Capillary electrophoretic separations of proteins using carrier ampholytes.

Capillary separations of proteins using carrier ampholytes are performed between an anolyte and a catholyte of same pH (pH 3). Depending upon the concentration of carrier ampholytes used, two different separation processes take place. At a 10% concentration, the high-resolution separation of six model proteins is achieved, which can be described as a transient capillary isoelectric focusing (cIEF) system moving isotachophoretically.

On-target fraction collection for the off-line coupling of capillary isoelectric focusing with matrix-assisted laser desorption/ionization mass spectrometry.

In the present work, we describe a collection system for the off-line coupling of capillary isoelectric focusing (CIEF) with matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) mass spectrometry. In this system, the capillary effluent is directly deposited in fractions onto the MALDI target via the use of a sheath liquid. The collected fractions are subsequently supplemented with matrix and further analysed by MALDI-TOF mass spectrometry for mass assignment.