Study on electrochemical behavior of tryptophan at a glassy carbon electrode modified with multi-walled carbon nanotubes embedded cerium hexacyanoferrate

Electrochemical behavior of cerium hexacyanoferrate (CeHCF) incorporated on multi-walled carbon nanotubes (MWNTs) modified GC electrode is investigated by scanning electron microscopy (SEM) and electrochemical techniques. The CeHCF/MWNT/GC electrode showed potent electrocatalytic activity toward the electrochemical oxidation of tryptophan in phosphate buffer solution (pH 7.0) with a diminution of the over-potential of 240 mV. The anodic peak currents increased linearly with the concentration of tryptophan in the range of 2.0 x 10(-7) to 1.0 x 10(-4) M with a detection limit of 2.0 x 10(-8) M (at a S/N = 3). And the determination of tryptophan in pharmaceutical samples was satisfactory. (C) 2007 Elsevier B.V. All rights reserved.