L-Glutamine-assisted synthesis of ZnO oatmeal-like/silver composites as an electrochemical sensor for Pb 2+ detection

Anal Bioanal Chem. 2019 Jan;411(2):517-526. doi: 10.1007/s00216-018-1476-x. Epub 2018 Nov 29.

Abstract

We report a green synthesis of oatmeal ZnO/silver composites in the presence of L-glutamine as an electrochemical sensor for Pb2+ detection. The synthesis was performed via the direct reduction of Ag+ in the presence of L-glutamine in NaOH. X-ray diffraction indicated that the Ag+ was completely reduced to metallic Ag. The field emission scanning electron microscopy (FESEM) and energy dispersive X-ray results confirmed an oatmeal-like morphology of the ZnO with the presence of Ag. The FESEM images showed the effect of L-glutamine on the ZnO morphology. The EIS results confirmed a significant decrease in the charge transfer resistance of the modified glassy carbon electrode due to the presence of Ag. From the differential pulse voltammetry results, a linear working range for the concentration of Pb2+ between 5 and 6 nM with LOD of 0.078 nM (S/N = 3) was obtained. The sensitivity of the linear segment is 1.42 μA nM-1 cm-2. The presence of L-glutamine as the capping agent and stabilizer decreases the size of Ag nanoparticles and prevents the agglomeration of ZnO, respectively. Graphical abstract ᅟ.

Keywords: L-Glutamine; Lead sensor; Silver nanoparticles.

MeSH terms

  • Avena / chemistry*
  • Electrochemical Techniques / instrumentation*
  • Glutamine / chemistry*
  • Lead / chemistry*
  • Silver
  • Water Pollutants
  • Zinc Oxide

Substances

  • Water Pollutants
  • Glutamine
  • Lead
  • Silver
  • Zinc Oxide