Measurement methods hydrogen peroxide

Color measurement of ozone in terms of oxidation of phenolphthalin (C2oHie04) to phenolphthalein (C20H14O4). In this method hydrogen peroxide is used to develop a standard curve 29, 34)-... 

Wang et al used HRP entrapped into hybrid PVA/silica sol for the measurement of hydrogen peroxide. Their biosensor demonstrated a linear range in the concentrations 0.2-3.4 mM (curve at 3.4 mM in Fig. 4), with detection limit of 5 x 10 M. Furthermore, this biosensor exhibited high sensitivity (15 pA mM ) and fast response time (10 sec.). The results that were calculated from the calibration curve were in close agreement with the ones measured by a standard spectrophotometric method (Table 4). 

Sies, H., 1981. Measurement of hydrogen peroxide formation in situ. Methods Enzymol. 77, 15-20. 

The measurement of hydrogen peroxide within slurries is often done with redox titration methods (manual or automated). Numerous commercial automated titration... 

Photons with maximal intensity at 430 nm are produced. However, the photon efficiency is only 1% and the method is capable of assa ng 1 pg of hydrogen peroxide or 0,1 pg of peroxidase per ml solution. The stem lends itself to measurement of hydrogen peroxide produced by specific enayme methods from such substrates as glucose or urate. Additionally, luminol has been much used as a marker in luminescent Immunoassays. 

Pfister C, Bennett N, Bruckert F, Catty P, Clerc A, Pages F, Deterre P (1993) Interactions of a G-protein with its effector transducin and cGMP phosphodiesterase in retinal rods. Cell Signal 5 235-241 Pick E, Keisari Y (1980) A simple colorimetric method for the measurement of hydrogen peroxide produced by cells in culture. J Immunol Methods 38 161-170... 

The earliest examples of analytical methods based on chemical kinetics, which date from the late nineteenth century, took advantage of the catalytic activity of enzymes. Typically, the enzyme was added to a solution containing a suitable substrate, and the reaction between the two was monitored for a fixed time. The enzyme s activity was determined by measuring the amount of substrate that had reacted. Enzymes also were used in procedures for the quantitative analysis of hydrogen peroxide and carbohydrates. The application of catalytic reactions continued in the first half of the twentieth century, and developments included the use of nonenzymatic catalysts, noncatalytic reactions, and differences in reaction rates when analyzing samples with several analytes. 

Luminol chemiluminescence has also been recommended for measuring bacteria populations (304,305). The luminol—hydrogen peroxide reaction is catalyzed by the iron porphyrins contained in bacteria, and the light intensity is proportional to the bacterial concentration. The method is rapid, especially compared to the two-day period required by the microbiological plate-count method, and it correlates weU with the latter when used to determine bacteria... 

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). 

This is typically accompHshed by cooling the titration solution with ice, determining the blank, and titrating rapidly. Another method utilizes deterrnination of the total peroxide and peracid content by use of a ceric sulfate titration to measure hydrogen peroxide followed by a iodide/thiosulfate titration to measure total active oxygen (60). 

Sulfur Dioxide EPA Method 6 is the reference method for determining emissions of sulfur dioxide (SO9) from stationary sources. As the gas goes through the sampling apparatus (see Fig. 25-33), the sulfuric acid mist and sulfur trioxide are removed, the SO9 is removed by a chemical reaction with a hydrogen peroxide solution, and, finally, the sample gas volume is measured. Upon completion of the rim, the sulfuric acid mist and sulfur trioxide are discarded, and the collected material containing the SO9 is recovered for analysis at the laboratory. The concentration of SO9 in the sample is determined by a titration method. 

A method of detecting herbicides is proposed the photosynthetic herbicides act by binding to Photosystem II (PS II), a multiunit chlorophyll-protein complex which plays a vital role in photosynthesis. The inhibition of PS II causes a reduced photoinduced production of hydrogen peroxide, which can be measured by a chemiluminescence reaction with luminol and the enzyme horseradish peroxidase (HRP). The sensing device proposed combines the production and detection of hydrogen peroxide in a single flow assay by combining all the individual steps in a compact, portable device that utilises micro-fluidic components. 

Quantitative tests for catalase activity find their greatest usefulness in examination of finished product. For this purpose gasometric methods (36) or chemical methods based upon measurement of residual hydrogen peroxide (2) may be used. In the use of these quantitative methods it might be well to observe the precaution of removing the skins. 

This discussion of the structures of diene polymers would be incomplete without reference to the important contributions which have accrued from applications of the ozone degradation method. An important feature of the structure which lies beyond the province of spectral measurements, namely, the orientation of successive units in the chain, is amenable to elucidation by identification of the products of ozone cleavage. The early experiments of Harries on the determination of the structures of natural rubber, gutta-percha, and synthetic diene polymers through the use of this method are classics in polymer structure determination. On hydrolysis of the ozonide of natural rubber, perferably in the presence of hydrogen peroxide, carbon atoms which were doubly bonded prior to formation of the ozonide... 

Olas and Wachowicz (2002) investigated the effects of tranx-resveratrol and vitamin C on oxidative stress in blood platelets. The level of 02 in control blood platelets and platelets incubated with resveratrol or vitamin C was recorded using a chemiluminescence method. On the other hand, Oh and others (2006) reported the x02 quenching activities of various freshly squeezed fruit and vegetable juices by measuring their inhibitory effects on the rubrene oxidation induced by x02 from disproportionation of hydrogen peroxide by sodium molybdate in a microemulsion system. 

Based on the analytical figures of merit of the methods in Table 1, the best precision and selectivity are accomplished by using the decay rate rather than the formation rate or conventional CL-measured parameters such as the peak height or area under the CL curve. Table 2 gives the selectivity factor, expressed as decay-rate and peak-height tolerated concentration ratio, for the CL determination of hydrogen peroxide using SF-CLS. As can be seen, the selectivity factor was quite favorable in most instances. 

Table 2 Selectivity of Various Measurement Methods Used in the Determination of 20 ng/mL Hydrogen Peroxide...

The interatomic distances in peroxyl radicals were calculated by quantum-chemical methods. The experimental measurements were performed only for the hydroperoxyl radical and the calculated values were close to the experimental measurements (see Table 2.5). The length of the O—O bond in the peroxyl radical lies between that in the dioxygen molecule (r0—o= 1.20 x 10-10m) and in hydrogen peroxide (r0—o= 1-45 x 10-lom). 

The formation of radicals from hydrogen peroxide in cyclohexanol was measured by the free radical acceptor method [60] the effective rate constant of initiation was found to be equal to ki = 9.0 x 106 exp(—90.3/RT) s 1. For the first-order decomposition of H2O2 in an alcohol medium, the following reactions were discussed. 

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,... 

The efficiency of superoxide assays strongly depend on the nature of superoxide producers. Significant difficulties arise in the detection of superoxide in cells and tissue. Cytochrome c is unable to penetrate cell membranes and therefore, can be used only for the measurement of extracellular superoxide. Furthermore, SOD-inhibitable cytochrome c reduction is difficult to apply in nonphagocytic cells and tissue due to the complications of measuring low rates of superoxide release, direct reduction of cytochrome c by cellular enzymes, the reoxidation of reduced cytochrome by hydrogen peroxide, etc. [8], Moreover, in nonphagocytic cells superoxide is formed exclusively inside the cells and is not released outside as in phagocytes. These circumstances severely limit the number of analytical methods, which can be used for superoxide detection in vasculature. 

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