Chromatography Forum

Hi,

We recently ran a synthesized peptide on a column for a standard curve and found a pretty unusual peak shape. It looks like peak tailing but we wonder if it might be an impurity from the synthesis. In the image below, the top chromatogram is a sample and the bottom is the standard. We don't believe we are overloading the column as we are well within the column's capacity. Has anyone else observed this and if so, did they find this was a result of an isomer in the synthesis or just a result of peak tailing based on concentration and matrix?

Your peak shape does not look like the type of tailing I am used to seeing.

I would guess you are seeing something(s) co-elute with your analyte, or your column may have a problem.

Have you tried an injection on a new or different (but same type) column??

Is your analyte being retained on the column to a sufficient degree to remove it from the void volume (does a non-retained compound elute well before the analyte)?

Can you alter your chromatographic conditions in order to try to separate your analyte from anything else that may be co-eluting (assuming your column is still good).

It may also be possible that your sample is not being introduced into your detector properly. I assume you are using LCMS, some sort of ionspray? Is the ionspray working efficiently?

i am also observing a similar type of peak tailing in my LCMSMS when i run pesticide using a atlantis T3.when i wash the column with acetonitrile and water in different combination ranging from 10% to 90% by reversly.After that the peak shape is OK.I think it is because of the column,try a different column or similar column or wash the column properly.