The use of 3 and 12 micron particulate stationary phases in voltage-assisted micro-LC for the separation of mixtures containing neutral, basic and acidic analytes

The application of voltage-assisted micro-LC using CEC instrumentation (capable of applying 1.2 MPa of pressure to supplement the electroosomotic flow) has been demonstrated. This has been achieved by the use of 100 pm x 24 cm capillaries packed with 12 Pm stationary phase material; alternatively 7.5 cm capillaries packed with 3 mum material using the short-end injection approach with reversed polarity can be used. The paper highlights how both approaches can be successfully employed to control the separation selectivity of a range of mixtures containing acidic, basic and neutral components by the concomitant addition of voltage (either positive or negative) to the applied micro-LC flow.