Ta(2)O(5)/rGO Nanocomposite Modified Electrodes for Detection of Tryptophan through Electrochemical Route

l-tryptophan is one of the eight kinds of essential amino acids for sustainable human life activity. It is common to detect the concentration of tryptophan in human serum for diagnosing and preventing brain related diseases. Herein, in this study, GCE (glassy carbon electrode) modified by Ta(2)O(5)-reduced graphene oxide (-rGO) composite (Ta(2)O(5)-rGO-GCE) is synthesized by the hydrothermal synthesis-calcination methods, which is used for detecting the concentration of tryptophan in human serum under the as-obtained optimal detection conditions. As a result, the obtained Ta(2)O(5)-rGO-GCE shows larger electrochemical activity area than other bare GCE and rGO-GCE due to the synergistic effect of Ta(2)O(5) NPs and rGO. Meanwhile, Ta(2)O(5)-rGO-GCE shows an excellent response to tryptophan during the oxidation process in 0.1 M phosphate buffer solution (pH = 6). Moreover, three wide linear detection range (1.0–8.0 μM, 8.0–80 μM and 80–800 μM) and a low limit of detection (LOD) of 0.84 μM (S/N = 3) in the detection of tryptophan are also presented, showing the larger linear ranges and lower detection limit by employing Ta(2)O(5)-rGO-GCE. Finally, the as-proposed Ta(2)O(5)-rGO-GCE with satisfactory recoveries (101~106%) is successfully realized for the detection of tryptophan in human serum. The synthesis of Ta(2)O(5)-rGO-GCE in this article could provide a slight view for the synthesis of other electrochemical catalytic systems in detection of trace substance in human serum.