Chromatography Forum

I am running an organic standard sample in a reverse phase HPLC system (LCMStrap). The fragments appearing in my mass spec are as expected, but I'm getting two or three peaks on my LC chromatogram for every standard, which should be pure? The peaks are not typical "split peaks", they are eluting at least 3 minutes away from each other. Do you think it is possible that my sample is decomposing in or before the column? Does anyone have any other suggestions as to what might be happening? My compound is 1,2,4-Triacetoxybenzene dissolved in 50/50 methanol/water (which should be stable...) and my method employs a linear gradient technique with methanol and water mobile phase.

some additional info:
-flow rate: 1ml/min
-injection volume: 20 microL
-sample concentration: 1mg/mL
-column: -SUPELCOSIL LC-18 HPLC column and SUPELCOSIL LC-18 Supelguard Cartridge

Any insight/suggestions would be much appreciated!

Are you seeing the peaks in your blanks? If it isn't something from your neat solution or matrix, then a very simple way of looking at this would be that your compound can have many ionic/chemical forms in solution (looking at your compound, I'd say so), and they could retain very differently on a column.

You can easily eliminate this with some pH/buffer control in your mobile phases (and/or the 1:1 meoh:water)