analysis ethylene glycol monoethyl ether in API

[zhengmin]

Hello,everyone:
I will determine ethylene glycol monoethyl ether which is a residue solvent in API, and I analysis it with HP-5, injection temperature is 150 degree. when I dissolve the API sample in water, the peak of ethylene glycol monoethyl ether is splited, Howerer, when I dissolve the API in DMSO, the peak is not splited,but the response is very low. (the RT is about 7 min), the graph of the peak is fat. can you tell me what is wrong with me? how can I do? any suggestion is appreciated. thanks

[chromatographer1]

I would suggest you change your dissolution solvent. It may be reactions consume your analyte in the injector port when certain solvents are used. I would recommend methanol or IPA as a dissolution solvent (blindly, not knowing your API). Headspace analysis would fix your problem, most likely.

Good luck and let us know how things turn out.