Chromatography Forum

Greeting.

I am doing a new research in glycerine. The interest is to identify the traces of organic compounds in an almost pure glycerine (99.5%). I am given an Agilent GC-FID and GC-MS to work with.

For a start, I have prepare a 10% v/v glycerine in ethanol and injected into GC-FID with DB-wax column 0.25 mmid, 0.25 micron 30 metre. Inj temp 280C, detector 280C, oven 100c (4min), ramping at 7.5 c/min to 250c. The peak separation was not good, the shape of glycerine was not symmetrical.

Are there anyone out here that have previous experience on similar project? I would appreciate some advice or reference. Thanks.

Lee

Start with a set up like the USP glycerin section for the GC assay of glycerin for diethylene glycol and related materials on a polar capillary; this assay just uses the glycerin sample dissolved in water. Glycerin may also contain trace amounts of fatty acids; for these we dissolve the sample in DMF, make trimethylsilyl derivatives, and use a nonpolar capillary. Since you say you're dealing with 99.5% glycerin, it's doubtful you'd have any significant levels of mono-, di-, or triglycerides. Also (and strangely), 99.5% glycerine USP can actually contain up to 5% water, and still be labeled 99.5% glycerin, if I read the USP definition correctly.