Capillary electrophoresis–mass spectrometry

Schematic Diagram of CE-ESI-MS system

Sheathless Interface

Sheath Flow Interface.jpg

Schematic Diagram of CE-MALDI-MS

Capillary electrophoresis–mass spectrometry (CE-MS) is an analytical technique that combines the separation capabilities of capillary electrophoresis (CE) with the detection capabilities of mass spectrometry (MS). This technique is widely used in the fields of biochemistry, pharmaceutical sciences, and clinical diagnostics for the analysis of complex biological samples.

Principle

Capillary electrophoresis separates ions based on their electrophoretic mobility with the use of an applied voltage. The separation occurs in a narrow capillary tube filled with an electrolyte. The ions migrate through the capillary at different speeds depending on their charge-to-mass ratio. Once separated, the ions are introduced into the mass spectrometer, where they are ionized, and their mass-to-charge ratios are measured.

Instrumentation

The CE-MS system consists of several key components:

• Capillary Electrophoresis Unit: This includes the capillary, buffer reservoirs, and high-voltage power supply.
• Interface: The interface connects the CE unit to the mass spectrometer. Common interfaces include electrospray ionization (ESI) and matrix-assisted laser desorption/ionization (MALDI).
• Mass Spectrometer: This includes the ion source, mass analyzer, and detector. Types of mass analyzers used in CE-MS include quadrupole, time-of-flight (TOF), and ion trap.

Applications

CE-MS is used in various applications, including:

• Proteomics: For the analysis of proteins and peptides.
• Metabolomics: For the study of metabolites in biological samples.
• Pharmaceutical Analysis: For the characterization of drugs and their metabolites.
• Clinical Diagnostics: For the detection of biomarkers in disease states.

Advantages

CE-MS offers several advantages over other analytical techniques:

• High separation efficiency due to the narrow capillary.
• Low sample and reagent consumption.
• High sensitivity and specificity provided by the mass spectrometer.
• Ability to analyze small and large molecules.

Challenges

Despite its advantages, CE-MS also faces some challenges:

• Limited sample loading capacity.
• Complexity in interfacing CE with MS.
• Requirement for highly skilled operators.

See Also

• Electrophoresis
• Liquid chromatography–mass spectrometry
• Gas chromatography–mass spectrometry
• Analytical chemistry