Two-dimensional strong cation-exchange liquid chromatography/reversed-phase pressurized capillary electrochromatography for separation of complex samples

A 2-D separation platform was constructed using micro strong cation-exchange liquid chromatography (μ-SCXLC) and reversed-phase pressurized capillary electrochromatography (RP-pCEC) for the analysis of complex samples. Samples were fractionated by the first-dimension μ-SCXLC with a linear solvent gradient and then injected into the second-dimension RP-pCEC for further separation. The μ-SCXLC/RP-pCEC 2-D system with three separation mechanisms, namely strong cation-exchange, reversed-phase chromatography and electrophoresis, provided high selectivity, high resolution and high peak capacity compared to one-dimensional chromatographic approaches. Separation effectiveness of this 2-D system was demonstrated by the analysis of different kinds of complex samples, such as traditional Chinese medicine Cortex Phellodendri, bovine serum albumin (BSA) tryptic digest and real serum tryptic digest. A theoretical peak capacity of approximately 1200 was achieved, which proves its promising potential for the separation and analysis of complex samples.