Relationship study between reversed phase HPLC retention and octanol/water partition among amphoteric compounds

K. Takács-Novák, G. Szász, Z. Budvari-Barany, M. Jozan, A. Lore

Research output: Contribution to journalArticle

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Abstract

The retention of eight non-congeneric amphoteric compounds was followed in a reversed phase (RP HPLC) system (C18/methanol-water vol. 50:50) in the pH range 4-9. The chromatographic behavior of the amphoterics is explained by means of their species distribution diagram (pH profile of the protonation macro- and microspecies) in the same pH interval. Maximum retention was observed at the isoelectric point of the compounds even in cases when the zwitterionic species was in a great excess over the neutral (uncharged) one. This finding reveals, that the retention at the isoelectric point (ie.p.) must be generated by the retention of the less polar, neutral form. The great similarity of pH dependent partition (octanol-water) and retention (C18/methanol-water) pattern provides further proof to the concept, that in cases of amphoteric compounds the neutral species is transferred into the octanol phase during octanol/water partition. Linear correlation analysis showed that logP(oct/w) and logk'(C18) are analogue lipophilicity parameters i.e.: the physico-chemical content of logk'(C18) corresponds to that of the octanol/water true partition coefficient.

Original languageEnglish
Pages (from-to)807-825
Number of pages19
JournalJournal of Liquid Chromatography
Volume18
Issue number4
Publication statusPublished - 1995

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Octanols
High Pressure Liquid Chromatography
Water
Isoelectric Point
Methanol
Protonation
Macros

ASJC Scopus subject areas

  • Molecular Medicine

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Relationship study between reversed phase HPLC retention and octanol/water partition among amphoteric compounds. / Takács-Novák, K.; Szász, G.; Budvari-Barany, Z.; Jozan, M.; Lore, A.

In: Journal of Liquid Chromatography, Vol. 18, No. 4, 1995, p. 807-825.

Research output: Contribution to journalArticle

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AU - Lore, A.

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