Conductivity properties of carrier ampholyte pH gradients in isoelectric focusing.
The conductivity properties of natural pH gradient created by carrier ampholytes were studied during the process of isoelectric focusing (IEF). IEF was performed in capillaries (10-30 mm long) or in microchips with the same channel length. A 10-30x reduction of the conductivity of the separation medium was observed during the establishment of pH gradient. Results obtained using different IEF voltages indicate that there is a nonlinear relationship between the conductivity of an established pH gradient and the applied electric field. Our theoretical analysis using a simplified model generated values that reasonably agree with the experimental data. In addition, we found that above a certain electric field ( approximately 300 V/cm), resolution does not increase with the applied voltage as predicated; we observed band-broadening and gel breakdown. The approach presented in this work can be used for optimization of the IEF separation and judicious selection of IEF conditions.
Stoyanov
Alexander V
AV
Department of Mechanical and Aerospace Engineering, McKnight Brain Institute, University of Florida, Gainesville 32611, USA.
Das
Champak
C
Fredrickson
Carl K
CK
Fan
Z Hugh
ZH
D000665:Ampholyte Mixtures; D004553:Electric Conductivity; D006863:Hydrogen-Ion Concentration; D007525:Isoelectric Focusing / Q000379:methods*; D046210:Microfluidic Analytical Techniques
D000665:Ampholyte Mixtures