ABSTRACT
An electrochemical phosphate sensor based on zirconium and reduced graphene oxide modified pencil graphite electrode (Zr/rGO-PGE) is proposed. The XRD, CV and EIS confirmed that GO was partially reduced on the PGE. Scanning electron microscopy (SEM) exhibited the layered and wrinkled structures for the rGO-PGE and Zr/rGO-PGE, respectively. Cyclic voltammetry showed the immobilized rGO was highly stable and had high activity toward zirconium adsorption. The prepared electrode was used for the electrochemical determination of phosphate. Based on the optimum condition using differential pulse voltammetry, the limit of detection and sensitivity for phosphate was obtained as [0.011(± 0.004) µM] (S/N = 3) and [622.4(± 9.6) µA µM-1 cm-2], respectively. The sensor was successfully evaluated for phosphate determination in human serum samples. In practical terms, the construction of this sensor was exceptionally simple, fast, cost effective and reproducible.
Subject(s)
Blood Chemical Analysis/instrumentation , Graphite/chemistry , Oxides/chemistry , Phosphates/blood , Zirconium/chemistry , Electrochemistry , Electrodes , Humans , Oxidation-Reduction , Phosphates/chemistryABSTRACT
Synthesis of noble metal nanoparticles (NPs) on modified graphene oxide with biocompatible polymers has attracted significant due to their unique properties and various applications. In this research, covalent-modified graphene oxide (MGO) with diacid terminated poly (ethylene glycol) (PEG) was used as a substrate and stabilizing of Au (Ñ). The reduction of MGO-Au (Ñ) complex with hydrazine monohydrate under reflux condition obtained biocompatible reduced MGO (rMGO)-Au NPs. Diacid terminated PEG obtained from the reaction of PEG with succinic anhydride in the presence of N,N- dicyclohexylcarbodiimide (DCC) and 4-methylamino pyridine (DMAP) was attached to GO sheets to prevent from the aggregation of rMGO sheets and Au NPs. The resulting aqueous suspension was characterized through UV-vis, FT-IR, Raman, XRD, DLS-zeta potential, SEM, EDX and TEM. Furthermore, nanocomposite showed good catalytic behavior in Betti reaction- synthesis of 1-(α-aminoalkyl)-2-naphthols. The favorable properties of colloidal nanocomposite were attributed to the stable and well distribution Au NPs on rMGO.
Subject(s)
Biocompatible Materials/chemistry , Graphite/chemistry , Nanocomposites/chemistry , Aminopyridines/chemistry , Catalysis , Colloids/chemistry , Dicyclohexylcarbodiimide/chemistry , Metal Nanoparticles/chemistry , Microscopy, Electron, Scanning , Naphthols/chemical synthesis , Naphthols/chemistry , Oxides/chemistry , Polyethylene Glycols/chemistry , Spectrophotometry, Ultraviolet , Spectroscopy, Fourier Transform Infrared , Spectrum Analysis, Raman , Succinic Anhydrides/chemistry , X-Ray DiffractionABSTRACT
In this research, a new type of chemically modified graphene oxide (GO) was synthesized based a silane ligand and then used as substrate and stabilizing for the synthesis of monodispersed and small Ag nanoparticles (NPs). First, ligand molecules were successfully grafted onto the surface of GO (LGO) and then, active groups of LGO could effectively interact with Ag ions. The reduction of Ag ions and LGO sheets was carried out by hydrazine under reflux. The resulted nanocomposite was fully characterized by different techniques. Furthermore, the antibacterial behavior of nanocomposite was studied against E. coli and S. aureus. The results showed that nanocomposite exhibits good antibacterial activity against E. coli and S. aureus and also S. aureus showed greater resistance than the E. coli strains against the LG/Ag nanocomposite.
Subject(s)
Nanocomposites , Anti-Bacterial Agents , Escherichia coli , Graphite , Ligands , Oxides , Silanes , Silver , Staphylococcus aureusABSTRACT
In this work, an environmentally friendly method was applied for the synthesis of aqueous suspension of l-cysteine modified Ag nanoparticles (NPs)-decorated reduced graphene oxide (rGO) nanocomposite. l-cysteine played a triple role as reducing agent, stabilizer and linker of Ag NPs onto the surface of rGO. The resultant nanocomposite was characterized by Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction studies (XRD), zeta potential, Raman spectroscopy, scanning electron microscopy (SEM) and energy dispersive analysis of X-ray (EDX). Meanwhile, minimum inhibitory concentration (MIC), minimum bacterial concentration (MBC), agar well diffusion and cyclic voltammetry (CV) techniques were used for the investigation of antibacterial and electrocatalytic behaviors of the nanocomposite, respectively. The obtained nanocomposite showed not only enhanced electrocatalytic activity for glucose but also excellent antibacterial activity against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus).
