Analysis of basic compounds at high pH values by reversed-phase liquid chromatography.
Reversed phase high performance liquid chromatography (RPLC) is currently the method of choice for the analysis of basic compounds. However, with traditional silica materials, secondary interactions between the analyte and residual silanols produce peak tailing which can negatively affect resolution, sensitivity, and reproducibility. In order to reduce these secondary interactions, which comprise ion exchange, hydrogen bonding, and London forces interactions, chromatographic analyses can be carried out at low or high pH values where silanol groups and basic compounds are mostly uncharged. The chromatographic behaviour of a particular bidentate stationary phase, Zorbax Extend C18, was studied with a set of basic and neutral compounds. Thanks to a higher chemical stability than traditional silica based supports, analyses were carried out with a high pH mobile phase, which represents a good alternative to the acidic mobile phases generally used to reduce ion exchange interactions. The performance of this bidentate stationary phase was also compared with that of other supports and it was proved that it is advantageous to work with high pH mobile phases when analyzing basic compounds.
Stella
Cinzia
C
Laboratory of Pharmaceutical Analytical Chemistry - School of Pharmacy - University of Geneva, 1211 Geneva 4, Switzerland. Cinzia.Stella@pharm.unige.ch
Rudaz
Serge
S
Mottaz
Manuel
M
Carrupt
Pierre-Alain
PA
Veuthey
Jean-Luc
JL
D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D002853:Chromatography, Liquid / Q000379:methods*; D006863:Hydrogen-Ion Concentration; D007202:Indicators and Reagents
D007202:Indicators and Reagents