Cobalt Hexacyanoferrate-modified Graphene Platform Electrodeand Its Electrochemical Sensing toward Hydrogen Peroxide / 分析化学

A large-area graphene platform electrode (GPE) was fabricated by transferring the chemical vapor deposition (CVD) graphene grown on Cu foils to polyethylene terephthalate (PET) substrates with the aid of polymethyl-methacrylate (PMMA).Then cobalt hexacyanoferrate (CoHCF) was electrodeposited on the GPE by cyclic voltammetry to obtain a CoHCF/GPE.The morphology and electrochemical properties of this electrode were studied by scanning electron microscope (SEM), electrochemical impedance spectroscopy (EIS) and the electrochemical measurements.Results showed that the electrode had favorable sensing effect toward H2O2.On the basis of this, a new nonenzyme H2O2 sensor was constructed.Under the optimal experimental conditions, the proposed sensor had a quick response to the addition of H2O2 (about 2 s) with a wide linear rang (5 × 10-3-1.2 mmol/L) and a low detection limit (7.1 nmol/L).This sensor was easy to fabricate and showed excellent stability and anti-interference ability.

Estudo matemático de estabilidade do desempenho do sistema [Fe(CN)6]3-/[Fe(CN)6]4- como mediador na eletrorredução de nitrito, com fins eletroanalíticos / The mathematical stability study for the work of the [Fe(CN)6]3-/[Fe(CN)6]4- system as a mediator in nitrite electroreduction, used for electroanalytical means

O desempenho do sensor de nitrito, baseado no elétrodo, modificado pelo sistema de hexacianoferratos (II) e (III) como mediador, foi descrito matematicamente, sendo o modelo matemático correspondente analisado mediante a teoria de estabilidade lineal e análise de bifurcações. O modelo foi comparado com os análogos e com os sistemas experimentais.

The work of nitrite sensor, based on the electrode, modified by the system of hexacianoferrates (II) and (III) as mediator, was mathematically described, and the corresponding mathematical model was analyzed by means of linear stability theory and bifurcation analysis. The model was compared with its analogues and experimental systems.

Construction of Electrochemical Sensor Based on Praseodymium Hexacyanoferrate Modified Graphite Electrode and Its Application for Cysteine Determination / 分析化学

Praseodymium hexacyanoferrate film was modified on the graphite electrode by cyclic voltammetry in the solution of PrCl_3 and K_3Fe(CN)_6. Its electrochemical properties, including the influence of different scan rates, ions, and K~+ concentrations on the film, were studied. The membrane was characterized by IR and XPS. In IR spectrum, the vibration of cyano group verified from the formation of the film on the electrode. In XPS spectrum, the splitting of Fe2p_(1/2) )and Fe2p_(3/2)) showed that the valence of iron has been changed in the film formation, and a proper electropolymerization mechanism was put forward. The results showed the PrHCF film have some electrocatalytic activity to the oxidation of cysteine. The detection conditions for cysteine such as the potential and pH were also discussed.