Highly selective and sensitive electrochemical sensor for l-cysteine detection based on graphene oxide/multiwalled carbon nanotube/manganese dioxide/gold nanoparticles composite

• Synthesis and application of GO/CCNTs/AuNPs@MnO2 as a sensor for l-cysteine analysis
• The synthesized polymer had a flower-like structure with high surface and good specific catalyze –SH groups.
• The propose sensor showed high selectivity and good sensitivity.

A highly selective and sensitive electrochemical sensor for detection of l-cysteine based on a graphene oxide/carboxylated multiwalled carbon nanotube/manganese dioxide/gold nanoparticles composite (GO/CCNTs/AuNPs@MnO2) was developed. The property of the glassy carbon electrode which was modified by GO/CCNTs/AuNPs@MnO2 contributed to increasing the sensing surface area and the electronic transmission rate. Besides, the addition of MnO2 could effectively improve the selectivity and specificity of l-cysteine determination. The morphology and composition of GO/CCNTs/AuNPs@MnO2 were characterized by scanning electron microscope, energy dispersive spectrometer, fourier transform infrared spectroscopy and X-ray diffractometer and the results evidenced that GO/CCNTs/AuNPs@MnO2 flower-like structure was efficiently synthesized. The determination results of l-cysteine indicated that the surface area, electronic transmission rate and sensitivity of GO/CCNTs/AuNPs@MnO2 sensor were highly increased. Under the optimal conditions, the electrochemical sensor exhibited excellent analytical performance with good selectivity, reproducibility and stability. The linear range of l-cysteine was from 1.0 × 10− 8 to 7.0 × 10− 6 mol L− 1 and the detection limit was 3.4 × 10− 9 mol L− 1 (3δ). The proposed electrochemical sensor was successfully applied to the determination of trace l-cysteine in spiked water samples.

Schematic diagram of GO/CNTs/AuNPs@MnO2 composites apply to the electrode.Figure optionsDownload as PowerPoint slide