Microfluidics and Nanofluidics

, Volume 11, Issue 2, pp 227–233 | Cite as

Enhanced electrophoresis separation of non-electroactive amino acids on poly(dimethylsiloxane) microchip coupled with direct electrochemical detection on a copper electrode

  • Ruping Liang
  • Li Wang
  • Xiangying Meng
  • Jingwu Wang
  • Jianding Qiu
Short Communication

Abstract

Electrochemical determination of amino acids on a Cu electrode was established as an attractive scheme for non-electroactive amino acids after microchip electrophoresis separation. Five amino acids (arginine, proline, histidine, valine, and serine) achieved efficient separation within 60 s on a titanium dioxide nanoparticles (TiO2 NPs) coated poly(dimethylsiloxane) (PDMS) microchip, and then successfully detected on a Cu electrode in end-channel detection mode. In the slightly basic borate medium, anodic currents occur for amino acids due to their ability to form Cu(II) complexes and thereby enhance the electrochemical dissolution of Cu electrode substrate. The increase of the anodic current measured is proportional to the amino acid concentration added to the solution, and therefore, enables direct detection of non-electroactive amino acids on the Cu electrode. The detection limits (S/N = 3) for arginine, proline, histidine, valine, and serine were measured to be 7, 6, 5, 6, and 5 μM, respectively, with the linear ranges all from 25 to 500 μM. In addition, compared with the native PDMS microchip, resolutions and separation efficiencies of amino acids on the modified microchip were considerably enhanced with the theoretical plate numbers of 8.9 × 103, 6.6 × 104, 4.8 × 104, 5.6 × 104, and 4.4 × 104 plates m−1, respectively. The proposed Cu electrode response demonstrated good reproducibility and stability, with no apparent loss of response for periods as long as 4 weeks.

Keywords

Non-electroactive amino acids Microchip electrophoresis Copper electrode Poly(dimethylsiloxane) 

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Copyright information

© Springer-Verlag 2011

Authors and Affiliations

  • Ruping Liang
    • 1
  • Li Wang
    • 1
  • Xiangying Meng
    • 1
  • Jingwu Wang
    • 1
  • Jianding Qiu
    • 1
  1. 1.Department of ChemistryNanchang UniversityNanchangPeople’s Republic of China

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