Войдите в систему

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 tend to adsorb strongly on polar surfaces, influencing their separation.

Several factors affect the distribution of the analyte, including column temperature and the characteristics of the stationary and mobile phases. The distribution constant for a given analyte is a key concept that expresses the ratio of the amount of the analyte adsorbed on or dissolved in the stationary phase to the amount of the analyte present in the mobile phase at a specific moment during the separation.

Commonly polar stationary phases, such as silica and alumina, are widely used in packed-column and planar chromatography. The solute's polarity determines the type of stationary phase and solvent. For example, highly active adsorbents may be utilized for weakly polar solutes, while more polar solvents can effectively carry polar compounds. The ability of the solvent to transport the analyte depends on its overall polarity, the nature of the solute, and the polarity of the stationary phase.

Из главы 11:

article

Now Playing

11.3 : Analyte Adsorption and Distribution

Principles of Chromatography

419 Просмотры

article

11.1 : Chromatographic Methods: Terminology

Principles of Chromatography

582 Просмотры

article

11.2 : Chromatographic Methods: Classification

Principles of Chromatography

679 Просмотры

article

11.4 : Diffusion on Chromatography Columns

Principles of Chromatography

318 Просмотры

article

11.5 : Chromatographic Resolution

Principles of Chromatography

252 Просмотры

article

11.6 : Column Efficiency: Plate Theory

Principles of Chromatography

351 Просмотры

article

11.7 : Column Efficiency: Rate Theory

Principles of Chromatography

194 Просмотры

article

11.8 : Optimizing Chromatographic Separations

Principles of Chromatography

265 Просмотры

article

11.9 : Silica Gel Column Chromatography: Overview

Principles of Chromatography

750 Просмотры

article

11.10 : Thin-Layer Chromatography (TLC): Overview

Principles of Chromatography

788 Просмотры

article

11.11 : Gas Chromatography: Introduction

Principles of Chromatography

455 Просмотры

article

11.12 : Gas Chromatography: Types of Columns and Stationary Phases

Principles of Chromatography

343 Просмотры

article

11.13 : Gas Chromatography: Sample Injection Systems

Principles of Chromatography

278 Просмотры

article

11.14 : Gas Chromatography: Overview of Detectors

Principles of Chromatography

277 Просмотры

article

11.15 : Gas Chromatography: Types of Detectors-I

Principles of Chromatography

262 Просмотры

See More

JoVE Logo

Исследования

Образование

О JoVE

Авторские права © 2025 MyJoVE Corporation. Все права защищены