Effect of Caged Fluorescent Dye on the Electroosmotic Mobility in Microchannels

We report on measurements of electroosmotic mobility in polymer microchannels and silica capillaries with and without the addition of a caged fluorescein dye to the buffer. For PMMA microchannels, the mobility was found to increase from (2.6 +0.1) × 10^-4 cm^2 V^-1 s^-1 to (4.6 +- 0.1) × 10^-4 cm^2 V^-1 s^-1 upon addition of 1.2 mmol/L of caged dye. For PC microchannels, the mobility increased from (4.3 +- 0.2) × 10^-4 cm^2 V^-1 s^-1 to (5.4 +- 0.1) × 10^-4 cm^2 V^-1 s^-1 upon addition of caged dye. For PDMS microchannels, the mobility increased from (4.3 +- 0.2) × 10^-4 cm^2 V^-1 s^-1 to (6.4 +0.5) × 10^-4 cm^2 V^-1 s^-1 upon addition of caged dye. For fused-silica capillaries, the mobility ((5.5 +- 0.2) × 10^-4 cm^2 V^-1 s^-1) was unaffected by the addition of the caged dye.