- Rapid and direct spectrophotometric method for kinetics studies and routine assay of peroxidase based on aniline diazo substrates
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Peroxidases are ubiquitous enzymes that play an important role in living organisms. Current spectrophotometrically based peroxidase assay methods are based on the production of chromophoric substances at the end of the enzymatic reaction. The ambiguity regarding the formation and identity of the final chromophoric product and its possible reactions with other molecules have raised concerns about the accuracy of these methods. This can be of serious concern in inhibition studies. A novel spectrophotometric assay for peroxidase, based on direct measurement of a soluble aniline diazo substrate, is introduced. In addition to the routine assays, this method can be used in comprehensive kinetics studies. 4-[(4-Sulfophenyl)azo]aniline (λ max = 390 nm, ? = 32 880 M?1 cm?1 at pH 4.5 to 9) was introduced for routine assay of peroxidase. This compound is commercially available and is indexed as a food dye. Using this method, a detection limit of 0.05 nmol mL?1 was achieved for peroxidase.
- Mirazizi, Fatemeh,Bahrami, Azita,Haghbeen, Kamahldin,Shahbani Zahiri, Hossein,Bakavoli, Mehdi,Legge, Raymond L.
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- Hierarchical construction of SHG-active polar crystals by using multi-component crystals
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Organic salts composed of chiral amines and sulfonic acid with high hyperpolarizability allowed the construction of polar crystals with incorporated guest molecules. The polarity of the crystals was precisely regulated by employing suitable guest molecules. As a result, the crystals generated a strong second harmonic generation property.
- Miyano, Tetsuya,Sakai, Tatsuya,Hisaki, Ichiro,Ichida, Hideki,Kanematsu, Yasuo,Tohnai, Norimitsu
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- The mechanism of sonophotocatalytic degradation of methyl orange and its products in aqueous solutions
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In this study, it was found that a hybrid technique, sonophotocatalysis, is able to degrade a parent organic pollutant (methyl orange) as well as its by-products. The analysis of products formed during the whole degradation has demonstrated that the pH or the selection of oxidation process (sonolysis/photocatalysis/sonophotocatalysis) is able to control the degradation pathway. It was shown in the by-products analysis that the solution pH can alter the amount of each product generated during the sonophotocatalytic degradation. It was revealed that the different degradation rates of methyl orange and its products result from the solution pH and the nature of the organic products. Furthermore, a comparison of the data obtained from the oxidation processes on the degradation of the reaction intermediates identified the advantages of the combined system. It is concluded that sonophotocatalysis is capable of yielding a more complete and faster mineralization of organic pollutants than the individual processes. However, as in the degradation of the parent compound, the overall mineralization is lower than an additive effect (negative synergistic effect).
- He, Yuanhua,Grieser, Franz,Ashokkumar, Muthupandian
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- Visible light photo-oxidation of model pollutants using CaCu 3Ti4O12: An experimental and theoretical study of optical properties, electronic structure, and selectivity
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Charge transfer between metal ions occupying distinct crystallographic sublattices in an ordered material is a strategy to confer visible light absorption on complex oxides to generate potentially catalytically active electron and hole charge carriers. CaCu3Ti4O12 has distinct octahedral Ti4+ and square planar Cu2+ sites and is thus a candidate material for this approach. The sol-gel synthesis of high surface area CaCu3Ti4012 and investigation of its optical absorption and photocatalytic reactivity with model pollutants are reported. Two gaps of 2.21 and 1.39 eV are observed in the visible region. These absorptions are explained by LSDA+U electronic structure calculations, including electron correlation on the Cu sites, as arising from transitions from a Cu-hybridized O 2p-derived valence band to localized empty states on Cu (attributed to the isolation of CuO4 units within the structure of CaCu3Ti4O12) and to a Ti-based conduction band. The resulting charge carriers produce selective visible light photodegradation of 4-chlorophenol (monitored by mass spectrometry) by Pt-loaded CaCu 3Ti4O12 which is attributed to the chemical nature of the photogenerated charge carriers and has a quantum yield comparable with commercial visible light photocatalysts.
- Clark, Joanna H.,Dyer, Matthew S.,Palgrave, Robert G.,Ireland, Christopher P.,Darwent, James R.,Claridge, John B.,Rosseinsky, Matthew J.
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supporting information; experimental part
p. 1016 - 1032
(2011/04/15)
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- Preparation of aminoazo dyes
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Aminoazo dyes are prepared from the corresponding N-sulfomethylated aminoazo dyes by aqueous acid hydrolysis in the presence of amidosulfuric acid, urea or mixtures thereof.
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- Chromium complex compound
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A chromium complex compound represented as the free acid form by the formula (I): STR1 wherein X1 represents a hydrogen atom, a methyl group, a methoxy group or a sulfonic acid group; X2, X3 and X4 represent independently a hydrogen atom, a chlorine atom, a methyl gorup, a methoxy group, a carboxyl group or a sulfonic acid group; Y represents a hydrogen atom or a sulfonic acid group; Z represents a chlorine atom, a fluorine atom or --N30 (R)3 (R represents a C1 to C4 -alkyl group), STR2 and M represents a hydrogen atom or an alkali metal, a process for producing the chromium complex compound (I) and a method for dyeing cellulosic fibers with the same. The chromium complex compound represented by formula (I) is excellent in affinity to cellulosic fibers and in color-yield, build-up properties and fastness properties. These compounds are dyes for cellulosic fibers.
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- Process for the selective destruction, by reduction, of p-coupled products of the 1-naphthol series
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Para-coupled products of the 1-naphthol series can be destroyed in the presence of the ortho-coupled product by reduction with salts of dithionous acid or of hydroxymethanesulphinic acid or with hydrazine optionally in the presence of redox-catalysts.
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- Concentrated direct dye solution and process therefor
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A concentrated dye solution comprising the direct red dye: STR1 where Me is an alkali metal and R is hydrogen, methyl or ethyl ater and urea; and a method for its preparation in situ by a defined sequence of process steps are disclosed.
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