CHARACTERIZATION AND APPLICATION OF STRONG ION-EXCHANGE MEMBRANE ADSORBERS AS STATIONARY PHASES IN HIGH-PERFORMANCE LIQUID-CHROMATOGRAPHY OF PROTEINS

Filtration membranes carrying strong cation- or anion-exchange groups on their surface were evaluated for their potential as membrane adsorb er stationary phases in the high-performance liquid chromatography of proteins. The membranes are commercially available and can be obtained inserted into ready-to-use filter holders. Owing to their thinness (1 70-290 mu m), the pressure drop of the membranes is extremely low. Flo w-rates of up to 65 mi min(-1) per unit became thus possible. The low pressure drop of a single membrane layer also permitted an effortless scaling up, as a stack of several membranes or filter units could be u sed, if necessary. Sample distribution, protein binding capacity, elut ion conditions, separation efficiency and recovery were investigated a s a function of the flow-rate. The time required for the separation of certain protein mixtures could be reduced to less than 1 min. Appropr iate conditions were defined for the separation of human serum and for the isolation of subtilisin Carlsberg and beta-galactosidase from cel l culture supernatants.