Analytical Sciences

Abstract − Analytical Sciences, 31(11), 1151 (2015).

Zone Sharpening of Peptides in Pressurized Capillary Electrochromatography Using Dynamic pH Junction
Hideomi UMEDA, Shinya KITAGAWA, and Hajime OHTANI
Department of Materials Science and Engineering, Graduate School of Engineering, Nagoya Institute of Technology, Gokiso, Showa, Nagoya 466-8555, Japan
In HPLC, analytes injected into a separation column broaden naturally during the separation procedure. In this paper, analyte zone sharpening of peptides was achieved in pressurized capillary electrochromatography, which is a separation method that combines capillary HPLC and capillary electrophoresis (CE), by employing dynamic pH junction for CE. When the pH of the mobile phase was altered from basic to acidic in a step gradient, the analyte peptides were focused at the basic/acidic interface with the application of voltage. The effect of both pH and pressurized flow velocity on the zone sharpening was investigated. With the proposed method, the peak height of angiotensin II, [Asn1, Val5]-angiotensin II, and angiotensin III were enhanced 12, 10, and 12 times, respectively. Selective peak zone sharpening for angiotensin II was also demonstrated.