Capacitively coupled contactless conductivity detection with dual top-bottom cell configuration for microchip electrophoresis.
An optimized capacitively coupled contactless conductivity detector for microchip electophoresis is presented. The detector consists of a pair of top-bottom excitation electrodes and a pair of pickup electrodes disposed onto a very thin plastic microfluidic chip. The detection cell formed by the electrodes is completely encased and shielded in a metal housing. These approaches allow for the enhancement of signal coupling and extraction from the detection cell that result in an improved signal-to-noise-ratio and detection sensitivity. The improved detector performance is illustrated by the electrophoretic separation of six cations (NH(4) (+), K(+), Ca(2+), Na(+), Mg(2+), Li(+)) with a detection limit of approximately 0.3 microM and the analysis of the anions (Br(-), Cl(-), NO(2) (-), NO(3) (-), SO(4) (2-), F(-)) with a detection limit of about 0.15 microM. These LODs are significantly improved compared with previous reports using the conventional top-top electrode geometry. The developed system was applied to the analysis of ions in bottled drinking water samples.
Institute of Materials Research & Engineering, Agency for Science, Technology and Research (A*STAR) 3 Research Link, Singapore.
Kambiz A
KA
Mahabadi
Isabel
I
Rodriguez
Chee Y
CY
Lim
Devendra K
DK
Maurya
Peter C
PC
Hauser
Nico F
NF
de Rooij
D000838:Anions / Q000032:analysis*; D001628:Beverages / Q000032:analysis; D002412:Cations / Q000032:analysis*; D004326:Drinking; D004553:Electric Conductivity; D004566:Electrodes; D046209:Electrophoresis, Microchip / Q000295:instrumentation / Q000379:methods*; D057230:Limit of Detection
D000838:Anions; D002412:Cations