Carbon nanotube detectors for microchip CE: comparative study of single-wall and multiwall carbon nanotube, and graphite powder films on glassy carbon, gold, and platinum electrode surfaces.
The performance of microchip electrophoresis/electrochemistry system with carbon nanotube (CNT) film electrodes was studied. Electrocatalytic activities of different carbon materials (single-wall CNT (SWCNT), multiwall CNT (MWCNT), carbon powder) cast on different electrode substrates (glassy carbon (GC), gold, and platinum) were compared in a microfluidic setup and their performance as microchip electrochemical detectors was assessed. An MWCNT film on a GC electrode shows electrocatalytic effect toward oxidation of dopamine (E(1/2) shift of 0.09 V) and catechol (E(1/2) shift of 0.19 V) when compared to a bare GC electrode, while other CNT/carbon powder films on the GC electrode display negligible effects. Modification of a gold electrode by graphite powder results in a strong electrocatalytic effect toward oxidation of dopamine and catechol (E(1/2) shift of 0.14 and 0.11 V, respectively). A significant shift of the half-wave potentials to lower values also provide the MWCNT film (E(1/2) shift of 0.08 and 0.08 V for dopamine and catechol, respectively) and the SWCNT film (E(1/2) shift of 0.10 V for catechol) when compared to a bare gold electrode. A microfluidic device with a CNT film-modified detection electrode displays greatly improved separation resolution (R(s)) by a factor of two compared to a bare electrode, reflecting the electrocatalytic activity of CNT.
Pumera
Martin
M
ICYS, National Institute for Materials Science, Tsukuba, Ibaraki, Japan. PUMERA.Martin@nims.go.jp
Merkoçi
Arben
A
Alegret
Salvador
S
D002244:Carbon; D002396:Catechols / Q000302:isolation & purification; D004298:Dopamine / Q000302:isolation & purification; D004563:Electrochemistry; D046209:Electrophoresis, Microchip / Q000295:instrumentation*; D006046:Gold; D006108:Graphite; D008839:Microelectrodes; D033401:Microscopy, Acoustic; D037742:Nanotubes, Carbon; D010984:Platinum
D002396:Catechols; D037742:Nanotubes, Carbon; D010984:Platinum; D002244:Carbon; D006046:Gold; D006108:Graphite; C034221:catechol; D004298:Dopamine