Organic modifiers for the separation of organic acids and bases by liquid chromatography.
A straight-chain alcohol or diol additive in the mobile phase was used to modify and improve the HPLC separation of organic acids and bases. Incorporation of 2% 1-butanol, 1% 1,2-hexanediol, or 0.25% 1,2-octanediol into an aqueous mobile phase greatly improved the separation of alkane carboxylic acids on a silica C18 column, both in terms of separation time and peak shape. When 1.5% 1-hexanol, 0.09% 1-decanol or 0.01% 1-dodecanol was added to an acetonitrile-water (30:70) mobile phase, much sharper peaks and better resolution were obtained for aromatic bases separated on an underivatized polystyrene-divinylbenzene column. The mobile phase additive is believed to coat the stationary phase surface by a dynamic equilibrium. The coated surface is more hydrophilic and facilitates the efficient partitioning of analytes between the mobile and stationary phases.
Li
Shelly
S
Ames Laboratory, US Department of Energy and Department of Chemistry, 322 Wilhelm Hall, Iowa State University, Ames, IA 50011, USA.
Fritz
James S
JS
D000143:Acids / Q000302:isolation & purification*; D000468:Alkalies / Q000302:isolation & purification*; D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D009930:Organic Chemicals / Q000737:chemistry*; D013056:Spectrophotometry, Ultraviolet
D000143:Acids; D000468:Alkalies; D009930:Organic Chemicals