Electric field gradient focusing using a variable width polyaniline electrode

• Published in: Electrophoresis 2012-11, Vol.33 (21), p.3254-3258
• Main Authors: Trickett, Christopher A., Henderson, Rowan D., Guijt, Rosanne M., Breadmore, Michael C.
• Format: Article
• Language: English
• Subjects: Aniline Compounds - chemistry; Conducting polymer; Electric field gradient focusing; Electric Impedance; Electrodes; Fluorescent Dyes - chemistry; Isoelectric Focusing - instrumentation; Isoelectric Focusing - methods; Microscopy, Fluorescence; Models, Chemical; Polyaniline; Quinine - chemistry; Rhodamines - chemistry; Stacking
• ISSN: 0173-0835; 1522-2683
• DOI: 10.1002/elps.201200335

A new approach for electric field gradient focusing (EFGF) based on the use of a variable‐width polyaniline (PANI) electrode is demonstrated. The electrode was created by patterning a PANI nanofibre film using a 635‐nm laser and a computer‐controlled XY stage. The electrode consisted of 16 segments of varying width, ranging from 200 to 5000 μm in 320 μm increments, with the resistance changing approximately 20‐fold from 3881 to 198 kΩ at each extreme, respectively. Application of a voltage across the electrode established a voltage gradient resulting in a non‐linear distribution of electrophoretic velocities along the microchannel. When balanced with a combination of hydrodynamic flow and EOF, the variable‐width PANI electrode could be used for the concentration and separation of two cationic dyes, rhodamine 6G and quinine, which were concentrated by at least threefold within 10 min.