By kobykat on Wednesday, - 11:39 am:

O.k., trying to develop a good method for the seperation of pseudoephedrine in a matrix of other cold product ingredients (acetaminophen, etc). I've tried some different methods from various websites but I'm not obtaining any great results. Does anyone have some suggestions on a method, or how I can tweek the seperation via ion-pair, etc.? Thanks!

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By SIELC_Tech on Wednesday, July 7, 2004 - 01:59 pm:

Check this method it was developed for NyQuil/Advil type of formulations (pseudoephedrine, acetaminophen, doxylamine, dextromethorphan). Concentrations in the mixture match the real life sample (acetaminophen 500 mg other in 10-50 mg range. No ion-pairing reagent, base line separation short method run - 10 minutes. Check also a comparison with regular C18 method and you will see the difference. Problem is, that all compounds in the mixture are quite different in terms of hydrophobic properties, polarity and pKa (acetaminophen and pseudoephedrine vs. dextromethorphan) and on traditional columns achieving good separation with time efficient method is quite challenging:

http://allsep.com/makeCmp.php?cmp=Cmp_116

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By THP5 on Thursday, July 8, 2004 - 08:31 pm:

SILEC,

Do you have LC/MS compatible method with formic acid or ammonium formate? DO you make columns with 1 mm ID?