Chromatography Forum

Ethylene glycol is analysing on GC-FID as it is not giving response in HS-GC.
I am using DB-1701 column which is used in USP monograph of Diethylene Glycol.

Recovery of ethlyne glycol is not reproducible in API.

I tried combination of DMSO and Amm.phosphate but API gets saturated if API concentration is increases.

Ethylene glycol is soluble in water and API is slightly soluble in water.

I want suitable diluent for ethylene glycol and API, want recovery of ethylene glycol in API.

what could be the reason? Can anybody suggest any diluent or any derivatisation reagent ???

Use DMF and trimethylsilyl derivatization (like BSTFA), easy. You need to run a DMF-derivatization agent blank, as ethylene glycol-2TMS will elute just after the derivatization agent (BSTFA), to make sure you're looking at EG-2TMS. You'll likely want to use a DB-1 or DB-5 type capillary, and run isothermal until after the EG-2TMS elutes (use like 60 to 80C column oven).

EG-2TMS will give a distinctive GCMS spectrum, more definitive than straight EG.