Characterization of a titanium(IV)–porphyrin complex as a highly sensitive and selective reagent for the determination of hydrogen peroxide: a computational chemistry approach and a critical review

The Ti–TPyP reagent, i.e. an acidic aqueous solution of the oxo[5,10,15,20-tetra(4-pyridyl)porphyrinato] titanium(IV) complex, TiO(tpyp), was developed as a highly sensitive and selective spectrophotometric reagent for determination of traces of hydrogen peroxide. Using this reagent, determination of hydrogen peroxide was performed by flow-injection analysis with a detection limit of 0.5 pmol per test. The method was actually applied to determination of several constituents of foods, human blood, and urine mediated by appropriate oxidase enzymes. The reaction specificity of the TiO(tpyp) complex for hydrogen peroxide was clarified from the viewpoint of the reaction mechanisms and molecular orbitals based on ab initio calculations. The results provided a well-grounded argument for determination of hydrogen peroxide using the Ti–TPyP reagent experimentally. This review deals with characterization of the high sensitivity and reaction specificity of the Ti–TPyP reagent for determination of hydrogen peroxide, to prove its reliability in analytical applications. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

Photometric and Gas-Chromatographic Determination of Hydrogen Peroxide and Peroxybutanoic Acid in Oxidized Butanoic Acid

Procedures were developed for determining hydrogen peroxide and peroxy acids mixed with peroxide compounds of other classes in the oxidation products of butanoic acid with atmospheric oxygen and hydrogen peroxide. Conditions were found for the selective decomposition of hydrogen peroxide with catalase in the presence of an excess of the carboxylic acid deactivating the enzyme. The errors introduced by the acylation of hydrogen peroxide with the carboxylic acid in the course of sample treatment with the enzyme were eliminated by adding diphenyl sulfide or dimethyl sulfoxide, which selectively reduced the peroxy acids. The concentrations of hydrogen peroxide and the peroxy acid were found from the difference between the total concentration of the peroxide compounds before and after treating a sample with catalase and a sulfur-containing reagent by the photometric method using a reagent containing Fe²⁺ ions and N, N-dimethyl-p-phenylenediamine. Peroxy acids were determined by GLC from the yields of the oxidation products of diphenyl sulfide with the peroxy acid (diphenyl sulfoxide and diphenyl sulfones).     

Use of the vanadium(V)-xylenol orange mixture as an improved reagent for the spectrophotometric determination of traces of hydrogen peroxide

The reaction in V(V)-xylenol orange (XO)-H₂O₂ system was studied by spectrometry. On the addition of hydrogen peroxide to the mixture of vanadium(V) and XO (V-XO reagent), the absorption peak of V(V)-XO complex (λ_max = 582 nm) decreased significantly. The decrease in the absorbance (denoted as ΔA) was proportional to the concentration of hydrogen peroxide. The constant values of ΔA were obtained under the condition of [XO]/[V(V)] = 0.5 ~ 1.2 and in the pH 3.5 ~ 4.5 region. Based on these results, the conditions for the use of the V-XO reagent in the colorimetric determination of hydrogen peroxide were examined in detail. The V-XO reagent was found to be useful for the trace analysis of hydrogen peroxide with high sensitivity, and the data were little affected by the presence of some inorganic and organic substances. The lower limit of the determination is about 1 × 10^?6M.     

A Novel Fluorescent Reagent for Analysis of Hydrogen Peroxide

IntroductionTheoxidationofmanyclinicalsubstancesinbodyfluidsproducesaquantityofhydrogenperoxide ,sothedetermina tionoftracehydrogenperoxideisofconsiderableimportanceinclinicalchemistry .1Further,themonitoringofhydrogenperoxideisalsonecessarytoenvironmentalsciencesinceitisakeyspeciesinthereactionsofthetroposphere,beingin volvedinimportantreactionssuchasthecatalyzedoruncat alyzedaqueousphaseoxidationofSO2 andtheultraviolet en hancedaqueousphaseoxidationoforganicspecies.2 Uptonow ,variousmethods…     

Direct electrochemistry and electrochemical catalysis of myoglobin-TiO2 coated multiwalled carbon nanotubes modified electrode

TiO(2) nanoparticles were homogeneously coated on multiwalled carbon nanotubes (MWCNTs) by hydrothermal deposition, and this nanocomposite might be a promising material for myoglobin (Mb) immobilization in view of its high biocompatibility and large surface. The glassy carbon (GC) electrode modified with Mb-TiO(2)/MWCNTs films exhibited a pair of well-defined, stable and nearly reversible cycle voltammetric peaks. The formal potential of Mb in TiO(2)/MWCNTs film was linearly varied in the range of pH 3-10 with a slope of 48.65 mV/pH, indicating that the electron transfer was accompanied by single proton transportation. The electron transfer between Mb and electrode surface, k(s) of 3.08 s(-1), was greatly facilitated in the TiO(2)/MWCNTs film. The electrocatalytic reductions of hydrogen peroxide were also studied, and the apparent Michaelis-Menten constant is calculated to be 83.10 microM, which shows a large catalytic activity of Mb in the TiO(2)/MWCNTs film to H(2)O(2). The modified GC electrode shows good analytical performance for amperometric determination of hydrogen peroxide. The resultant Mb-TiO(2)/MWCNTs modified glassy carbon electrode exhibited fast amperometric response to hydrogen peroxide reduction, long term life and excellent stability. Finally the activity of the sensor for nitric oxide reduction was also investigated.     

Kinetic studies on the reaction of N-(2-hydroxyethyl)ethylenediamine-N,N′,N′-triacetate chromium(III) with hydrogen peroxide

The rate of reaction of Cr(III)L (L=N-(2-hydroxyethyl)ethylenediamine-N,N′,N′-triacetate) with hydrogen peroxide was studied in aqueous media and was found to yield Cr(VI) over the temperature range of 25–41 °C. The reaction was followed spectrophotometrically at 396 nm under pseudo-first order conditions with hydrogen peroxide in a large excess. The reaction follows first-order kinetics in Cr(III). The dependence of the rate constant on hydrogen peroxide concentration is attributed to the formation of an intermediate between the monohydroxy chromium(III) complex and hydrogen peroxide which decomposes in the rate determining step. At high hydrogen peroxide concentration, the order is changed from first to zero order.The values of the intramolecular electron transfer rate constant, the formation constant of the intermediate complex and the activation parameters were calculated.     

Mechanistic studies for modelling the metal ioncatalyzed tiron-hydrogen peroxide indicator reaction

Model building of kinetic-catalytic methods of determination is attempted for the tironhydrogen peroxide indicator reaction catalyzed by cobalt(II) and manganese(II) in alkaline medium. As a first approximation, rate equations for the metal ion-catalyzed reactions are derived from kinetic dependences on reagent concentrations and pH. More general models are obtained by considering the metal ion equilibria in the reaction mixture. For Co(II), a ternary tironhydrogen peroxideCo(II) complex was found to be responsible for the catalytic activity. As stability constants of peroxo (Co(II) complexes are unknown, only a qualitative approach can be given. Manganese catalyzes the indicator reaction in the presence of 1,10-phenanthroline or 2,2′-bipyridine. The initial rates under pseudo zero-order conditions in hydrogen peroxide and tiron correlate directly with the fraction of ternary activatortironMn(II) complex present. For bipyridine as activator, the rate constant is 1.31 × 10⁶ M^?1 min^?1 with respect to the ternary complex.     

Simple and rapid determination of hydrogen peroxide using phosphine-based fluorescent reagents with sodium tungstate dihydrate.

A simple batch method for the fluorometric determination of hydrogen peroxide using phosphine-based fluorescent reagents has been developed. A rapid, mild and selective derivatization reaction was achieved by adding sodium tungstate dihydrate to the reaction mixture of hydrogen peroxide and a phosphine-based fluorescent reagent. When 4-diphenylphosphino-7-methylthio-2,1,3-benzoxadiazole was used as a reagent, the derivatization reaction was completed after 2 min at room temperature. The calibration curve was linear between 12.5 and 500 ng hydrogen peroxide in a 10 microL sample solution. This method is accurate and has potential for on-line applications.     

紫外分光光度法测定聚硫密封胶中二氧化钛

基于强酸性溶液中钛氧离子与H2O2发生显色络合反应的原理,建立了浓硫酸–硫酸铵消解–紫外分光光度法测定聚硫密封胶中TiO_2含量的方法。通过对酸液和显色剂用量,以及显色络合物稳定性的系统考察,确定浓硫酸用量为2 mL,双氧水用量为3 mL,检测波长为403 nm。二氧化钛质量浓度在0~130μg/mL范围内与其吸光度呈良好的线性关系,线性方程为A=5.047 8c–0.019 31,r~2=0.999 2,检出限为0.08μg/mL。检测结果的相对标准偏差为0.89%(n=5),3水平加标平均回收率为101.7%。该方法线性范围较宽、检出限低、重复性好,可用于聚硫密封胶中二氧化钛的定量分析。     

Flocculation-induced homolysis of hydrogen peroxide in aqueous colloid solution of titanium dioxide nanoparticles

Thermal generation of oxygen and hydroxylated aromatic compounds by hydrogen peroxide, catalyzed by flocculation of titanium dioxide nanocrystallites aqueous suspension upon addition of hydrogen peroxide, is reported. The oxidation involves catalytic cleavage of a peroxide molecule followed by hydroxyl reaction with the organic solutes. The catalytic hydroxylation is associated with formation of TiO(2)-H(2)O(2) aggregates, which occurs within a specific range of [TiO(2)]/[H(2)O(2)] ratio. Comparison of the activation energy to literature values in the absence of nanoparticles indicates that flocculation induces an increase of the rate without decreasing the activation energy. This is, to the best of our knowledge, a unique case of nanoparticles catalysis driven by formation of a three-dimensional structure of the suspended particles.     

Chemiluminescent flow-through sensor for 1,10-phenanthroline based on the combination of molecular imprinting and chemiluminescence.

A functional polymer for the catalysis of the chemiluminescent reaction and molecular recognition ability of 1,10-phenanthroline was prepared based on the molecular imprinting method. The structural and catalytic roles of transition metal ion interactions were applied in the material design. A ternary complex, 4-vinylpyridine-Cu(II)-1,10-phenanthroline (2:1:1), was synthesized and used as a functional monomer. The ligand 1,10-phenanthroline in the ternary complex was the template used to form the molecularly imprinted polymer. Another monomer, styrene, and the cross-linking reagent divinylbenzene were copolymerized with the ternary complex. The polymer containing the ternary complex is an efficient catalyst for the decomposition of hydrogen peroxide. During the hydrogen peroxide decomposition, superoxide radical ion is formed, which reacts with 1,10-phenanthroline and gives a chemiluminescent emission. The 1,10-phenanthroline was destroyed during the chemiluminescent reaction, leaving a cavity and copper binding sites for another 1,10-phenanthroline molecule. The prepared polymer particles were packed into a glass tube and developed as a molecular recognition chemiluminescent flow-through sensor for 1,10-phenanthroline. The sensitivity and selectivity of the sensor were tested.     

Removal of Ascorbic Acid Interference in Horseradish Peroxidase Estimations of Hydrogen Peroxide

Abstract

Ascorbic acid, which depresses the colour and interferes in reactions in colorimetric and fluorometric assay procedures for hydrogen peroxide involving horseradish peroxidase, has been removed from solutions by treatment with an iodine reagent. This reagent strongly interferes with procedures involving scopoletin, 2,2′-azinobis-(3-ethylbenzthiazoline-6-sulphonic acid) and the reaction between 3-dimethylaminobenzoic acid and 3-methyl-2-benzothiazolinone hydrazone. The iodine reagent slightly depressed the fluorescence obtained using hydroxyphenylacetic acid but this was the most suitable electron donor for amounts of hydrogen peroxide between 6 and 60 nmol. Hydroxyphenylacetic acid spontaneously reduces residual iodine.     

The analysis of combustion products : Some improvements in the methods of analysis of peroxides

The conditions for the estimation of peroxides by three established, methods have been re-examined in detail. 1. It is shown that the reduction of organic hydroperoxides by stannous chloride (barnard and hargrave method) can be carried out quantitatively and rapidly in alkaline solution. The advantages of this modification are discussed. 2. The exact conditions are described for accurately measuring the concentrations of hydrogen peroxide and of the lower organic peroxides by the thiocyanate method. Amyl alcohol is recommended as a decolourizer for the reagent since the red colour produced by the action of the peroxides is stabilized, permitting accurate spectrophotometric measurements, Using this reagent, 0.03 micrograms of peroxide per ml can be estimated. 3. The limits of the titanous sulphate method of estimating hydrogen peroxide have been determined and a method suitable for the determination of 0.3 micrograms of hydrogen peroxide per ml is described.     

Intensification of electrochemiluminescence of luminol on TiO2 supported Au atomic cluster nano-hybrid modified electrode

With TiO(2) nanoparticles as carrier, a supported nano-material of Au atomic cluster/TiO(2) nano-hybrid was synthesized. It was then modified onto the surface of indium tin oxide (ITO) by Nafion to act as a working electrode for exciting the electrochemiluminescence (ECL) of luminol. The properties of the nano-hybrid and the modified electrode were characterized by XRD, XPS, electronic microscopy, electrochemistry and spectroscopy. The experimental results demonstrated that the modification of this nano-hybrid onto the ITO electrode efficiently intensified the ECL of luminol. It was also revealed that the ECL intensity of luminol on this modified electrode showed very sensitive responses to oxygen and hydrogen peroxide. The detection limits for dissolved oxygen and hydrogen peroxide were 2 μg L(-1) and 5.5 × 10(-12) M, respectively. Besides the discussion of the intensifying mechanism of this nano-hybrid for ECL of luminol, the developed method was also applied for monitoring dissolved oxygen and evaluating the scavenging efficiency of reactive oxygen species of the Ganoderma lucidum spore.     

Catalysis by heteropolyacid—VII. catalytic oxidation of cyclohexanol by dodecamolybdate

In the oxidation of cyclohexanol to cyclohexanone and the further oxidation to adipic acid, a dodecamolybdo-heteropolyanion (HPA) functions catalytically in the presence of aqueous hydrogen peroxide, whereas the HPA without hydrogen peroxide reacts only stoichiometrically. Air- or oxygen-passing through the refluxing system of cyclohexanone and the HPA in the presence of active charcoal, without hydrogen peroxide, has also promoted the oxidation catalytically. Since both hydrogen peroxide and aeration in the presence of active charcoal convert the reduced-form (blue) of the HPA produced by the oxidation of substrate to the oxidized-form (yellow), they play a role as a promoter or a reoxidizing reagent for the oxidation by the HPA. The reoxidizing effect of the aqueous hydrogen peroxide is much the more effective.     

Oxidimetric determination of some compounds with hexamminecobalt(III) tricarbonatocobaltate(III)

The possibilities of utilization of the hexamminecobalt(III) tricarbonatocobaltate(III) complex for potentiometric determination of some substances are discussed. The reaction scheme for this reagent is proposed for acidic media (the “generation” of Co³⁺). A microdetermination of iodide has been developed. The oxidation of thiocyanate, thiosulfate and hydrogen peroxide is briefly discussed.     

Catalytic activity of Cu(II)–poly(vinyl alcohol) complex for decomposition of hydrogen peroxide

Decomposition of hydrogen peroxide was examined was examined by using Cu(II)–poly(vinyl alcohol) (PVA) as catalyst. The rates of decomposition were measured. Electronic spectra and infrared spectra of Cu(II)–PVA complex systems were determined at various stages of decomposition. Effect of addition of various amines to the Cu(II)–PVA system on catalytic action was considered. The relation between the initial rate and the initial concentration of hydrogen peroxide varied in accordance with the rate expression of Michaelis-Menten type. Cu(II)–PVA complex was found to have a large catalytic activity, while the polymeric PVA ligand and copper(II) ion exhibited less activity than Cu(II)–PVA complex. For hydrogen peroxide decomposition, Cu(II)–PVA complex showed catalytic activity when a stable complex of planar structure formed, while many other polymer complexes reported by other authors showed the catalytic activity when they were in unstable complex forms. An amine substituent has a critical influence on the rate of hydrogen peroxide decomposition. The mechanism in the first step of reaction for hydrogen peroxide decomposition is discussed.     

N,N-diethylaniline as hydrogen donor for determination of hydrogen peroxide catalyzed by metalloporphyrins as enzyme mimetic of peroxidase

Various metalloporphyrins have been used as a catalyst instead of the peroxidase for the determination of hydrogen peroxide by formation of a dye from N,N-diethylaniline (DBA) and 4-aminoantipyrine. The difference of relative catalytic activity was investigated between enzyme and enzyme mimetics. FeT(4-TAP)P [5, 10, 15, 20-tetrakis (4-trimethyl-ammoniumphenyl)-21H, 23H-porphine] was shown as the best enzyme mimetic for horseradish peroxidase (HRP) among metalloporphyrins tested. 0 to 7.0 × 10^–5 mol/L hydrogen peroxide was determined with good accuracy and reproducibility, and giving recovery of 99.7–100.7%. DEA was certified as a sensitive color reagent in enzyme mimetic assay of hydrogen peroxide, with the apparent molar absorptivity for hydrogen peroxide was 1.37 × 10⁴ L/mol·cm.     

Supramolecular Assembly of Heterogeneous Multiporphyrin Arrays—Structures of [{ZnII(tpp)}2(tpyp)] and the Coordination Polymer [{[MnIII(tpp)]2(tpyp)(ClO4)2}∞]

Channels make up 46% of the crystal volume: A two-dimensional coordination polymer of exceptional structural regularity (see schematic drawing; tpp=tetraphenylporphyrin, tpyp=tetrapyridylporphyrin) was assembled from [Mn^III(tpp)]⋅ClO₄ and tpyp. The crystal packing of these polymers yields an open bulk structure with networks of perpendicular channels filled with nitrobenzene solvent molecules. Only oligomeric entities are formed by the reaction of [Zn^II(tpp)] with tpyp.     

漂白粉中总钙量测定方法的改进

采用过氧化氢去除漂白粉中的有效氯,直接测定漂白粉中总钙量,探讨过氧化氢用量,反应时间,试剂加入顺序对实验结果的影响。结果表明,当过氧化氢用量为1.5～4.5 mL,反应时间为3 min时,试剂加入顺序为：过氧化氢―氨性缓冲溶液―Mg2＋-EDTA―铬黑T,体系对测定结果影响最小。用该方法测定了漂白粉中总钙量,其相对标准...