Capillary electrophoresis (CE) is a powerful analytical technique used to separa

Capillary electrophoresis (CE) is a powerful analytical technique used to separate and analyze charged molecules based on their size and charge-to-mass ratio. It relies on the principles of electrophoresis, which is the movement of charged particles under the influence of an electric field.
Here are some key points regarding capillary electrophoresis:
1. Principle: Capillary electrophoresis takes advantage of the differential migration of charged analytes in an electric field. The separation occurs in a narrow capillary filled with an electrolyte solution. When an electric field is applied, positively charged analytes (cations) migrate toward the cathode, while negatively charged analytes (anions) migrate toward the anode. The separation is based on differences in their electrophoretic mobility, which is influenced by size, charge, and shape.
2. Capillary: CE utilizes a small-diameter capillary (typically 25-100 μm in internal diameter) as the separation column. The capillary is typically made of fused silica, a chemically inert material that minimizes sample adsorption and interactions.
3. Sample injection: Sample introduction into the capillary can be achieved by different techniques, including hydrodynamic injection, electrokinetic injection, or pressure-assisted injection. Each method has its advantages and is selected based on the specific requirements of the analysis.
4. Types of CE: There are several variants of capillary electrophoresis, including capillary zone electrophoresis (CZE), capillary isoelectric focusing (CIEF), micellar electrokinetic chromatography (MEKC), and capillary electrochromatography (CEC). Each variant employs different mechanisms to achieve separation and is suitable for different types of analytes.
5. Detection: CE can be coupled with various detection methods, such as UV-vis absorption, fluorescence, mass spectrometry (MS), or electrochemical detection. The choice of detection method depends on the nature of the analyte and the sensitivity required.
6. Applications: Capillary electrophoresis has found applications in various fields, including pharmaceutical analysis, environmental monitoring, forensic sciences, proteomics, genomics, and food analysis. It is particularly useful for the analysis of small molecules, peptides, proteins, nucleic acids, and chiral compounds.
7. Advantages: CE offers several advantages over traditional separation techniques such as high separation efficiency, short analysis time, small sample and reagent consumption, and compatibility with a wide range of analyte types. It is also amenable to automation and high-throughput screening.
8. Limitations: Despite its advantages, capillary electrophoresis has some limitations. It is primarily suitable for the analysis of charged analytes, and neutral compounds need derivatization or complexation for analysis. It may also suffer from poor reproducibility due to the sensitivity of the separation to various parameters such as temperature, pH, and capillary surface properties.
9. Advances: Ongoing research in capillary electrophoresis focuses on the development of new separation techniques, improved detection methods, and the integration of CE with other analytical techniques for multidimensional analysis.
Capillary electrophoresis is a versatile technique with broad applications in analytical chemistry and life sciences. Its ability to separate charged molecules with high resolution and efficiency makes it a valuable tool for many scientific and industrial applications.