Analytical Sciences

Influence of the pH on Separating DNA by High-Speed Microchip Electrophoresis

Tomo OSAFUNE,* Hideya NAGATA,* and Yoshinobu BABA*^,**

*Department of Medicinal Chemistry, Faculty of Pharmaceutical Sciences, The University of Tokushima, CREST, Japan Science and Technology Corporation (JST), Tokushima 770-8505, Japan
**Single-molecule Bioanalysis Laboratory, National Institute of Advanced Industrial Science and Technology (AIST), Takamatsu 761-0395, Japan

Various factors are critical in resolving DNA molecules at high speed, including the separation medium, concentration, composition, and pH of the buffer, as well as the electric field strength. To this study, considered the composition of a buffer and the difference in the pH, while paying attention to whether the separation ability changes in the microchip electrophoresis of DNA. DNA separation was particularly affected by both the buffer composition and the pH. Under the optimal microchip electrophoresis conditions that were determined in this study, an improved resolution of a wider range of DNA fragment sizes was achieved. Moreover, the total separation time decreased from 240 s to 100 s. Thus, by simplifying and improving the DNA electrophoresis in the microchip, this technique is now widely applicable to several different scientific fields.

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