Charge transport of indigo-carmine doped polypyrrole

Charge transport in polypyrrole doped with indigo-carmine was investigated by the method of electrochemical alternating current impedance. By the nonlinear least square fitting, the equivalent circuit and parameter of each component are obtained. The apparent diffusion coefficients and heterogeneous electron transfer constants are given. It is found that, along with the increasing of film thickness, D-app and k(0) increase also.

INDIGO-CARMINE-MODIFIED POLYPYRROLE FILM ELECTRODE

Functionalized polypyrrole films were prepared electrochemically in the presence of indigo-carmine from aqueous solution. The film shows a couple of reversible redox peaks superimposed on a large background of polypyrrole. The redox reaction is pH dependent. The film has good stability in air and can be cycled between -0.1 and 0.4 V (Ag/AgCl) for several hours without any significant changes in the voltammograms. UV-visible spectra indicate the incorporation of indigo-carmine into the polymer matrix.

Influence of particle size on the photoactivity of Ti/TiO2 thin film electrodes, and enhanced photoelectrocatalytic degradation of indigo carmine dye

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Exploratory study on sequestration of some essential metals by indigo carmine food dye

Indigo carmine forms a stable complex with different ions, and the stability constant of the complexes were evaluated as log K equal to 5.75; 5.00; 4.89 and 3.89 for complexes with Cu(II), Ni(II), Co(II) and Zn(II) ions, respectively, in 0.1 mol L -1 carbonate buffer solution at pH 10. The interaction between Cu(II) ions and indigo carmine (IC) in alkaline medium resulted in the formation of the Cu 2(IC) complex, measured by the spectrophotometric method, with a stoichiometric ratio between indigo carmine and metal ions of 2:1 (metal-ligand). The reported method has also been successfully tested for determination of copper in pharmaceutical compounds based on copper-gluconate without pre-treatment.

The mechanism of bacterial indigo reduction

The reduction of water-insoluble indigo by the recently isolated moderate thermophile, Clostridium isatidis, has been studied with the aim of developing a sustainable technology for industrial indigo reduction. The ability to reduce indigo was not shared with C. aurantibutyricum, C. celatum and C. papyrosolvens, but C. papyrosolvens could reduce indigo carmine (5,5-indigosulfonic acid), a soluble indigo derivative. The supernatant from cultures of C. isatidis, but not from cultures of the other bacteria tested, decreased indigo particle size to one-tenth diameter. Addition of madder powder, anthraquinone-2,6-disulfonic acid, and humic acid all stimulated indigo reduction by C. isatidis. Redox potentials of cultures of C. isatidis were about 100 mV more negative than those of C. aurantibutyricum, C. celatum and C. papyrosolvens, and reached –600 mV versus the SCE in the presence of indigo, but potentials were not consistently affected by the addition of the quinone compounds, which probably act by modifying the surface of the bacteria or indigo particles. It is concluded that C. isatidis can reduce indigo because (1) it produces an extracellular factor that decreases indigo particle size, and (2) it generates a sufficiently reducing potential.

On the application of nanostructured electrodes prepared by Ti/TiO2/WO3 template : A case study of removing toxicity of indigo using visible irradiation

New assays with HepG2 cells indicate that Indigo Carmine (IC), a dye that is widely used as additive in many food and pharmaceutical industries exhibited cytotoxic effects. This work describes the development of a bicomponent nanostructured Ti/TiO2/WO3 electrode prepared by template method and investigates its efficiency in a photoelectrocatalytic method by using visible light irradiation and applied potential of 1V. After 2h of treatment there are reduction of 97% discoloration, 62% of mineralization and formation of three byproducts assigned as: 2-amine-5-sulfo-benzoic acid, 2,3-dioxo-14-indole-5-sulfonic acid, and 2-amino-α-oxo-5-sulfo-benzeneacetic acid were identified by HPLC-MS/MS. But, cytotoxicity was completely removed after 120min of treatment. © 2013 Elsevier Ltd.

Investigation of dye functional group on the photocatalytic degradation of dyes by nano-TiO2

The photocatalytic degradation of five anionic, eight cationic and three solvent dyes using combustion-synthesized nano-TiO2 (CSTiO2) and commercial Degussa P-25 TiO2 (DP-25) were evaluated to determine the effect of the functional group in the dye. The degradation of the dyes was quantified using the initial rate of decolorization and mineralization. The decolorization of the anionic dyes with CSTiO2 followed the order: indigo carmine > eosin Y > amido black 10B > alizarin cyanine green > orange G. The decolorization of the cationic dyes with DP-25 followed the order: malachite green > pyronin Y > rhodamine 6G > azure B > nile blue sulfate > auramine O approximate to acriflavine P approximate to safranin O. CSTiO2 showed higher rates of decolorization and mineralization for all the anionic dyes compared to DP-25, while DP-25 was better in terms of decolorization for most of the cationic dyes. The solvent dyes exhibited adsorption dependent decolorization. The order of decolorization and mineralization of the anionic and cationic dyes (a) with CS TiO2 and DP-25 was different and correlated with the surface properties of these catalysts (b) were rationalized with the molecular structure of the dye and the degradation pathway of the dye. (C) 2009 Elsevier B.V. All rights reserved.

Visible light assisted photocatalytic degradation of organic dyes on TiO2-CNT nanocomposites

Carbon nanotubes (CNTs) uniformly decorated with nano-anatase TiO2 particles corresponding to different TiO2-CNT weight ratios (up to 90 % TiO2:10 % CNT) were prepared by employing sol-gel process. The nanocomposites were characterized by X-ray diffraction, IR, Raman, Scanning electron microscopy, Transmission electron microscopy, Photoluminescence, BET surface area and diffuse reflectance measurements. The composites show visible light assisted photocatalytic property, for example, the 90 % TiO2-10 % CNT composite completely degrades Indigo Carmine dye within 1 h of exposure to visible light. Similarly, Orange G and Congo Red dyes were decomposed within 2 h under visible light irradiation. The excellent visible light photocatalytic property of the composite is attributed to the synergetic effect of photoexcitation and photosensitization. This is due to the special nanoarchitecture wherein TiO2 nanoparticles are anchored to CNT surface that provides high specific interfacial area for photon absorption and electron trapping. Visible light assisted degradation profile of Indigo Carmine in the presence of TiO2-CNT nanocomposite and TEM image of the TiO2-CNT nanocomposite.

Total colonic dye-spray increases the detection of diminutive adenomas during routine colonoscopy:a randomized controlled trial

Background: Small adenomas may be missed during colonoscopy, but chromoscopy has been reported to enhance detection. The aim of this randomized-controlled trial was to determine the effect of total colonic dye spray on adenoma detection during routine colonoscopy.

Methods: Consecutive outpatients undergoing routine colonoscopy were randomized to a dye-spray group (0.1% indigo carmine used to coat the entire colon during withdrawal from the cecum) or control group (no dye).

Results: Two hundred fifty-nine patients were randomized, 124 to the dye-spray and 135 to the control group; demographics, indication for colonoscopy, and quality of the preparation were similar between the groups. Extubation from the cecum took a median of 9:05 minutes (range: 2:4824:44 min) in the dye-spray group versus 4:52 minutes (range: 1:42-15:21 min] in the control group (p <0.0001). The proportion of patients with at least 1 adenoma and the total number of adenomas were not different between groups. However, in the dye-spray group significantly more diminutive adenomas (

Conclusions: Dye-spray increases the detection of small adenomas in the proximal colon and patients with multiple adenomas, but long-term outcomes should be studied to determine the clinical value of these findings.

Heterogeneous photocatalytic degradation of acid dyes in aqueous TiO2 suspensions: Kinetics and toxicity

This work assesses the photocatalytic (TiO2/UV) degradation of a simulated acid dye bath (Yellow 3, Red 51, Blue 74, and auxiliary chemicals). Color and phytotoxicity removal were monitored by spectrophotometry and lettuce (Lactuca sativa) seeds as the test organism, respectively. Mineralization was determined by DOC analyses. Photocatalytic, photolytic, and adsorption experiments were performed, showing that adsorption was negligible. After 240 minutes of irradiation, it was achieved 96% and 78% of color removal with photocatalysis and photolysis, respectively. 37% of mineralization occurred with photocatalysis only. The dye bath was rendered completely non-toxic after 60 minutes of photocatalytic treatment; the same result was only achieved with photolysis after 90 minutes. A kinetic model composed of two first-order in series reactions was used. The first photocatalytic decolorization rate constant was k(1) = 0.062 min(-1) and the second k(2) = 0.0043 min(-1), approximately two times greater than the photolytic ones.

Short-term heating tests on doped polypyrrole-coated polyester fabrics

Polyethyleneterephtalate–polypyrrole (PET–PPy) textile complexes incorporating different anionic dopants have been heat treated at 60 °C, 80 °C, 105 °C, 125 °C and 150 °C to investigate effects of short-term heating on conductivity and stability. In most cases heat treatments below 80 °C did not significantly change the final resistance of the conducting textiles. Only the anionic dye-dopant Indigo Carmine acted in a heat-stabilizing manner during treatment at 150 °C, while all samples containing other anionic dopant underwent some degradation. A treatment temperature of 125 °C was the most effective for lowering the final resistance, with sulphonic group containing dopants being particularly effective in improving conductivity and stability. A 29% decrease in the final resistance of a PET–PPy/para-toluene-2-sulphonic acid (pTSA) sample was achievable after 900 s at 125 °C.

Eletroanálise de corantes alimentícios: determinação de índigo carmim e tartrazina

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Avaliação da performance de eletrodos de filmes finos de Ti/TiO 2 com diferentes tamanhos de nanopartículas na oxidação fotoeletrocatalítica de Índigo Carmim

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)