title: Electric field gradient focusing using a variable width polyaniline electrode.
abstract: 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.
authors.affiliation: Australian Centre for Research on Separation Science, School of Chemistry, University of Tasmania, Hobart, Tasmania, Australia.
authors.forename: Christopher A
authors.initials: CA
authors.lastname: Trickett
authors.forename: Rowan D
authors.initials: RD
authors.lastname: Henderson
authors.forename: Rosanne M
authors.initials: RM
authors.lastname: Guijt
authors.forename: Michael C
authors.initials: MC
authors.lastname: Breadmore
mesh_terms: D000814:Aniline Compounds / Q000737:chemistry*; D017097:Electric Impedance; D004566:Electrodes; D005456:Fluorescent Dyes / Q000737:chemistry; D007525:Isoelectric Focusing / Q000295:instrumentation* / Q000379:methods*; D008856:Microscopy, Fluorescence; D008956:Models, Chemical; D011803:Quinine / Q000737:chemistry; D012235:Rhodamines / Q000737:chemistry
chemical_list: D000814:Aniline Compounds; D005456:Fluorescent Dyes; D012235:Rhodamines; C416807:polyaniline; C026188:rhodamine 6G; D011803:Quinine