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I'm trying to derivatize a standard solution of acetic acid and ethylene glycol in acetonitrile (ACN). I'm taking 100 uL of the solution and 5 uL of BSTFA w 1%TCMS into a 20 mL headspace vial and heating at 80 C for 15 min before injecting. I ran a blank, 100 uL of ACN and 5 uL BSTFA w TCMS, and saw 3 large peaks in addition to the ACN peak. Here is the chromatogram.


Would you expect to see the 3 large peaks from the BTSFA w TCMS? I do not have any reference method or chromatogram to compare to and I haven't done this before. Just to make sure the peaks are not coming from the ACN, I injected just 100 uL of ACN. Here is that chromatogram. The 3 peaks are not preset.


Thanks for your replies,

Maybe mono and di tns of glycol? Try derivatising seperate. Do you have acces to gcms? Then you can identify
Entirely possible.

Peter Apps
The first chromatogram posted is of only 100 uL of ACN and 5 uL of BSTFA w 1% TCMS in a headspace vial. The vial did not contain any glycol or acetic acid. I am wondering if you normally see large peaks from the derivatizing agent?


Aldijkhuizen wrote:
Maybe mono and di tns of glycol? Try derivatising seperate. Do you have access to gcms? Then you can identify

We used BSTFA with TMCS (trimethylchlorosilane, not TCMS) a ton. But we always used DMF or pyridine as the solvents (and never did headspace). We ALWAYS got complete derivatization of ethylene glycol, propylene glycol, glycerin, etc.
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