Related Experiment Video
Updated: Jul 29, 2026
13:35
A Convenient Method for Extraction and Analysis with High-Pressure Liquid Chromatography of Catecholamine Neurotransmitters and Their Metabolites
Published on: March 1, 2018
Retention processes on alpha 1-acid glycoprotein-bonded stationary phase
E Arvidsson1, S O Jansson, G Schill
1Analytical Chemistry, Astra Hässle AB, Mölndal, Sweden.
Journal of Chromatography
|February 7, 1992
Summary
Separating charged enantiomers using chiral chromatography (CHIRAL-AGP) is controllable by adjusting mobile phase pH and additives. This study reveals stereoselectivity arises from combined ion-exchange and ion-pairing mechanisms with alpha 1-acid glycoprotein.
Area of Science:
- Analytical Chemistry
- Chromatography
- Chiral Separations
Background:
- Chiral separations are crucial for pharmaceuticals and biochemicals.
- Alpha 1-acid glycoprotein (AGP) is a common chiral stationary phase for enantiomer resolution.
- Controlling stereoselective separations on AGP requires understanding mobile phase interactions.
Purpose of the Study:
- To investigate the mechanisms governing stereoselective separations of charged enantiomers on CHIRAL-AGP.
- To elucidate the role of mobile phase composition, specifically pH and additives, in controlling enantiomeric retention.
- To optimize separation conditions for improved stereoselectivity.
Main Methods:
- Utilized CHIRAL-AGP chromatography for enantiomer separation.
- Varied mobile phase pH and introduced charged/uncharged additives.
- Monitored retention times and employed indirect detection.
- Applied multivariate design to analyze variable effects.
Main Results:
- Stereoselective separation of charged enantiomers on CHIRAL-AGP is effectively controlled by mobile phase pH and additives.
- Retention and stereoselectivity are influenced by simultaneous ion-exchange and ion-pairing interactions with alpha 1-acid glycoprotein.
- Anionic and cationic additives (chiral or achiral) significantly improved stereoselectivity through synergistic or competitive effects.
Conclusions:
- The stereoselectivity in CHIRAL-AGP separations is a result of combined retention mechanisms.
- Mobile phase manipulation, particularly pH and additive selection, offers a powerful strategy for optimizing chiral separations.
- Understanding these interactions allows for targeted improvements in enantiomeric resolution for charged compounds.
Related Concept Videos
01:10Silica Gel Column Chromatography: Overview
Silica gel column chromatography is a technique for separating compounds using a column packed with silica gel as the stationary phase. This method relies on differences in the polarity of compounds. Based on their polarities, compounds move between the stationary phase (silica gel) and the mobile phase (the solvent), forming discrete bands in the column.
Polar components tend to bind strongly to the silica gel, causing them to move slowly through the column. In contrast, nonpolar compounds...
Polar components tend to bind strongly to the silica gel, causing them to move slowly through the column. In contrast, nonpolar compounds...
01:09Analyte Adsorption and Distribution
In certain chromatographic separations, solutes transfer between the mobile phase and the stationary phase via sorption, which typically refers to the process of adsorption. For many chromatographic systems, the sorption process often depends on the polarity of the compounds—an expression of the overall dipole moment within the molecule. During the separation process, there is competition between the solute and solvent for adsorption to the stationary phase. Highly polar compounds and solvents...
01:17Gas Chromatography: Types of Columns and Stationary Phases
Gas chromatography (GC) relies on stationary phases to separate and analyze components in a sample. There are two main types of stationary phases: liquid and solid. Liquid stationary phases are non-volatile, thermally stable, and chemically inert liquids coated onto the column. Solid stationary phases are particles of adsorbent material, such as silica gel or molecular sieves.
For an analyte to remain on the column for a sufficient amount of time, it must exhibit some level of compatibility (or...
For an analyte to remain on the column for a sufficient amount of time, it must exhibit some level of compatibility (or...
01:11High-Performance Liquid Chromatography: Introduction
High-performance liquid chromatography(HPLC), formerly referred to as High-pressure liquid chromatography, is a powerful technique used to separate, identify, and quantify components in complex mixtures. The term "high pressure" refers to using high pressure to push the liquid mobile phase through the tightly packed columns.
In HPLC, two phases play a critical role in the separation process:
In HPLC, two phases play a critical role in the separation process:
01:09Ion-Exchange Chromatography
Ion-exchange chromatography, or IEC, is a technique for separating ions based on their affinity for the stationary phase. The stationary phase is a cross-linked polymer resin with covalently attached ionic functional groups. The functional groups can be either positively charged (cation exchangers) or negatively charged (anion exchangers). A cation exchanger consists of a polymeric anion and active cations, while an anion exchanger is a polymeric cation with active anions. The choice of...
01:03Affinity Chromatography
Affinity chromatography is a powerful technique extensively utilized for separating and purifying specific biomolecules from complex mixtures. It capitalizes on the highly selective binding between an analyte and its counterpart, such as antibody-antigen interactions. The counterpart is immobilized on the stationary phase, forming an affinity column. The stationary phase typically consists of solid support, such as agarose or porous glass beads, immobilizing the affinity ligand. The mobile...