Chromatography Forum

Hello,

I am HPLC method development scientist, in one of pharmaceutical company.

During my HPLC method development, i am observed, some of the aldehydes and ketones give broad peaks.

If anybody faced same problem, in your experience, please share.

Regards
sreenivas

Are you derivatizing with DNPH?

What aldehydes and ketones? I do them on the GC.

Are you derivatizing with DNPH?

No, i did not derivatized with DNPH.
Iam injecting as such sample.

What aldehydes and ketones? I do them on the GC.

hello sir,

Please find the chemical name of which iam getting broad peak shape.

7-(3-(aminomethyl)-4-oxopyrrolidin-1-yl)-1-cyclopropyl-6-fluoro-4-oxo-1,4-dihydro-1,8-naphthyridine-3-carboxylic acid.

please find the chemical name which iam getting excellent peak shape in same HPLC method.
(Z)-7-(3-(aminomethyl)-4-(methoxyimino)pyrrolidin-1-yl)-1-cyclopropyl-6-fluoro-4-oxo-1,4-dihydro-1,8-naphthyridine-3-carboxylic acid.

what my question is both are almost same chemical structures, why this much difference observed in peak shape.

Please give help us.

Regards
sreenivas

It is really interesting to see such kind of difference between methoxyimino and ketone. The single thing that seems possible to me is; the interaction between ketone oxygen and hydrogen on the nitrogen (3-amino methyl group) which forms a conformationally stable six membered ring. This may be causing a partial positive charge to oxygen and may cause peak broadening???

It is really interesting to see such kind of difference between methoxyimino and ketone. The single thing that seems possible to me is; the interaction between ketone oxygen and hydrogen on the nitrogen (3-amino methyl group) which forms a conformationally stable six membered ring. This may be causing a partial positive charge to oxygen and may cause peak broadening???

hai,
Keto compound (Borad peak compund) peak shape is some waht better when kept the mobile phase pH around 7.0. But, at pH 7.0 my peak of interst (Prinicipal peak) is giving tailing peak.

If, you any idea to solve this problem.

Please help me.

regards
sreenivas

what are the chromatographic conditions? your molecule is possibly in zwitterion form at ph7

Why are you calling this molecules as ketones and aldehydes? Why not amines, or acids or zwitter-ions? At lower ph they are basic compounds, at pH 3-8 they are zwitter-ionic and at pH >8 they are acidic

Why are you calling this molecules as ketones and aldehydes? Why not amines, or acids or zwitter-ions? At lower ph they are basic compounds, at pH 3-8 they are zwitter-ionic and at pH >8 they are acidic

why because, i don't have problem with amines and acids.

When compound is converts to keto impurity, problem is observed.

It is not possible to share structures, why because formate is not supporting.
Please convert the given chemical name into structures. Then only you can undersatnd the problem easily.

I am working for Gemifloxacin mesylate-API.

Please check the structure in google, if possible.

Keto impurity: the difference b/w the gemifloxacin vs keto impurity is only in place of =N-OCH3 is replaces with =o (i am calling ketone).

Please check the gemifloxacin structure u can easily under stannd the problem.

1) What my question is, if it is zwitter ion why gemifloxacin give good peak shape at acidic pH ranges e.g 0.1% TFA as mobile phase.
2) When i inject same mobile phase keto impurity give very broad peak shape.
3) Why this much variation observed in peak shape, when gemifloxacin converts to keto impurity?


Please read thoroughly and if you have any idea share with us.


Regards
Sreenivas

Why are you calling this molecules as ketones and aldehydes? Why not amines, or acids or zwitter-ions? At lower ph they are basic compounds, at pH 3-8 they are zwitter-ionic and at pH >8 they are acidic

why because, i don't have problem with amines and acids.

When compound is converts to keto impurity, problem is observed.

It is not possible to share structures, why because formate is not supporting.
Please convert the given chemical name into structures. Then only you can undersatnd the problem easily.

I am working for Gemifloxacin mesylate-API.

Please check the structure in google, if possible.

Keto impurity: the difference b/w the gemifloxacin vs keto impurity is only in place of =N-OCH3 is replaces with =o (i am calling ketone).

Please check the gemifloxacin structure u can easily under stannd the problem.

1) What my question is, if it is zwitter ion why gemifloxacin give good peak shape at acidic pH ranges e.g 0.1% TFA as mobile phase.
2) When i inject same mobile phase keto impurity give very broad peak shape.
3) Why this much variation observed in peak shape, when gemifloxacin converts to keto impurity?


Please read thoroughly and if you have any idea share with us.


Regards
Sreenivas

Dear all,

I Think this is due to keto-enol tautomerism.

Please suggest how can develop reproducible method such type keto-enol tautomerism.

If it's really a case of tautomerism, increasing the temperature might help by speeding up the interconversion.

Usually, with a correct column and right pH you can solve this problem. If you want you can send me samples for free method development.