Impact of pore structural parameters on column performance and resolution of reversed-phase monolithic silica columns for peptides and proteins.

In this work, monolithic silica columns with the C4, C8, and C18 chemistry and having various macropore diameters and two different mesopore diameters are studied to access the differences in the column efficiency under isocratic elution conditions and the resolution of selected peptide pairs under reversed-phase gradient elution conditions for the separation of peptides and proteins. The columns with the pore structural characteristics that provided the most efficient separations are then employed to optimize the conditions of a gradient separation of a model mixture of peptides and proteins based on surface chemistry, gradient time, volumetric flow rate, and acetonitrile concentration. Both the mesopore and macropore diameters of the monolithic column are decisive for the column efficiency.

Sulphonic acid strong cation-exchange restricted access columns in sample cleanup for profiling of endogenous peptides in multidimensional liquid chromatography. Structure and function of strong cation-exchange restricted access materials.

In this work, the pore structural parameters and size exclusion properties of LiChrospher strong cation-exchange and reverse phase restricted access materials (RAM) are analysed. The molecular weight size exclusion limit for polystyrenes was found to be about 17.7 kDa, while for standard proteins, the molecular weight size exclusion limit was higher, at approximately 25 kDa.

Synthesis and characterization of polyrotaxane-based polymeric continuous beds for capillary electrochromatography.

The continuous bed technique with its attractive features, such as fritless design, one-step in situ synthesis, low back pressure and no need for pressurising the electrode vessels to suppress bubble formation was applied to form polyrotaxane-based stationary phases for capillary electrochromatography (CEC). Rotaxanes are synthesized from two classes of substances, namely linear reactive monomers and inert cyclic compounds. Upon polymerisation, a gel forms with the cyclic molecules mechanically immobilized (see Fig.

A new easy-to-prepare homogeneous continuous electrochromatographic bed for enantiomer recognition.

Completely homogeneous polyacrylamide-based gels were used for capillary electrochromatography (CEC) of drug enantiomers. Like continuous beds (also called continuous polymer rods, silica rods, monoliths) they do not require frits to support the bed because it is covalently linked to the capillary wall. A long lifetime is an important feature of the beds.