Sensing and Bio-Sensing Research (Nov 2017)

Simultaneous determination of caffeine and theophylline using square wave voltammetry at poly(l-aspartic acid)/functionalized multi-walled carbon nanotubes composite modified electrode

  • Birhanu Mekassa,
  • Merid Tessema,
  • Bhagwan Singh Chandravanshi

Journal volume & issue
Vol. 16
pp. 46 – 54

Abstract

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A simple and reproducible poly(l-aspartic acid)/functionalized multi-walled carbon nanotubes composite modified glassy carbon electrode, P(LAsp)/f-MWCNTs/GCE, was constructed for simultaneous determination of caffeine and theophylline using square wave voltammetry. The electrode preserves and combines the properties of the individual modifiers synergistically. The electrochemical response of P(LAsp)/f-MWCNTs/GCE was characterized by cyclic voltammetry. A significant enhancement in the peak current response of CF and TP were observed accompanied with a negative shift in peak potential at the composite modified electrode compared to the bare electrode. The prepared P(LAsp)/f-MWCNTs/GCE exhibited excellent SWV response towards the simultaneous detection of CF and TP in the range of 1–150 and 0.1–50μM with limit of detection of 0.28 and 0.02μM (S/N=3), respectively. Real sample analysis has been successfully carried out in green tea, blood serum and pharmaceutical formulation of Panadol extra samples, which revealed good recovery results, 92.0–106%. The proposed sensor also displayed good selectivity, repeatability and reproducibility with appreciable long-term stability, indicating the feasibility and reliability. Keywords: Poly(l-aspartic acid)/functionalized multi-walled carbon nanotubes composite modified electrode, Square wave voltammetry, Simultaneous determination caffeine and theophylline, Green tea, Blood serum, Panadol extra