Comprehensive off-line, two-dimensional liquid chromatography. Application to the separation of peptide digests

The separation of the peptide digests of myoglobin and bovine serum albumin was performed with an off-line combination of two commercial, conventional HPLC columns. The first column was packed with a strong ion exchanger and eluted with a KC1 gradient. The second column was packed with particles of C-18-bonded silica and eluted with an acetonitrile gradient The conditional peak capacities of the 2D separations achieved exceed 7000 under the experimental conditions investigated. This performance is achieved at the cost of an analysis time of the order of 28 hours. Possible improvements to the separation method described here are discussed.