FID method using a cyanopropylphenyl/dimethylpolysiloxane or polyethylene glycol phase column.
- ​Acceptance Limits: Both Ethylene Glycol and Diethylene Glycol must each be not more than 0.10% (w/w) [1000 ppm]. General wet-chemical identification or simple specific gravity/refractive index tests are compendially insufficient to release these excipients.