l-Glutamine-assisted synthesis of ZnO oatmeal-like/silver composites as an electrochemical sensor for Pb2+ detection

• Published in: Analytical and bioanalytical chemistry 2019-01, Vol.411 (2), p.517-526
• Main Authors: Mahmoudian, Mohammad Reza, Basirun, Wan Jefrey, Woi, Pei Meng, Yousefi, Ramin, Alias, Yatimah
• Format: Article
• Language: English
• Subjects: Analytical Chemistry; Biochemistry; Characterization and Evaluation of Materials; Charge transfer; Chemical sensors; Chemistry; Chemistry and Materials Science; Composite materials; Direct reduction; Electrochemistry; Field emission microscopy; Food Science; Glassy carbon; Glutamine; Laboratory Medicine; Lead; Monitoring/Environmental Analysis; Morphology; Nanoparticles; Research Paper; Scanning electron microscopy; Silver; Sodium hydroxide; Synthesis; X-ray diffraction; Zinc oxide
• ISSN: 1618-2642; 1618-2650
• DOI: 10.1007/s00216-018-1476-x

We report a green synthesis of oatmeal ZnO/silver composites in the presence of l -glutamine as an electrochemical sensor for Pb 2+ 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 Pb 2+ 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