Fast, high‐resolution (capillary) electrophoresis in buffers designed for high field strengths
- 1 January 1995
- journal article
- research article
- Published by Wiley in Electrophoresis
- Vol. 16 (1), 584-594
- https://doi.org/10.1002/elps.1150160195
Abstract
Capillary electrophoresis in conventional buffers and in 50 μ capillaries permits field strengths as high as 300–500 V/cm with acceptably low thermal zone deformation. However, still higher field strengths (up to at least 2000 V/cm) can be applied without a decrease in resolution if the experiments are performed in the buffers described in this paper. Characteristic of these buffers is their low electrical conductivity and yet satisfactory buffering capacity accomplished either (i) by selecting buffer constituents of relatively high molecular weight and small net charge or (ii) by fractionation of carrier ampholytes (originally introduced for isoelectric focusing experiments) into a series of narrow pH range fractions and using these fractions as buffers, or (iii) by selecting an ampholyte with two acidic groups and one basic group (or one acidic group and two basic groups) and with a pI value close to two of its pK values. In such buffers, aromatic carboxylic acids and proteins used as model substances could be analyzed rapidly. For instance, albumin and transferrin were separated at 30000 V (1.99 μA) in 15 cm long fused silica capillaries (50 μ ID) within 40 s and the carboxylic acids within 25 s. The resolution was similar to that obtained at standard voltage (5000 V; 0.33 μA), but the analysis time was reduced sixfold. Although not verified experimentally we also suggest the use of relatively high-molecular-weight polyoxyethylene derivatized with one acidic group (for instance, boric acid) and one basic group (an amine), both having the same pK value, which should afford both a very high buffering capacity and very low electrical conductivity (at low buffer concentrations).Keywords
This publication has 13 references indexed in Scilit:
- β+-Selective radiodetector for capillary electrophoresisJournal of Chromatography A, 1993
- Zone broadening in electrophoresis with special reference to high‐performance electrophoresis in capillaries: An interplay between theory and practiceElectrophoresis, 1990
- Protein separation in pH gradients using free‐flow electrophoretic apparatus I. The borate‐mannitol pH gradientsElectrophoresis, 1985
- Displacement electrophoresis : Experiments with countrflow of electrolyteJournal of Chromatography A, 1970
- Free zone electrophoresisChromatographic Reviews, 1967
- Gegenstromionophorese—I: Prinzip und theoretische grundlagenTalanta, 1966
- Isoelectric Fractionation, Analysis, and Characterization of Ampholytes in Natural pH Gradients. II. Buffering Capacity and Conductance of Isoionic Ampholytes.Acta Chemica Scandinavica, 1962
- A simple theory of electrophoresis: Determination of the equivalent weight of colloid electrolytesRecueil des Travaux Chimiques des Pays-Bas, 1952
- PROTEINS, AMINO ACIDS AND PEPTIDES as Ions and Dipolar IonsThe American Journal of the Medical Sciences, 1943
- The influence of electrolyte concentration on the electrophoretic mobility of egg albuminTransactions of the Faraday Society, 1940