Fabrication and evaluation of single- and dual-channel (Pi-design) microchip electrophoresis with electrochemical detection.
A new dual-channel microchip capillary electrophoresis (MCE) has been developed on glass substrates for the first time with electrochemical detection. Dual-channel (called Pi-design) as well as single-channel microchips have been fabricated on soda-lime glass using photolithography, wet etching and thermal bonding. Moreover, a laser writing system has been applied for the fabrication of photomasks with the different microchip designs (single- and dual-channel configurations). The microfabricated channels have been characterized by optical, confocal and scanning electron microscopy. The resulting single- and dual-channel microchips have been evaluated using an end-channel amperometric detector based on one (single-channel) or two (dual-channel) 100-mum gold wires aligned at the outlet of the separation channel. Parameters affecting the separation of several phenolic compounds (dopamine, p-aminophenol and hydroquinone) have been studied in the glass microchips. Thus, the influence of separation voltage, detection potential and background electrolyte has been examined in the single-channel microchip. Different total length microchannel has been compared. Furthermore, the possibility of carrying out two simultaneous measurements has been demonstrated in the new dual-channel microchip electrophoresis. The injection format has been checked and resulted to be critical, in such a way that a special and new form is employed for obtaining simultaneous signals at both channels. Analytical characteristics, such as sensitivity and reproducibility have been evaluated and resulted very adequate.
Pozo-Ayuso
Diego F
DF
Departamento de Física, Universidad de Oviedo, 33007 Oviedo, Asturias, Spain.
Castaño-Alvarez
Mario
M
Fernández-la-Villa
Ana
A
García-Granda
Miguel
M
Fernández-Abedul
M Teresa
MT
Costa-García
Agustín
A
Rodríguez-García
Jose
J
D004563:Electrochemistry / Q000379:methods*; D046209:Electrophoresis, Microchip / Q000295:instrumentation / Q000379:methods*; D018613:Microscopy, Confocal; D008855:Microscopy, Electron, Scanning; D015203:Reproducibility of Results