Effect of PVP on the electroosmotic mobility of wet‐etched glass microchannels

We present an experimental study on the effect of polymer PVP on EOF mobility of microchannels wet etched into optical white soda lime glass, also known as C rown glass. We performed experiments to evaluate the effect of PVP concentration and p H on EOF mobility. We used on‐chip capillary zone electrophoresis and a neutral fluorescent dye as a passive marker to quantify the electroosmotic flow. We performed experiments under controlled conditions by varying p H from 5.2 and 10.3 and concentration of PVP from 0 to 2.0% w/w at constant ionic strength (30 mM). Our experiments show that PVP at concentrations of 1.0% or above very effectively suppress EOF at low pH (6.6). At high pH of 10.3, PVP has a much weaker suppressing effect on EOF and increasing its concentration above about 0.5% showed negligible effect on EOF mobility. Finally, we briefly discuss the effects of p H on using PVP as an adsorbed coating. Our experiments provide useful guidelines on choosing correct p H and concentration of PVP for effective EOF suppression in glass channels.