Preparation of Multiwalled Carbon Nanotubes: Electrochemically Treated Pencil Graphite Electrodes for Nanomolar Detection of L-Tryptophan in Complex Samples

摘要

The present work reports a sensitive and simple sensor based on an electrochemically treated pencil graphite electrode (pre-PGE) modified with multi-walled carbon nanotubes (MWCNTs) for electrochemical determination of L-tryptophan (L-Try) detection in the presence of uric acid. Electrochemical and physical characterizations of the MWCNTs/pre-PGE were investigated using cyclic voltammetry (CV), Electrochemical impedance spectroscopy (EIS), and scanning electron microscopy (SEM) techniques. Under the optimized conditions, the linear working range was 0.030-200.0 mu M with a limit of detection of 9.0 nM using the differential pulse adsorptive stripping voltammetry (DPAdSV) method. The proposed sensor exhibited good sensitivity, repeatability, reproducibility, and stability. The MWCNTs/pre-PGE were successfully applied to L-Try determination in commercial poly-amino acid supplements with good recovery and accuracy.