Capillary Electrophoresis


Capillary zone electrophoresis is a fully automated approach to electrophoresis that uses narrow‐bore (10–100 μm) fused‐silica capillaries as a separation chamber and online detection of analytes. The increased heat dissipation allows the delivery of high field strengths (100–500 V cm−1). The use of minute sample amounts and volumes and the very fast analysis times make it an attractive technique in modern bioanalysis.

Keywords: capillary electrophoresis; temporal thermal gradients; single‐strand chain polymorphism; isoelectric buffers

Figure 1.

A typical commercial capillary zone electrophoresis system (not drawn to scale). The extremities of the capillary are immersed in small vials containing the background electrolyte and two platinum wires connected to a high‐voltage power supply that can deliver up to 30000 V. The detector, placed close to one extremity of the capillary, can be either an ultraviolet/visible system (provided with filters or a monochromator) or a diode array detector. Some instruments are provided with a laser‐induced fluorescence detector. The carousel for sample loading and the computer that controls the whole unit are not shown. EOF: electroendoosmotic flow.

Figure 2.

Capillary zone electrophoresis of the β39 PCR‐amplified fragment in 50 mM phosphate buffer in the presence of 7 M urea (apparent pH of 3.0). Conditions were Bio Rad Bio Focus 3000; capillary length, 40 cm; inner diameter, 50 μm; injection, 5 s at 10 kV. Separations were done at 150 V cm−1 at 25°C. (a) Control, wild‐type β39; (b) β39 from heterozygous individual. Note the full resolution between the wild‐type and mutant strands in (b). (Reproduced with permission from Gelfi et al., .)

Figure 3.

Capillary zone electrophoresis of tryptic digests of β‐casein. (a) Conditions were: inner diameter, 100 μm; capillary length, 37 cm; electrolyte, 80 mM phosphate buffer (pH 2.0). Separations were done at 110 V cm−1 (current 85 μA) and detection was at 214 nm. The three main peaks are fragment β‐CN (114–169), pI 6.1; fragment β‐CN (49–97), pI 6.93; and fragment β‐CN (33–48), pI 3.95. (b) Conditions were: inner diameter, 100 μm; capillary length, 37 cm; bath, 50 mM isoelectric aspartic acid (pH roughly the pI value of 2.77) with 0.5% hydroxyethyl cellulose and 5% trifluoroethanol. Separations were done at 600 V cm−1 (current 58 μA). (Reproduced with permission from Righetti et al..)



Colón LA, Reynolds KJ, Alicea‐Maldonado R and Fermier AM (1997) Advances in capillary electrochromatography. Electrophoresis 18: 2162–2174.

Gebauer P and Bocek P (1997) Recent applications and developments of capillary isotachophoresis. Electrophoresis 18: 2154–2161.

Gelfi C, Viganò A, Carta P, et al. (2000a) Screening for the β‐39 mutation by capillary electrophoresis in free solution in strongly acidic, isoelectric buffers. Electrophoresis 21: 780–784.

Gelfi C, Viganò A, Curcio M, et al. (2000b) Single‐strand conformation polymorphism analysis by capillary zone electrophoresis in neutral pH buffer. Electrophoresis 21: 785–791.

Jacobson SC and Ramsey JM (1998) Microfabricated chemical separation devices. In: Khaledi MG (ed.) High‐performance Capillary Electrophoresis, pp. 613–633. New York: John Wiley.

Moring SE (1996) Buffers, electrolytes and additives for capillary electrophoresis. In: Righetti PG (ed.) Capillary Electrophoresis in Analytical Biotechnology, pp. 37–60. Boca Raton, FL: CRC Press.

Righetti PG and Gelfi C (1997) Recent advances in capillary electrophoresis of DNA fragments and PCR products in poly(N‐substituted acrylamides). Analytical Biochemistry 244: 95–207.

Righetti PG, Gelfi C, Bossi A, et al. (2000) Capillary electrophoresis of proteins and peptides in isoelectric buffers. Electrophoresis 21: 4046–4053.

Righetti PG, Gelfi C and Conti M (1997) Current trends in capillary isoelectric focusing of proteins. Journal of Chromatography B 699: 91–104.

Takagi T (1997) Capillary electrophoresis in presence of sodium dodecyl sulfate and a sieving medium. Electrophoresis 18: 2239–2242.

Terabe S, Shibata M and Miyashita Y (1989) Chiral separation by electrokinetic chromatography with bile salt micelles. Journal of Chromatography 480: 403–411.

Further Reading

The complete history and developments of CZE can be followed in a series of special issues of Journal of Chromatography dedicated to the proceedings of meetings on high‐performance capillary electrophoresis, of which the first meeting took place in Boston, MA, in April 1989.

(1989) Journal of Chromatography 480: 1–435.

(1990) Journal of Chromatography 516: 1–298.

(1991) Journal of Chromatography 559: 1–559.

(1992) Journal of Chromatography 608: 1–427.

(1993) Journal of Chromatography A 652: 1–571.

(1994) Journal of Chromatography A 680: 1–685.

(1995) Journal of Chromatography A 716: 1–410.

(1995) Journal of Chromatography A 717: 1–427.

(1996) Journal of Chromatography A 744: 1–355.

(1996) Journal of Chromatography A 745: 1–299.

(1997) Journal of Chromatography A 781: 1–565.

(1998) Journal of Chromatography A 817: 1–383.

(1999) Journal of Chromatography A 838: 1–320.

(1999) Journal of Chromatography A 853: 1–576.

(2000) Journal of Chromatography A 894: 1–355.

(2000) Journal of Chromatography A 895: 1–371.

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Righetti, Pier Giorgio(Sep 2005) Capillary Electrophoresis. In: eLS. John Wiley & Sons Ltd, Chichester. [doi: 10.1038/npg.els.0005336]