Liu Y, Fanguy J C, Bledsoe J M, Henry C S
Department of Chemistry, Mississippi State University, 39762, USA.
Anal Chem. 2000 Dec 15;72(24):5939-44. doi: 10.1021/ac000932l.
Poly(dimethylsiloxane) (PDMS) capillary electrophoresis (CE) microchips were modified by a dynamic coating method that provided stable electroosmotic flow (EOF) with respect to pH. The separation channel was coated with a polymer bilayer consisting of a cationic layer of Polybrene (PB) and an anionic layer of dextran sulfate (DS). According to the difference in charge, PB- and PB/ DS-coated channels supported EOF in different directions; however, both methods of channel coating exhibited a pH-independent EOF in the pH range of 5-10 due to chemical control of the effective zeta-potential. The endurance of the PB-coated layer was determined to be 50 runs at pH 3.0, while PB/DS-coated chips had a stable EOF for more than 100 runs. The effect of substrate composition and chip-sealing methodology was also evaluated. All tested chips showed the same EOF on the PB/DS-coated channels, as compared to uncoated chips, which varied significantly. No significant variation for separation and electrochemical detection of dopamine and hydroquinone between coated and uncoated channels was observed.
聚二甲基硅氧烷（PDMS）毛细管电泳（CE）微芯片通过一种动态涂层方法进行了改性，该方法能提供相对于pH稳定的电渗流（EOF）。分离通道用由聚凝胺（PB）阳离子层和硫酸葡聚糖（DS）阴离子层组成的聚合物双层进行了涂层处理。根据电荷差异，PB涂层通道和PB/DS涂层通道支持不同方向的电渗流；然而，由于有效zeta电位的化学控制，两种通道涂层方法在pH 5 - 10范围内均表现出与pH无关的电渗流。PB涂层的耐久性在pH 3.0时被确定为50次运行，而PB/DS涂层芯片在超过100次运行中具有稳定的电渗流。还评估了基底组成和芯片密封方法的影响。与未涂层芯片相比，所有测试芯片在PB/DS涂层通道上显示出相同的电渗流，而未涂层芯片的电渗流变化显著。在涂层通道和未涂层通道之间，未观察到多巴胺和对苯二酚的分离及电化学检测有显著差异。
