Organic salts

Chromatography Forum: LC Archives: Organic salts
Top of pagePrevious messageNext messageBottom of pageLink to this message  By Anonymous on Wednesday, January 1, 2003 - 07:49 am:

Can any body tell that some of organic salts analysis in HPLC the salt( Citrate etc... ) peak is not conisdered why?.


Top of pagePrevious messageNext messageBottom of pageLink to this message  By Anonymous on Monday, January 6, 2003 - 03:31 am:

What? Please reword your question so that it makes sense and, perhaps someone will reply.


Top of pagePrevious messageNext messageBottom of pageLink to this message  By Anonymous on Monday, January 6, 2003 - 06:30 am:

If I am correct, the question asked is: when we analyze aniline benzoate (chloride, acetate etc.), we usually check the aniline ion only. Where would we see in the chromatogram the anions like benzoate, chloride and acetate? Assuming that a phosphate buffer is used, those anions will be separated from the original cations.


Top of pagePrevious messageNext messageBottom of pageLink to this message  By C.Sychov on Wednesday, April 23, 2003 - 11:14 am:

The answer is obvious -- we`ll have two peaks :)
It`ll be in well-buffered eluent of course, under RP cond. , when using eluent with high water content. In NP mode the peak will be the only, but broad. It all depends on the speed of process of ion-pairing in system.
Constantine


Top of pagePrevious messageNext messageBottom of pageLink to this message  By jt on Friday, April 25, 2003 - 05:38 pm:

Assume the original question was about drugs developed in a salt form. Theoretically, we should have two peaks. However, in most cases, the anion is much smaller than the cation part and has little or no UV absorbance. so most analysis focus on the main component of the salt: the basic drug molecule. If the anion is the subject of interest, ion chromatographic methods are generally employed.


Top of pagePrevious messageNext messageBottom of pageLink to this message  By C.Sychev on Saturday, April 26, 2003 - 05:54 am:

Sure :)


Top of pagePrevious messageNext messageBottom of pageLink to this message  By Chris Pohl on Monday, April 28, 2003 - 12:35 pm:

If the question from anonymous the above was: why do we measure the concentration of the drug substance but not the counterion, that's a question that should be directed to industry regulators.

However, if the question is: why aren't both active ingredient and counterion detected in the same run, as mentioned above most counterions are not amenable to UV detection. Furthermore, addition of an ion pair reagent would be necessary in order to accomplish retention and typically addition of the ion pair reagent would eliminate (or at least significantly reduce) retention of the active ingredient since the ion pair reagent and the active ingredient would tend to have the same charge and electrostatic repulsion of the ion pair reagent would serve to minimize retention.


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