Methods and compositions for electophoretic separations

A method for analyzing at least one analyte, the method comprising:

• introducing a composition into a separation channel, wherein the composition comprises at least one carrier ampholyte, an amine buffer present in an amount effective to produce a non-linear pH gradient, and at least one analyte of interest;
• applying an electric field across the separation channel to establish the non-linear pH gradient and separating the composition via isoelectric focusing, generating at least one focused analyte peak;
• mobilizing the at least one focused analyte peak;
• and
• wherein the presence of the amine buffer and the resulting non-linear pH gradient provide improved separation of the at least one analyte relative to that attained in a method which does not comprise the amine buffer.