Fabrication of disposable voltammetric electronic tongues by using Prussian Blue films electrodeposited onto CD-R gold surfaces and recognition of milk adulteration

A new approach to fabricate a disposable electronic tongue is reported. The fabrication of the disposable sensor aimed the integration of all electrodes necessary for measurement in the same device. The disposable device was constructed with gold CD-R and copper sheets substrates and the sensing elements were gold, copper and a gold surface modified with a layer of Prussian Blue. The relative standard deviation for signals obtained from 20 different disposable gold and 10 different disposable copper electrodes was below 3.5%. The performance, electrode materials and the capability of the device to differentiate samples were evaluated for taste substances model, milk with different pasteurization processes (homogenized/pasteurized, ultra high temperature (UHT) pasteurized and UHT pasteurized with low fat content) and adulterated with hydrogen peroxide. In all analysed cases, a good separation between different samples was noticed in the score plots obtained from the principal component analysis (PCA). Crown Copyright (C) 2008 Published by Elsevier B.V. All rights reserved.

Electronic Perspective on the Electrochemistry of Prussian Blue Films

The derivative of the voltabsommetric scans, together with previous nano-electrogravimetric and X-ray diffraction results, allow different electrochemical processes to be distinguished during the Prussian blue (PB) voltammetric scan. Potassium, proton, and hydrated proton counterions involved in PB electrochemistry are related here to the electrochemical reactions of specific Fe sites. Potassium counterions show two different sites for their insertion: one located in the crystalline framework and another in ferrocyanide vacancies. From the monitoring of electroactive Fe sites, the covalent-exchange model is suggested as one of the first approaches to explain the origin of the PB magnetic ordering observed at room temperature during voltammetric scanning.

Fabrication and electrochemical characterization of electrostatic assembly of polyelectrolyte-functionalized ionic liquid and Prussian blue ultrathin films

Polyelectrolyte-functionalized ionic liquid (PFIL) and Prussian blue (PB) nanoparticles were used to fabricate ultrathin films on the ITO substrate through electrostatic layer-by-layer assembly method. Multilayer growth was examined by UV-vis spectroscopy and cyclic voltammetry. The resulting ITO/(PFIL/PB)n electrode showed two couples of well-defined redox peaks and good electrocatalytical activity towards the reduction of hydrogen peroxide.

Layer-by-layer assembly of carbon nanotubes and Prussian blue nanoparticles: A potential tool for biosensing devices

A promising method for assembling carbon nanotubes (CNTs) and poly(diallyldimethylammonium chloride) protected Prussian blue nanoparticles (P-PB) to form three-dimensional (3D) nanostructured films is proposed. The electrostatic interaction, combined with layer-by-layer self-assembly (LBL), between negatively charged CNTs and positively charged P-PB is strong enough to drive the formation of the 3D nanostructured films. Thus, prepared multilayer films were characterized by ultraviolet-visible-near-infrared spectroscopy (UV-vis-NIR), scanning electron microscopy (SEM) and cyclic voltammetry (CV).

Synthesis and characterization of Prussian blue@platinum nanoparticle hybrids from a mixture solution of platinum nanocatalyst and ferric ferricyanide

In the present study, platinum nanoparticles modified with Prussian blue (PB) have been synthesized by a heterogeneous catalytic reaction. Transmission electronic microscopy (TEM) confirmed the deposition of nanoclusters around the Surfaces of platinum particles, and spectroscopic studies verified that the molecular composition of the nanoclusters was dominantly PB and a minority of platinum ferricyanide. Thus, it was shown that the platinum particles behaved not only as catalysts for the growth of PB, but also as a reactant to generate a PB analogue complex.

Prussian Blue/Multiwalled Carbon Nanotube Hybrids: Synthesis, Assembly and Electrochemical Behavior

Prussian blue/carbon nanotube (PB/CNT) hybrids with excellent dispersibility in aqueous solutions were synthesized by adding CNTs to an acidic solution of Fe3+, [Fe(CN)(6)](3-) and KCl. Fourier transform infrared spectroscopy, UV-vis absorption spectroscopy and scanning electron microscopy were employed to confirm the formation of PB/CNT hybrids. The PB nanoparticles formed on the CNT surfaces exhibit a narrow size distribution and an average size of 40 nm. The present results demonstrate that the selective reduction of Fe3+ to Fe2+ by CNTs is the key step for PB/CNT hybrid formation. The subsequent fabrication of the PB/CNT hybrid films was achieved by layer-by-layer technique. The thus-prepared PB/CNT hybrid films exhibit electrocatalytic activity towards H2O2 reduction.

Functionalization of single-walled carbon nanotubes with Prussian blue

Chemical functionalization of single-walled carbon nanotubes (SWNTs) has constructed plenty of new structures with ample new properties into them. But the modification was often confined to organic molecules, either by covalence or non-covalence. In this report, SWNTs were successfully functionalized with one kind of electroactive inorganic compounds: Prussian blue (PB). And the molecular interactions between them were firstly investigated. Interestedly, pi-pi stacking interaction coupled with ionic interaction was found between SWNTs and PB. The electrochemical properties of SWNTs-PB were also investigated. It would pave a new pathway to manipulate molecular entities of SWNTs by cooperation with functional inorganic electroactive compounds.

Assembly of Prussian blue onto SiO2 nanoparticles and carbon nanotubes by electrostatic interaction

Prussian blue (PB) was modified onto surface of SiO2 nanoparticles and multiwall carbon nanotubes (MWNTs) by electrostatic assembled method. SiO2 nanoparticles and MWNTs firstly modified by polyelectrolyte exhibited positive charges and negative charged PB could be assembled onto them. UV-vs spectroscopy, Fourier transform infrared spectroscopy (FTIR), transmission electron microscopy (TEM), field-emitted scanning electron microscopy (FE-SEM) and electrochemical methods were used to characterize these composite nanomaterials. TEM and FE-SEM images showed that PB was easily assembled onto polyelectrolyte modified SiO2 nanoparticles and MWNTs. Moreover, PB on the surface of nanomaterials was stable and still kept its intrinsic electrochemical properties and high electrocatalytic activity towards hydrogen peroxide.

An electrochemical study of prussian blue microcrystallines mixed in PEO400 polymer electrolyte by solid-state voltammetry

The electrochemistry of Prussian blue mixed in a polymer medium containing MClO4 (M = Li+, Na+, K+, TBA(+)) as the supporting electrolyte was studied by means of solid-state voltammetry. This approach is new in Prussian blue studies. The behavior of PB in polymer electrolytes is somewhat similar to the well-known behavior for an electrochemically synthesized PB film in aqueous media. Besides, K+, Li+ and Na+ ions can also transport through the crystal of PB because of its zeolitic nature. The transport of TBA(+) ions is possible. Kinetic control lies in the diffusion of cations in and out of the lattice of Prussian blue. Reduction waves of Prussian blue depend on both the size and type of cations. PB is very stable upon electrochemical cycling in polymer electrolytes and air. This system may be used in rechargeable batteries and electrochromic devices.

AMPEROMETRIC BIOSENSORS BASED ON THE IMMOBILIZATION OF OXIDASES IN A PRUSSIAN BLUE FILM BY ELECTROCHEMICAL CODEPOSITION

Prussian blue has been formed by cyclic voltammetry onto the basal pyrolytic graphite surface to prepare a chemically modified electrode which provides excellent electrocatalysis for both oxidation and reduction of hydrogen peroxide. It is found for the first time that glucose oxidase or D-amino oxidase can be incorporated into a Prussian blue film during its electrochemical growth process. Two amperometric biosensors were fabricated by electrochemical codeposition, and the resulting sensors were protected by coverage with a thin film of Nafion. The influence of various experimental conditions was examined for optimum analytical performance. The glucose sensor responds rapidly to substrates with a detection limit of 2 x 10(-6) M and a linear concentration range of 0.01-3 mM. There was no interference from 2 mM ascorbic acid or uric acid. Another (D-amino acid) sensor gave a detection limit of 3 x 10(-5) M D-alanine, injected with a linear concentration range of 7.0 x 10(-5)-1.4 x 10(-2) M. Glucose and D-amino acid sensors remain relatively stable for 20 and 15 days, respectively. There is no obvious interference from anion electroactive species due to a low operating potential and excellent permselectivity of Nafion.

ELECTROCATALYTIC OXIDATION OF ASCORBIC-ACID AT A PRUSSIAN BLUE FILM MODIFIED MICRODISK ELECTRODE

The preparation and the behaviour of a Prussian Blue (PB) film on a platinum microdisk electrode has been described. Electrocatalytic oxidation of ascorbic acid has occurred at the PB film modified microelectrode. This shows a typical example of a modified microelectrode in electrocatalysis following our previous theoretical studies (J. Electroanal. Chem., 309 (1991) 103) and the related catalytic reaction rate constant was determined.

Structure effects of self-assembled Prussian blue confined in highly organized mesoporous TiO(2) on the electrocatalytic properties towards H(2)O(2) detection

Here we report the derivatization of mesoporous TiO(2) thin films for the preparation of H(2)O(2) amperometric sensors. The coordination of the bifunctional ligand 1,10 phenantroline, 5,6 dione on the surface Ti(IV) ions provides open coordination sites for Fe(II) cations which are the starting point for the growth of a layer of Prussian blue polymer. The porous structure of the mesoporous TiO(2) allows the growth, ion by ion of the coordination polymer. Up to four layer of Prussian blue can be deposit without losing the porous structure of the film, which results in an enhanced response of these materials as H(2)O(2) sensors. These porous confined PB modified electrodes are robust sensors that exhibit good reproducibility, environmental stability and high sensitivity towards H(2)O(2) detection. (C) 2010 Elsevier B.V. All rights reserved.

Voltammetric determination of persulfate anions using an electrode modified with a Prussian blue film

Prussian blue [PB, iron(III) hexacyanoferrate(II)] films are effective for the electrocatalysis of the persulfate (peroxodisulfate)/sulfate redox system. This has been exploited in the voltammetric determination of persulfate anions using a PB-modified platinum disc electrode. A linear correlation between electrocatalytic current and persulfate concentration was found for the range 5 x 10(-5) to 3 x 10(-3) mol dm(-3), using 0.100 mol dm(-3) potassium chloride as supporting electrolyte at pH 4. This analytical method has the advantages of speed and ease of operation in relation to traditional titrimetric methods for persulfate determination. The applicability of the method to the determination of persulfate in a commercial hair bleaching 'booster' product is demonstrated. (C) 2000 Elsevier B.V. B.V. All rights reserved.

Changeover during in situ compositional modulation of hexacyanoferrate (Prussian Blue) material

This paper describes the importance of (H2O)(6) clusters in controlling the properties of hexacyanoferrate (Prussian Blue) materials. A careful in situ study of compositional changes by using electrogravimetric techniques (in ac and dc modes) in hexacyanoferrates containing K+ alkali metals reveals the existence of a changeover in the properties of these films in a narrow potential range. Control of the compositional variation of the changeover is dependent on the K+ stoichiometric number in the compound structure. However, a specific K+ occupation in the compound structure activates the occupation of the (H2O)(6) cluster by H3O+ and/or H+, causing the changeover in the properties of hexacyanoferrate film. Thus, the information thus obtained is very useful for understanding the mechanisms involved in the electrochemical reversible switch between ferrimagnetism/paramagnetism, semiconductor/metal and electroluminescence/nonelectroluminescence properties of molecular cyanide materials.