Beckman-Coulter has recently introduced the ProteomeLab PF2D for 2-D liquid separation of protein samples. The system features separation in the first dimension by chromatofocusing, followed by RP chromatography in the second dimension, allowing the analysis of complex proteomics samples. When used by the standard protocol, reproducibility and column life times are limited, making the use of the instrument very costly. We here present an improved protocol for chromatofocusing, which enhances column life by at least fivefold.