PULSED-FIELD CAPILLARY ELECTROPHORESIS - OPTIMIZING SEPARATION PARAMETERS WITH MODEL MIXTURES OF SULFONATED POLYSTYRENES

The electrophoretic transport Of high molecular weight charged solutes , both flexible and stiff polymers, has been studied by capillary elec trophoresis under constant-field and pulsed-field conditions. Sulfonat ed polystyrenes were used as model solutes in different entangled poly mer solutions. First, changes of the end-to-end distance vectors of fl exible polymers were examined through the mobility/potential-gradient curves. Under pulsed-field conditions, the influence of different puls e shapes, frequencies, and amplitudes of forward and backward pulses o n the electrophoretic mobilities of model solutes was studied. Resolut ion of the mixture components was strongly affected by changes in freq uency of both sine-wave and square-wave pulses. The experimental resul ts obtained under pulsed-field conditions are roughly in agreement wit h the existing theories of electrophoretic transport.