Capillary Electrophoresis Essay

By Jonas Wilson

Types of Capillary Electrophoresis

In the evolution of techniques used to separate molecules based on their electrophoretic mobility, capillary electrophoresis has been fine-tuned in order to obtain optimal results for varying experiments. For the purposes of this article, six main forms of capillary electrophoresis, branching from two main subsets, one of which is further subdivided into two subdivisions, will be discussed.

Generally, the two main subsets of capillary electrophoresis are a continuous system capillary electrophoresis and a discontinuous system capillary electrophoresis. The discontinuous system essentially ensures that a sample is kept in a distinct zone, which is partitioned by two dissimilar electrolytes.

These micelles are imperative for their polar negativity, which causes a pull towards the positive pole. The molecules that are hydrophobic (water hating) will tend to aggregate with the micelle, while those that are hydrophilic (water loving) will move fairly quickly through the solution. The key parameters for this technique are pH, surfactant concentration, any additives and the polymer coatings that are used on the capillary wall.

Capillary zone electrophoresis (CZE)

This is the most commonly used capillary electrophoresis method of the six being discussed. CZE, also known as free solution capillary electrophoresis, is a separation technique that predominantly takes into account the ratio of the particle’s charge to mass, where those with large charge to mass ratio separate from the rest first; therefore, the larger the ratio, the quicker the separation.

In addition to the electrophoretic mobility of the molecules, CZE is heavily dependent on the application of constant field strength throughout the capillary and on the pH of the buffer solution. CZE is an excellent choice of technique to employ in cases where there are very small pI (isoelectric point) differences in protein