Capillary Electrophoresis Techniques in Analytical Chemistry

Capillary electrophoresis (CE) encompasses a family of high-efficiency electromigration methods that separate ionic and neutral species within narrow, fused-silica or polymeric capillaries under an applied electric field. Separation arises from differences in electrophoretic mobility and the background electroosmotic flow, with a range of modes—zone electrophoresis, gel sieving, isoelectric focusing, isotachophoresis and micellar electrokinetic chromatography—providing tailored resolution for peptides, proteins, nucleic acids, small organic molecules and inorganic ions. Advances in capillary coatings, buffer chemistries and detector interfaces have enabled routine coupling with mass spectrometry, laser-induced fluorescence and contactless conductivity detectors, extending CE’s reach into proteomics, glycomics, metabolomics, environmental monitoring and clinical diagnostics. Instrument miniaturisation, microfluidic integration and novel gel matrices now permit real-time assays, two-dimensional separations and point-of-care platforms, underpinning CE’s emergence as a versatile tool in analytical chemistry globally.

Research from Nature Portfolio

Recent developments have yielded a palmtop high-speed CE system that integrates picolitre-scale sample injection, a short capillary for rapid separations, an onboard high-voltage supply and orthogonal laser-induced fluorescence detection within a compact, low-cost chassis. With dimensions under 100 × 75 × 77 mm and a sub-nanomolar limit of detection, the device achieves high-efficiency separations of amino acids, chiral enantiomers, DNA fragments and proteins. Its application in rapid genotyping assays illustrates the potential for portable CE instruments in clinical and field-based analyses without compromising analytical performance.

Capillary Electrophoresis Techniques in Analytical Chemistry publication trend

The graph below shows the total number of articles in capillary electrophoresis techniques in analytical chemistry across all publications each year (not limited to Nature Index journals).

Technical terms

Capillary electrophoresis (CE): Technique for separating analytes in narrow capillaries under an electric field based on differences in charge-to-size ratio and electroosmotic flow.

Electroosmotic flow (EOF): Bulk solvent movement induced by an electric field acting on charged capillary walls, carrying analytes toward the detector.

Micellar electrokinetic chromatography (MEKC): CE variant using micelles to enable separation of neutral compounds by differential partitioning into the micellar phase.

Capillary zone electrophoresis (CZE): Basic CE mode where analytes migrate in a uniform buffer zone, separating by electrophoretic mobility.

Capillary gel electrophoresis (CGE): Sieving-based CE technique incorporating a gel matrix to resolve molecules by effective size.

Capillary isoelectric focusing (CIEF): Separation of amphoteric species within a pH gradient until each reaches its isoelectric point.

Laser-induced fluorescence (LIF) detection: Sensitive CE detection method using laser excitation to monitor fluorescently labelled analytes.

CE-MS coupling: Integration of capillary electrophoresis with mass spectrometric detection, providing high resolution and structural identification.

References

1. A Low-Cost Palmtop High-Speed Capillary Electrophoresis Bioanalyzer with Laser Induced Fluorescence Detection. Scientific Reports (2018).
2. Direct Injection Electrospray Ionization Mass Spectrometry (ESI‐MS) Analysis of Proteins with High Matrix Content:Utilizing Taylor–Aris Dispersion. Angewandte Chemie International Edition (2024).
3. Capillary Gel Electrophoresis of Proteins: Historical overview and recent advances. TrAC Trends in Analytical Chemistry (2023).
4. Gels in Microscale Electrophoresis. Annual Review of Analytical Chemistry (2023).
5. In-house-made capillary electrophoresis instruments coupled with contactless conductivity detection as a simple and inexpensive solution for water analysis: a case study in Vietnam. Environmental Science Processes & Impacts (2015).