Mechanical Engineering Department, Stanford University, CA, USA.
Electrophoresis. 2012 Nov;33(21):3259-62. doi: 10.1002/elps.201200336. Epub 2012 Oct 12.
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 Crown glass. We performed experiments to evaluate the effect of PVP concentration and pH 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 pH 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 pH on using PVP as an adsorbed coating. Our experiments provide useful guidelines on choosing correct pH and concentration of PVP for effective EOF suppression in glass channels.
我们进行了一项关于聚合物 PVP 对微通道电渗流（EOF）迁移率影响的实验研究，该微通道是通过湿刻工艺在光学白钠钙玻璃（也称为冕牌玻璃）上形成的。我们进行了实验，以评估 PVP 浓度和 pH 值对 EOF 迁移率的影响。我们使用片上毛细管区带电泳和中性荧光染料作为被动标记物来定量电渗流。我们通过在恒定离子强度（30 mM）下从 pH 值 5.2 到 10.3 以及 PVP 浓度从 0 到 2.0% w/w 变化来控制条件进行实验。我们的实验表明，在低 pH 值（6.6）下，浓度为 1.0%或更高的 PVP 可非常有效地抑制 EOF。在 pH 值为 10.3 时，PVP 对 EOF 的抑制作用要弱得多，而将其浓度增加到 0.5%以上对 EOF 迁移率几乎没有影响。最后，我们简要讨论了 pH 值对使用 PVP 作为吸附涂层的影响。我们的实验为在玻璃通道中有效抑制 EOF 提供了有关选择正确 pH 值和 PVP 浓度的有用指南。
