Ethylene glycol in API

[swarup_80]

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 ???

[Consumer Products Guy]

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.