Hydrogen peroxide estimation

Acid Solution. Acetone and hydrogen peroxide are the principal oxidation products observed in the radiolysis of 2-propanol in sulfuric acid solution. Identical results were obtained for hydrogen peroxide estimation by both the titanium sulfate and iodide ion estimations, indicating that organic hydroperoxides were not formed or that, if formed, they rapidly decompose to acetone and hydrogen peroxide. The yields obtained are summarized in Table I. In all cases, it was clearly established that product yields were independent of dose initially. 

Misra, N., Biswal, J., Gupta, A., Sainis, J. K., and Sabharwal, S. 2012. Gamma radiation induced synthesis of gold nanoparticles in aqueous polyvinyl pyrrolidone solution and its application for hydrogen peroxide estimation. Radiat. Phys. Chem. 81(2) 195-200. 

The reaction with acidified potassium manganate(VII) is used in the quantitative estimation of hydrogen peroxide. 

The Reich test is used to estimate sulfur dioxide content of a gas by measuring the volume of gas required to decolorize a standard iodine solution (274). Equipment has been developed commercially for continuous monitoring of stack gas by measuring the near-ultraviolet absorption bands of sulfur dioxide (275—277). The deterrnination of sulfur dioxide in food is conducted by distilling the sulfur dioxide from the acidulated sample into a solution of hydrogen peroxide, foUowed by acidimetric titration of the sulfuric acid thus produced (278). Analytical methods for sulfur dioxide have been reviewed (279). 

The most characteristic property of the oxaziranes is tlieir strong oxidizing character which is approximately equal to that of hydrogen peroxide. Oxaziranes react with hydrochloric acid the chlorine thus liberated is, however, used up in secondary reactions. " Two equivalents of iodine are formed from acid iodide solutions according to Eq. Titration of the free iodine allows a simple estimation of... 

Fig. 14.13 (a) Bubble temperatures estimated using the MRR method as a function of thermal conductivity for the rare gases, (b) Hydrogen peroxide concentration following sonication of pure water as a function of gas solubility in different rare gases ( ) He ( ) Ne (a) Ar ( ) Kr ( ) Xe ( ) He/Xe mixture [42] (reprinted with permission from the American Chemical Society)... 

XOD is one of the most complex flavoproteins and is composed of two identical and catalytically independent subunits each subunit contains one molybdenium center, two iron sulfur centers, and flavine adenine dinucleotide. The enzyme activity is due to a complicated interaction of FAD, molybdenium, iron, and labile sulfur moieties at or near the active site [260], It can be used to detect xanthine and hypoxanthine by immobilizing xanthine oxidase on a glassy carbon paste electrode [261], The elements are based on the chronoamperometric monitoring of the current that occurs due to the oxidation of the hydrogen peroxide which liberates during the enzymatic reaction. The biosensor showed linear dependence in the concentration range between 5.0 X 10 7 and 4.0 X 10-5M for xanthine and 2.0 X 10 5 and 8.0 X 10 5M for hypoxanthine, respectively. The detection limit values were estimated as 1.0 X 10 7 M for xanthine and 5.3 X 10-6M for hypoxanthine, respectively. Li used DNA to embed xanthine oxidase and obtained the electrochemical response of FAD and molybdenum center of xanthine oxidase [262], Moreover, the enzyme keeps its native catalytic activity to hypoxanthine in the DNA film. So the biosensor for hypoxanthine can be based on... 

Dilling, W.L., Gonsior, S.J., Boggs, G.U., Mendoza, C.G. (1988) Organic photochemistry. 20. A method for estimating gas-phase rate for reactions of hydroxyl radicals with organic compounds from their relative rates of reaction with hydrogen peroxide under photolysis in 1,1,2-trichlorotrifluoroethane solution. Environ. Sci. Technol. 22, 1447-1453. 

In earlier studies [5,6] superoxide detection in mitochondria was equated to hydrogen peroxide formation. However, while it is quite possible that superoxide is a stoichiometric precursor of mitochondrial hydrogen peroxide, it is understandable that the level of hydrogen peroxide may be decreased due to the reactions with various mitochondrial oxidants. Moreover, superoxide level can be underestimated due to the reaction with mitochondrial MnSOD. Several authors [7,8] assumed that mitochondrial superoxide production may be estimated through cyanide-resistant respiration, which supposedly characterizes univalent dioxygen reduction. This method was applied for the measurement of superoxide production under in vitro normoxic and hyperoxic conditions, in spite of the finding [7] that cyanide-resistant respiration reflects also the oxidation of various substrates (lipids, amino acids, and nucleotides). Earlier,... 

Skin-Contact Toxicity Data for acute (short-term) exposures of the skin to corrosive and toxic liquids, solids, and gases are extremely limited, particularly where the consequences are severe or fatal injury and the available data may not be useful, from an engineering standpoint. For example, the skin toxicity of hydrogen peroxide to rats is stated as 4060 mg/kg, but the skin area and duration of exposure are not stated. Thus, it is not possible (with the available data) to estimate the relationship among percent of body surface exposed to a corrosive material, the concentration of the corrosive material, the duration of exposure (before removal of the corrosive material), and the severity of the effect. 

Working capital estimates, 9 530-531 Working electrodes, 9 568-571, 585 Working fluids, heat pipe, 13 230-233 Working Party of Experts on the Official Control of Pesticides, 18 541 Working solution, 14 43, 44 composition of, 14 46-47 hydrogen peroxide recovery from,... 

Neutron activation analysis has been used to determine selenium in soil [144-148], Nadkarni and Morrison [149] estimated 47 elements in lake sediments and found 0.3-1.01pg selenium per gram using neutron activation analysis. Dong et al. [162] used mixtures of phosphoric acid, nitric acid and hydrogen peroxide in the digestion of soils prior to the determination of selenium. 

Hydrogen peroxide solution and potassium bromide are two pharmaceutical substances that may be estimated by employing 0.1 N potassium permanganate solution and adopting the direct titration method. 

Thioetherification of PECH is feasibly performed in DA-solvents as already described in the patent (20J. For example, the highest substitution was obtained by the reaction of P(ECH-EO)(1 1 copolymer of epichloro-hydrin and ethylene oxide) and equimolar thiophenoxide in HMPA at 100°C for 10 h as DS 83% for sodium and 93% for potassium salts. The DS in our nucleophilic substitution was estimated by the elemental analysis as well as the titration of liberated chloride ion with mercuric nitrate (21). In the latter method, reacted medium was pretreated with hydrogen peroxide when the reductive nucleophiles which can react with mercuric ion were used. As described before for PVC, thiolation was also achieved conveniently with iso-thiuronium salt followed by alkaline hydrolysis without the direct use of ill-smelling thiolate. The thiolated PECH obtained are rubbery solids, soluble in toluene, methylene chloride, ethyl methyl ketone and DMF and insoluble in water, acetone, dioxane and methanol. 

The authors report detection limits of 8x10 ° mol/dm for TATP and 8 X lO mol/dm for HMTD. When p-hydroxyphenylacetic acid (p-HPAA) (6) was used as the oxidation substrate instead of ABTS, a highly fluorescent dimer (7) was formed. This dimer could be detected spectrophotometricaUy, although the sensitivity dropped (Eq. (12)). Both methods also enabled a semi-quantitative estimation of TATP and HMTD concentrations [86]. Dimerization of p-hydroxyphenylacetic acid (p-HPAA) by hydrogen peroxide in presence of peroxidase [86] is as foUows ... 

---