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Issue 3, 2009
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Electrode array detector for microchip capillary electrophoresis

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Abstract

Selectivity and resolution for analyses conducted using microfluidic devices can be improved by increasing the total number of individual detection elements in the device. Here, a poly(dimethylsiloxane) capillary electrophoresis microchip was fabricated with an integrated electrode array for selective detection of small molecules. Eight individually addressable gold electrodes were incorporated in series after a palladium current decoupler in the separation channel of an electrophoresis microchip. The electrode array device was characterized using a mixture of biologically relevant analytes and xenobiotics: norepinephrine, 4-aminophenol, acetaminophen, uric acid, and 3,4-dihydroxyphenylacetic acid. Separation efficiencies as high as 9000 ± 1000 plates (n = 3) for 3,4-dihydroxyphenylacetic acid and limits of detection as low as 2.6 ± 1.2 µM (n = 3) for norepinephrine were obtained using this device. After characterizing the performance of the device, potential step detection was conducted at the array electrodes and selective detection achieved based upon differences in redox potentials for individual analytes. Utilization of potential step detection was particularly advantageous for resolving co-migrating species; resolution of 3,4-dihydroxy-L-phenylalanine from acetaminophen using potential control was demonstrated. Finally, a human urine sample was analyzed using potential step detection to demonstrate the applicability of this device for complex sample analysis.

Graphical abstract: Electrode array detector for microchip capillary electrophoresis

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Publication details

The article was received on 17 Sep 2008, accepted on 17 Nov 2008 and first published on 03 Dec 2008


Article type: Paper
DOI: 10.1039/B816289A
Analyst, 2009,134, 486-492

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    Electrode array detector for microchip capillary electrophoresis

    R. E. Holcomb, J. R. Kraly and C. S. Henry, Analyst, 2009, 134, 486
    DOI: 10.1039/B816289A

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