Design of separation length and electric field strength for high-speed DNA electrophoresis

Effective length calibration method for processing the fluorescence signal detected by charge-coupled device in capillary electrophoresis

A novel method named effective length calibration method has been developed to process the fluorescence signal detected by charge-coupled device during capillary electrophoresis. The new method treated each pixel as an individual point detector, and effectively binned a large number of pixels into a final electropherogram without losing the narrow detection window defined by a single pixel. Capillary electrophoresis separations of DNA were carried out and detected by charge-coupled device and conventional detector (photomultiplier tube). Detection properties including signal-to-noise ratio, peak width, detection frequency, and tilt of detector were investigated. It was found that the new method achieved much higher signal-to-noise ratio and smaller peak width than the conventional detector did. A Detection width of 0.5 μm was easily achieved.

Theoretical investigation on the performance of DNA electrophoresis under programmed step electric field strength: Two-step condition

Programmed step electric field strength is a simple-to-use technique that has already been reported to be effective to enhance the efficiency or speed of DNA electrophoresis. However, a global understanding and the details of this technique are still vague. In this paper, we investigated the influence of programmed step electric field strength by theoretical calculation and concentrated on a basic format named as two-step electric field strength. Both subtypes of two-step electric field strength conditions were considered. The important parameters, such as peak spacing, peak width, resolution, and migration time, were calculated in theory to understand the performance of DNA electrophoresis under programmed step electric field strength. The influence of two-step electric field strength on DNA electrophoresis was clearly revealed on a diagram of resolution versus migration time. Both resolution and speed of DNA electrophoresis under two-step electric field strength conditions are simply expressed by the shape of curves in the diagram. The possible shapes of curve were explored by calculation and shown in this paper. The subtype II of two-step electric field strength brings drastic variation on the resolution. Its limitations of enhancement and deterioration of resolution were predicted in theory.