USP Glycerol monograph Related compounds analysis

[mennis]

Does anyone out there commonly run this test according to the USP. We are seeing an impurity peak in our sample chrom that is out of spec at around 0.3%. We even see this when we prepare a solution of USP Glycerin reference standard which leads me to believe its something system related. I was hoping someone out there might have some example chrom they can share.

[Consumer Products Guy]

Mennis - some samples of methanol contain an impurity which elutes at the ethylene glycol retention time; therefore it is recommended each lot of methanol be checked before using it to make up solutions and samples by injecting using the GC program to make sure it does not contain this impurity. We don't find interferences in either the references or our own glycerin samples.

Good news: I have example chromatograms
Bad news: I'd have to figure out how to upload them for viewing, I'm a Consumer Products Guy, not a Computer Guy.

I can try to do an upload tomorrow, but better would be if you can supply your E-mail address and I could E-mail to you in Microsoft Word.

[mennis]

CPG,
Thanks for the quick reply. My email is mike.ennis@qualitychemlabs.com. Unfortunately Im talking about the other GC test in the Glycerol monograph. It used to be called "Limit of diethylene glycol and related compounds" but was renamed "Related Compounds" the diluent in this test is water not methanol. Perhaps you run this test and have example chrom you can supply.

Thanks,
mennis

[Consumer Products Guy]

CPG,
Thanks for the quick reply. My email is mike.ennis@qualitychemlabs.com. Unfortunately Im talking about the other GC test in the Glycerol monograph. It used to be called "Limit of diethylene glycol and related compounds" but was renamed "Related Compounds" the diluent in this test is water not methanol. Perhaps you run this test and have example chrom you can supply.

Thanks,
mennis

Yeah, about 8 months ago I looked over the now-effective monograph tests, which I did put into simpler language for a facility (not saying that USP monographs are confusing or outdated, that would be an opinion). Yes, I have run this part of the test; the resolution sample and the glycerin sample are dissolved in water. The sample preparation and conditions for this part are actually carryovers from early glycerin monographs; USP has monkeyed with this a lot in the last few years, concerned about intentional DEG or EG adulteration. Since my chromatograms are in a Word document and not in jpg, I'm E-mailing the Word document to you, rather than trying to paste them into Paint and converting, then trying to upload somewhere. You may then upload them to this board if you like.

[tracyj]

I'm not having very good luck with the current USP method. I thought the dilution in just MeOH would be greatly improved over the MeOH/water in the previous method I'm not getting any resolution, only one big, ugly peak at 4.4 minutes.

I was hoping that I could also get a copy of the chromatograms that you have, whether they be from the old method, the new method, or both. My email address is tsalyard@vijon.com

thank you so much!!!!

[Consumer Products Guy]

I'm E-mailing both you and Mike (above posts) with recent and older chromatograms.