title: Disposable twin gold electrodes for amperometric detection in capillary electrophoresis.
abstract: We describe a simple and easy way to construct gold microelectrodes for amperometric detection in capillary electrophoresis (CE). The gold microelectrodes, in single or twin sets, were obtained from recordable compact discs (gold-sputtered type), which present highly reproducible surface characteristics. The performance of these electrodes was evaluated by using a home-made CE equipment. The basic steps for the electrode construction are: drawing on a microcomputer; laser printing of the design on wax paper; heat-transfer of the toner onto the gold surface of a peeled recordable compact disc (CD-R); etching of the gold layer from unprinted regions; removal of the toner with a solvent; sealing of unused electrode areas with varnish. One electrode at a time was connected to a potentiostat (or two, to a bipotentiostat) and operated in a wall jet configuration relative to the CE capillary outlet. The amperometric signals were integrated for quantification purposes. Repetitive injections (n = 10) of a mixture containing iodide, ascorbic acid, dipyrone, and acetaminophen (20, 200, 500, and 100 microM), presented relative standard deviations of 2.9, 4.5, 6.1, and 4.0%, respectively. For these analytes, the detection limits (S/N = 3, 30 s of 100 mm hydrodynamic injection) were 0.1, 0.5, 3.1, and 1.1 microM, respectively.
authors.affiliation: Instituto de QuímicaUniversidade de São Paulo, São Paulo, SP, Brazil.
authors.forename: Eduardo M
authors.initials: EM
authors.lastname: Richter
authors.forename: José A
authors.initials: JA
authors.lastname: Fracassi da Silva
authors.forename: Ivano G Rolf
authors.initials: IG
authors.lastname: Gutz
authors.forename: Claudimir L
authors.initials: CL
authors.lastname: do Lago
authors.forename: Lúcio
authors.initials: L
authors.lastname: Angnes
mesh_terms: D004209:Disposable Equipment; D004563:Electrochemistry / Q000295:instrumentation / Q000379:methods; D004566:Electrodes; D019075:Electrophoresis, Capillary / Q000295:instrumentation / Q000379:methods*; D006046:Gold
chemical_list: D006046:Gold