Author(s): Liu X, Luo L, Ding Y, Ye D
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Abstract A novel poly-glutamic acid (PGA) film modified carbon paste electrode (CPE) incorporating carbon nanotubes (CNTs) was first prepared for the determination of l-tryptophan (l-Trp). Scanning electron microscopy and Fourier transform infrared spectroscopy were applied for characterization of the surface morphology of the modified electrodes and cyclic voltammetry was used to investigate the electrochemical properties of the proposed electrode towards the oxidation of l-Trp. Optimization of the experimental parameters was performed with regard to pH, ratio of CNTs, concentration of glutamic acid, electro-polymerization cycles, accumulation time and concentration of sodium dodecylbenzene sulfonate. The linearity between the oxidation peak current and the l-Trp concentration was obtained in the range of 5.0×10(-8) to 1.0×10(-4)M with a detection limit of 1.0×10(-8)M (S/N=3) and the sensitivity was calculated to be 1143.79μA∙mM(-1)∙cm(-2). In addition, the PGA modified CPE incorporating CNTs displayed high selectivity, good stability and reproducibility, making it suitable for the routine analysis of l-Trp in clinical use. Copyright © 2011 Elsevier B.V. All rights reserved.
This article was published in Bioelectrochemistry
and referenced in Journal of Biosensors & Bioelectronics