Fractionation of carrier ampholytes for isoelectric focusing

A simple method for fractionating synthetic carrier ampholytes is reported, based on the principle of continuous-flow isoelectric focusing in gel-stabilized layers. An 8% ampholyte solution, encompassing the pH range 3-9.5, is separated into 12 fractions in a chamber filled with Sephadex G-100 by a continuous-flow technique. We are thus able to obtain ampholytes of narrow pH range, encompassing approximately 2 pH units, whose resolving power is comparable with that obtained with commercial Ampholine covering similar pH ranges.