Microcolumn liquid chromatography with sample induced internal pH gradient

Abstract

Abstract. An internal pH gradient of a wide range of pH can be developed using the pumped mobile phase containing only a few [3][4][5][6] simple buffering salts which differ in pka values by about 1 pk, unit or less. The use of several types of surface ionizable groups allows the internal pH gradient to be effective not only for separation of ampholytes but also for separation of anions of both strong and weak acids. The internal pH gradient can be induced simultaneously with solute introduction into the separation column. For this new method, the term "sample induced internal gradient" (SIIG) of pH was suggested. The method is demonstrated by separation of model mixtures of UV detectable anions and ampholytes on a dynamically modified microcolumn.

Single‐Component Eluents for Quasi‐Linear pH Gradients in Weak Cation Exchange Columns

“…The few attempts using a 3 -5 component buffer eluent for generation of pH gradients in anion-exchange column are published. [5,8,9] Recently, a single-component eluent was used for production of a linear or quasi-linear pH gradient in an anion-exchange column and applied to separation of model mixture of amino acids. [10,11] The term "quasi-linear gradient."…”