Enalapril mystery

Hi All!
Does anybody have an experience with Enalapril onto UPLC? I have a problem with it, because I detect it like a saddle when I try to transfer HPLC method to UPLC. (Just to remind, Enalapril peak is a pretty wide peak on HPLC, with Tailing about 1.6.)
I am assuming that I am dealing with diastereoisomers or something like that.
Please help!

Milosh

Answers

  • I think that you have problem with solution of the sample or to much stronger week needle wash. Try to solute the sample in a mobile phase similar to phase in the start of the gradient and prepare week needle wash similar to start of the gradient.

  • Hi Milosh,

    Would you be able to provide a bit of information regarding your method? Specifically, what column are you using (i.e, chemistry, dimensions, etc)? What is your mobile phase, pH, flow rate, and/or gradient conditions? What are you injecting (i.e., sample/standard matrix, analyte concentration) and what is your injection volume? Please post any information that you think might help.

    I did a quick search of the Waters website for enalapril and found this separation on a Symmetry C8 column: http://www.waters.com/webassets/cms/library/docs/symmetry80.pdf. How close/different are your conditions?

    Thanks,

    --Doug

  • Enalapril has two forms that interconvert slowly into each other. You will therefore get two peaks that elute close to each other, commonly with a step between the peaks, if you have achieved good resolution. The two forms are stereo-isomers around the nitrogen in the proline part of enalapril.

    You can get around this by increasing the temperature, which speeds up the interconversion, or by changing the pH.

    If you contact me at [email protected], I can give you more background information.

  • Thank you Uwe, I'll try to play a little with pH and temp... And I'll come back with results...

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