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Sample records for hydrogen peroxide catalyzed

  1. Kinetics of Platinum-Catalyzed Decomposition of Hydrogen Peroxide

    NASA Astrophysics Data System (ADS)

    Vetter, Tiffany A.; Colombo, D. Philip, Jr.

    2003-07-01

    CIBA Vision Corporation markets a contact lens cleaning system that consists of an AOSEPT disinfectant solution and an AOSEPT lens cup. The disinfectant is a buffered 3.0% m/v hydrogen peroxide solution and the cup includes a platinum-coated AOSEPT disc. The hydrogen peroxide disinfects by killing bacteria, fungi, and viruses found on the contact lenses. Because the concentration of hydrogen peroxide needed to disinfect is irritating to eyes, the hydrogen peroxide needs to be neutralized, or decomposed, before the contact lenses can be used again. A general chemistry experiment is described where the kinetics of the catalyzed decomposition of the hydrogen peroxide are studied by measuring the amount of oxygen generated as a function of time. The order of the reaction with respect to the hydrogen peroxide, the rate constant, and the energy of activation are determined. The integrated rate law is used to determine the time required to decompose the hydrogen peroxide to a concentration that is safe for eyes.

  2. MEMS-Based Satellite Micropropulsion Via Catalyzed Hydrogen Peroxide Decomposition

    NASA Technical Reports Server (NTRS)

    Hitt, Darren L.; Zakrzwski, Charles M.; Thomas, Michael A.; Bauer, Frank H. (Technical Monitor)

    2001-01-01

    Micro-electromechanical systems (MEMS) techniques offer great potential in satisfying the mission requirements for the next generation of "micro-scale" satellites being designed by NASA and Department of Defense agencies. More commonly referred to as "nanosats", these miniature satellites feature masses in the range of 10-100 kg and therefore have unique propulsion requirements. The propulsion systems must be capable of providing extremely low levels of thrust and impulse while also satisfying stringent demands on size, mass, power consumption and cost. We begin with an overview of micropropulsion requirements and some current MEMS-based strategies being developed to meet these needs. The remainder of the article focuses the progress being made at NASA Goddard Space Flight Center towards the development of a prototype monopropellant MEMS thruster which uses the catalyzed chemical decomposition of high concentration hydrogen peroxide as a propulsion mechanism. The products of decomposition are delivered to a micro-scale converging/diverging supersonic nozzle which produces the thrust vector; the targeted thrust level approximately 500 N with a specific impulse of 140-180 seconds. Macro-scale hydrogen peroxide thrusters have been used for satellite propulsion for decades; however, the implementation of traditional thruster designs on a MEMS scale has uncovered new challenges in fabrication, materials compatibility, and combustion and hydrodynamic modeling. A summary of the achievements of the project to date is given, as is a discussion of remaining challenges and future prospects.

  3. [Oxidative destruction of estradiol after treatment with hydrogen peroxide catalyzed by horseradish peroxidase and methemoglobin].

    PubMed

    Petrenko, Iu M; Matiushin, A I; Titov, V Iu

    1999-01-01

    It is shown that estradiol in the presence of horse radish peroxidase interacts with hydrogen peroxide, which is evidenced by an increase in its optical density at 280 nm. The photometering of samples containing estradiol and horse radish peroxidase upon their titration with hydrogen peroxide indicated that the increase in optical density stops after introducing hydrogen peroxide equimolar in concentration to estradiol. The stoichiometric ratio of estradiol consumed during oxidative destruction to hydrogen peroxide was 1:1. In the presence of ascorbate, the oxidative destruction of estradiol by the action of hydrogen peroxide, catalyzed by horse radish peroxidase, was observed only after a latent period and showed the same regularities as in the absence of ascorbate. It was found by calorimetry that, during the latent period, estradiol catalyzes the degradation of hydrogen peroxide and ascorbate without undergoing oxidative destruction. The substrates of the peroxidase reaction benzidine, 1-naphthol, and phenol interact with hydrogen peroxide in the presence of ascorbate and horse radish peroxidase in a similar way. Presumably, upon interaction with hydrogen peroxide in the presence of horse radish peroxidase, estradiol, like other substrates of this reaction, undergoes oxidative destruction by the mechanism of peroxidase reaction. It is shown that oxidative destruction of estradiol by the action of hydrogen peroxide can also be catalyzed by methemoglobin by the same mechanism. These data are important for understanding the role of estradiol in the organism and the pathways of its metabolic conversions.

  4. An investigation into copper catalyzed D-penicillamine oxidation and subsequent hydrogen peroxide generation.

    PubMed

    Gupte, Anshul; Mumper, Russell J

    2007-04-01

    D-Penicillamine is a potent copper (Cu) chelating agent. D-Pen reduces Cu(II) to Cu(I) in the process of chelation while at the same time being oxidized to D-penicillamine disulfide. It has been proposed that hydrogen peroxide is generated during this process. However, definitive experimental proof that hydrogen peroxide is generated remains lacking. Thus, the major aims of these studies were to confirm and quantitatively assess the in vitro production of hydrogen peroxide during copper catalyzed D-penicillamine oxidation. The potential cytotoxic effect of hydrogen peroxide generation was also investigated in vitro against MCF-7 human breast cancer cells. Cell cytotoxicity resulting from the incubation of D-penicillamine with copper was compared to that of D-penicillamine, copper and hydrogen peroxide. The mechanism of copper catalyzed D-penicillamine oxidation and simultaneous hydrogen peroxide production was investigated as a function of time, concentration of cupric sulfate or ferric chloride, temperature, pH, anaerobic condition and chelators such as ethylenediaminetetraacetic acid and bathocuproinedisulfonic acid. A simple, sensitive and rapid HPLC assay was developed to simultaneously detect D-penicillamine, its major oxidation product D-penicillamine disulfide, and hydrogen peroxide in a single run. Hydrogen peroxide was shown to be generated in a concentration dependent manner as a result of D-penicillamine oxidation in the presence of cupric sulfate. Chelators such as ethylenediaminetetraacetic acid and bathocuproinedisulfonic acid were able to inhibit D-penicillamine oxidation. The incubation of MCF-7 human breast cancer cells with D-penicillamine plus cupric sulfate resulted in the production of reactive oxygen species within the cell and cytotoxicity that was comparable to free hydrogen peroxide.

  5. MINERALIZATION OF A SORBED POLYCYCLIC AROMATIC HYDROCARBON IN TWO SOILS USING CATALYZED HYDROGEN PEROXIDE. (R826163)

    EPA Science Inventory

    Hydrogen peroxide (H2O2) catalyzed by soluble iron or naturally occurring soil minerals, (i.e., modified Fenton's reagent) was investigated as a basis for mineralizing sorbed and NAPL-phase benzo[a]pyrene (BaP), a hydrophobic and toxic polycyclic a...

  6. MINERALIZATION OF A SORBED POLYCYCLIC AROMATIC HYDROCARBON IN TWO SOILS USING CATALYZED HYDROGEN PEROXIDE. (R826163)

    EPA Science Inventory

    Hydrogen peroxide (H2O2) catalyzed by soluble iron or naturally occurring soil minerals, (i.e., modified Fenton's reagent) was investigated as a basis for mineralizing sorbed and NAPL-phase benzo[a]pyrene (BaP), a hydrophobic and toxic polycyclic a...

  7. Oxidation of benzene with hydrogen peroxide catalyzed with ferrocene in the presence of pyrazine carboxylic acid

    NASA Astrophysics Data System (ADS)

    Shul'pina, L. S.; Durova, E. L.; Kozlov, Yu. N.; Kudinov, A. R.; Strelkova, T. V.; Shul'pin, G. B.

    2013-12-01

    It is found that ferrocene in the presence of small amounts of pyrazine carboxylic acid (PCA) effectively catalyzes the oxidation of benzene to phenol with hydrogen peroxide. Two main differences upon the oxidation of two different substrates, i.e., cyclohexane and benzene, with the same H2O2-ferrocene-PCA catalytic system are revealed: the rates of benzene oxidation and hydrogen peroxide decomposition are several times lower than the rate of cyclohexane oxidation at close concentrations of both substrates, and the rate constant ratios for the reactions of oxidizing particles with benzene and acetonitrile are significantly lower than would be expected for reactions involving free hydroxyl radicals. The overall rate of hydrogen peroxide decomposition, including both the catalase and oxidase routes, is lower in the presence of benzene than in the presence of cyclohexane. It is suggested on the grounds of these data that a catalytically active particle different from the one generated in the absence of benzene is formed in the presence of benzene. This particle catalyzes hydrogen peroxide decomposition less efficiently than the initial complex and generates a dissimilar oxidizing particle that exhibits higher selectivity. It is shown that reactivity of the system at higher concentrations of benzene differs from that of an initial system not containing an aromatic component with the capability of π-coordination with metal ions.

  8. Efficient Method for the Determination of the Activation Energy of the Iodide-Catalyzed Decomposition of Hydrogen Peroxide

    ERIC Educational Resources Information Center

    Sweeney, William; Lee, James; Abid, Nauman; DeMeo, Stephen

    2014-01-01

    An experiment is described that determines the activation energy (E[subscript a]) of the iodide-catalyzed decomposition reaction of hydrogen peroxide in a much more efficient manner than previously reported in the literature. Hydrogen peroxide, spontaneously or with a catalyst, decomposes to oxygen and water. Because the decomposition reaction is…

  9. Efficient Method for the Determination of the Activation Energy of the Iodide-Catalyzed Decomposition of Hydrogen Peroxide

    ERIC Educational Resources Information Center

    Sweeney, William; Lee, James; Abid, Nauman; DeMeo, Stephen

    2014-01-01

    An experiment is described that determines the activation energy (E[subscript a]) of the iodide-catalyzed decomposition reaction of hydrogen peroxide in a much more efficient manner than previously reported in the literature. Hydrogen peroxide, spontaneously or with a catalyst, decomposes to oxygen and water. Because the decomposition reaction is…

  10. First-principles simulations of hydrogen peroxide formation catalyzed by small neutral gold clusters.

    PubMed

    Kacprzak, Katarzyna A; Akola, Jaakko; Häkkinen, Hannu

    2009-08-14

    Energetics and dynamical pathways for hydrogen peroxide formation from H(2) and O(2) bound to neutral gold dimers and tetramers have been investigated by applying several strategies: T = 0 K geometry optimizations, constrained Car-Parrinello molecular dynamics simulations at T = 300 K and metadynamics at T = 300 K. The competing reaction channels for water and hydrogen peroxide formation have been found and characterized. In each case, the reaction barriers for Au cluster catalyzed proton transfer are less than 1 eV. Water formation is a competitive reaction channel, and the relative weight of H(2)O and H(2)O(2) products may depend on the chosen Au cluster size. Dynamic simulations demonstrate the significance of the geometric fluxionality of small catalytic Au clusters. These results indicate that neutral Au clusters could work as catalysts in aerobic H(2)O(2) formation in ambient conditions.

  11. Contaminated Groundwater Remediation by Catalyzed Hydrogen Peroxide and Persulfate Oxidants System

    NASA Astrophysics Data System (ADS)

    Yan, N.; Wang, Y.; Brusseau, M. L.

    2014-12-01

    A binary oxidant system, catalyzed hydrogen peroxide (H2O2) coupled with persulfate (S2O82-), was investigated for use in in-situ chemical oxidation (ISCO) applications. Trichloroethene (TCE) and 1,4-dioxane were used as target contaminants. Batch experiments were conducted to investigate the catalytic efficiency between ferrous ion (Fe2+) and base (NaOH), oxidant decomposition rates, and contaminant degradation efficiency. For the base-catalyzed H2O2-S2O82- system, oxidant release was moderate and sustained over the entire test period of 96 hours. Conversely, the oxidants were depleted within 24 hours for the Fe2+-catalyzed system. Solution pH decreased slightly for the Fe2+-catalyzed system, whereas the pH increased for the base-catalyzed system. The rates of degradation for TCE and 1,4-dioxane are compared as a function of system conditions. The results of this study indicate that the binary H2O2-S2O82- oxidant system is effective for oxidation of the tested contaminants.

  12. [Removal of fluorescent whitening agent by hydrogen peroxide oxidation catalyzed by activated carbon].

    PubMed

    Liu, Hai-Long; Zhang, Zhong-Min; Zhao, Xia; Jiao, Ru-Yuan

    2014-06-01

    Degradation of fluorescent whitening agent VBL in the processes of activated carbon (AC) and activated carbon modified (ACM) adsorptions, hydrogen peroxide (H2O2) oxidation, and hydrogen peroxide oxidation catalyzed by activated carbon were studied. Mechanism of the above catalytic oxidation was also investigated by adding tert-Butyl alcohol (TBA), the free radical scavenger, and detecting the released gases. The results showed that: the activated carbon modified by Fe (NO3)3 (ACM)exhibited better adsorption removal than AC. Catalytic oxidation showed efficient removal of VBL, and the catalytic removal of AC (up to 95%) was significantly higher than that of ACM (58% only). Catalytic oxidation was inhibited by TBA, which indicates that the above reaction involved *OH radicals and atom oxygen generated by hydrogen peroxide with the presence of AC. The results of H2O2 decomposition and released gases detection involved in the process showed that activated carbon enhanced the decomposition of H2O2 which released oxygen and heat. More O2 was produced and higher temperature of the reactor was achieved, which indicated that H2O2 decomposition catalyzed by ACM was significantly faster than that of AC. Combining the results of VBL removal, it could be concluded that the rate of active intermediates (*OH radicals and atom oxygen) production by ACM catalytic reaction was faster than that of AC. These intermediates consumed themselves and produced O2 instead of degrading VBL. It seemed that the improper mutual matching of the forming rate of activating intermediates and the supply rate of reactants was an important reason for the lower efficiency of ACM catalytic reaction comparing with AC.

  13. Acid-catalyzed heterogeneous reaction of 3-methyl-2-buten-1-ol with hydrogen peroxide.

    PubMed

    Liu, Qifan; Wang, Weigang; Ge, Maofa

    2015-05-01

    Acid-catalyzed heterogeneous oxidation with hydrogen peroxide (H2O2) has been suggested to be a potential pathway for secondary organic aerosol (SOA) formation from isoprene and its oxidation products. However, knowledge of the chemical mechanism and kinetics for this process is still incomplete. 3-Methyl-2-buten-1-ol (MBO321), an aliphatic alcohol structurally similar to isoprene, is emitted by pine forests and widely used in the manufacturing industries. Herein the uptake of MBO321 into H2SO4-H2O2 mixed solution was investigated using a flow-tube reactor coupled to a mass spectrometer. The reactive uptake coefficients (γ) were acquired for the first time and were found to increase rapidly with increasing acid concentration. Corresponding aqueous-phase reactions were performed to further study the mechanism of this acid-catalyzed reaction. MBO321 could convert to 2-methyl-3-buten-2-ol (MBO232) and yield isoprene in acidic media. Organic hydroperoxides (ROOHs) were found to be generated through the acid-catalyzed route, which could undergo a rearrangement reaction and result in the formation of acetone and acetaldehyde. Organosulfates, which have been proposed to be SOA tracer compounds in the atmosphere, were also produced during the oxidation process. These results suggest that the heterogeneous acid-catalyzed reaction of MBO321 with H2O2 may contribute to SOA mass under certain atmospheric conditions. Copyright © 2015. Published by Elsevier B.V.

  14. Epoxidation of styrenes by hydrogen peroxide as catalyzed by methylrhenium trioxide

    SciTech Connect

    Al-Ajlouni, A.M.; Espenson, J.H. |

    1995-09-13

    Methylrhenium trioxide, CH{sub 3}ReO{sub 3}, catalyzes the oxidation of styrenes by hydrogen peroxide. Kinetic studies by three methods were carried out in acidic CH{sub 3}CN/H{sub 2}O (1:1 v/v) solutions. The catalytically-active species are the mono-peroxide, CH{sub 3}Rc(O){sub 2}(O{sub 2}), A, and the bis-peroxide, CH{sub 3}Re(O)(O{sub 2}){sub 2}, B, which epoxidize a given styrene at a similar rate. The rate constants are relatively insensitive to steric hindrance, but increase with the nucleophilicity of the styrene, electron-donating groups on the olefinic carbons or on the aromatic ring enhancing the rate. The rate constants for meta- and para-substituted styrenes follow a linear Hammett relationship; correlation with {sigma}{sup +} gave {rho} = -0.93 {+-} 0.05. In CD{sub 3}CN, epoxides were observed by {sup 1}H NMR spectroscopy. cis-{beta}-Methylstyrene and trans-{beta}-methylstyrene led to the cis epoxide and the trans epoxide, respectively. In acidic CH{sub 3}CN/H{sub 2}O, the major products were 1,2-diols. In some cases C-C bond cleavage products were also observed, the extreme case being {beta}-methoxystyrene where the C-C bond was completely cleaved to yield benzaldehyde, formaldehyde, and methanol. 32 refs., 7 figs., 2 tabs.

  15. Salicylic acid-induced superoxide generation catalyzed by plant peroxidase in hydrogen peroxide-independent manner.

    PubMed

    Kimura, Makoto; Kawano, Tomonori

    2015-01-01

    It has been reported that salicylic acid (SA) induces both immediate spike and long lasting phases of oxidative burst represented by the generation of reactive oxygen species (ROS) such as superoxide anion radical (O2(•-)). In general, in the earlier phase of oxidative burst, apoplastic peroxidase are likely involved and in the late phase of the oxidative burst, NADPH oxidase is likely involved. Key signaling events connecting the 2 phases of oxidative burst are calcium channel activation and protein phosphorylation events. To date, the known earliest signaling event in response to exogenously added SA is the cell wall peroxidase-catalyzed generation of O2(•-) in a hydrogen peroxide (H2O2)-dependent manner. However, this model is incomplete since the source of the initially required H2O2 could not be explained. Based on the recently proposed role for H2O2-independent mechanism for ROS production catalyzed by plant peroxidases (Kimura et al., 2014, Frontiers in Plant Science), we hereby propose a novel model for plant peroxidase-catalyzed oxidative burst fueled by SA.

  16. Salicylic acid-induced superoxide generation catalyzed by plant peroxidase in hydrogen peroxide-independent manner

    PubMed Central

    Kimura, Makoto; Kawano, Tomonori

    2015-01-01

    It has been reported that salicylic acid (SA) induces both immediate spike and long lasting phases of oxidative burst represented by the generation of reactive oxygen species (ROS) such as superoxide anion radical (O2•−). In general, in the earlier phase of oxidative burst, apoplastic peroxidase are likely involved and in the late phase of the oxidative burst, NADPH oxidase is likely involved. Key signaling events connecting the 2 phases of oxidative burst are calcium channel activation and protein phosphorylation events. To date, the known earliest signaling event in response to exogenously added SA is the cell wall peroxidase-catalyzed generation of O2•− in a hydrogen peroxide (H2O2)-dependent manner. However, this model is incomplete since the source of the initially required H2O2 could not be explained. Based on the recently proposed role for H2O2-independent mechanism for ROS production catalyzed by plant peroxidases (Kimura et al., 2014, Frontiers in Plant Science), we hereby propose a novel model for plant peroxidase-catalyzed oxidative burst fueled by SA. PMID:26633563

  17. Hydrogen peroxide poisoning

    MedlinePlus

    Hydrogen peroxide is used in these products: Hydrogen peroxide Hair bleach Some contact lens cleaners Note: Household hydrogen peroxide has a 3% concentration. That means it contains 97% water and 3% hydrogen peroxide. Hair ...

  18. Endothelial cell injury due to copper-catalyzed hydrogen peroxide generation from homocysteine.

    PubMed

    Starkebaum, G; Harlan, J M

    1986-04-01

    We have examined whether the toxic effects of homocysteine on cultured endothelial cells could result from the formation and action of hydrogen peroxide. In initial experiments with a cell-free system, micromolar amounts of copper were found to catalyze an oxygen-dependent oxidation of homocysteine. The molar ratio of homocysteine oxidized to oxygen consumed was approximately 4.0, which suggests that oxygen was reduced to water. The addition of catalase, however, decreased oxygen consumption by nearly one-half, which suggests that H2O2 was formed during the reaction. Confirming this hypothesis, H2O2 formation was detected using the horseradish peroxidase-dependent oxidation of fluorescent scopoletin. Ceruloplasmin was also found to catalyze oxidation of homocysteine and generation of H2O2 in molar amounts equivalent to copper sulfate. Finally, homocysteine oxidation was catalyzed by normal human serum in a concentration-dependent manner. Using cultured human and bovine endothelial cells, we found that homocysteine plus copper could lyse the cells in a dose-dependent manner, an effect that was completely prevented by catalase. Homocystine plus copper was not toxic to the cells. Specific injury to endothelial cells was seen only after 4 h of incubation with homocysteine plus copper. Confirming the biochemical studies, ceruloplasmin was also found to be equivalent to Cu++ in its ability to cause injury to endothelial cells in the presence of homocysteine. Since elevated levels of homocysteine have been implicated in premature development of atherosclerosis, these findings may be relevant to the mechanism of some types of chronic vascular injury.

  19. Biomimetic oxidation of curcumin with hydrogen peroxide catalyzed by 5,10,15,20-tetraarylporphyrinatoiron(III) chlorides in dichloromethane.

    PubMed

    Chauhan, Shive Murat Singh; Kandadai, Appan Srinivas; Jain, Nidhi; Kumar, Anil

    2003-11-01

    The biomimetic oxidation of curcumin, a main turmeric pigment with hydrogen peroxide catalyzed by different 5,10,15,20-tetraarylporphyrinatoiron(III) chlorides [TAPFe(III)Cl] in dichloromethane has been studied to give a C-C coupled curcumin dimer in 40-70% yield. The structure of the dimer has been elucidated by (1)H-, (13)C-NMR, IR and FAB-Mass spectroscopic data.

  20. Hydrogen peroxide catalytic decomposition

    NASA Technical Reports Server (NTRS)

    Parrish, Clyde F. (Inventor)

    2010-01-01

    Nitric oxide in a gaseous stream is converted to nitrogen dioxide using oxidizing species generated through the use of concentrated hydrogen peroxide fed as a monopropellant into a catalyzed thruster assembly. The hydrogen peroxide is preferably stored at stable concentration levels, i.e., approximately 50%-70% by volume, and may be increased in concentration in a continuous process preceding decomposition in the thruster assembly. The exhaust of the thruster assembly, rich in hydroxyl and/or hydroperoxy radicals, may be fed into a stream containing oxidizable components, such as nitric oxide, to facilitate their oxidation.

  1. Kinetics of the Oxidation of Hydrazine by Hydrogen Peroxide, Catalyzed by Copper (II)

    DTIC Science & Technology

    1975-08-01

    the reaction involves copper ion and hydrogen peroxide. Since copp~er(II) has been shawn to react slowly with hydrogen peroxide,5’,10 the miore...NUMBER 7. AUTHOR(s) 0 CONTRACT OR GRANT NUMBER(a) Carl R. Wellman J. Richard Ward !.ester P. Kuhn 9. PERFORMING ORGANIZATION NAME AND ADDRESS 10. PROGRAM...NAME AND ADDRESS 12. REPORT DATE U.S. Army Materiel Command AUGUST 1975) 5001 Eisenhower Av’enue .NUEROPAS AlexandriaV ; 2 IC. MONITORING ASANC NAME

  2. Growth and Detachment of Oxygen Bubbles Induced by Gold-Catalyzed Decomposition of Hydrogen Peroxide

    PubMed Central

    2017-01-01

    Whereas bubble growth out of gas-oversatured solutions has been quite well understood, including the formation and stability of surface nanobubbles, this is not the case for bubbles forming on catalytic surfaces due to catalytic reactions, though it has important implications for gas evolution reactions and self-propulsion of micro/nanomotors fueled by bubble release. In this work we have filled this gap by experimentally and theoretically examining the growth and detachment dynamics of oxygen bubbles from hydrogen peroxide decomposition catalyzed by gold. We measured the bubble radius R(t) as a function of time by confocal microscopy and find R(t) ∝ t1/2. This diffusive growth behavior demonstrates that the bubbles grow from an oxygen-oversaturated environment. For several consecutive bubbles detaching from the same position in a short period of time, a well-repeated growing behavior is obtained from which we conclude the absence of noticeable depletion effect of oxygen from previous bubbles or increasing oversaturation from the gas production. In contrast, for two bubbles far apart either in space or in time, substantial discrepancies in their growth rates are observed, which we attribute to the variation in the local gas oversaturation. The current results show that the dynamical evolution of bubbles is influenced by comprehensive effects combining chemical catalysis and physical mass transfer. Finally, we find that the size of the bubbles at the moment of detachment is determined by the balance between buoyancy and surface tension and by the detailed geometry at the bubble’s contact line. PMID:28983387

  3. Growth and Detachment of Oxygen Bubbles Induced by Gold-Catalyzed Decomposition of Hydrogen Peroxide.

    PubMed

    Lv, Pengyu; Le The, Hai; Eijkel, Jan; Van den Berg, Albert; Zhang, Xuehua; Lohse, Detlef

    2017-09-28

    Whereas bubble growth out of gas-oversatured solutions has been quite well understood, including the formation and stability of surface nanobubbles, this is not the case for bubbles forming on catalytic surfaces due to catalytic reactions, though it has important implications for gas evolution reactions and self-propulsion of micro/nanomotors fueled by bubble release. In this work we have filled this gap by experimentally and theoretically examining the growth and detachment dynamics of oxygen bubbles from hydrogen peroxide decomposition catalyzed by gold. We measured the bubble radius R(t) as a function of time by confocal microscopy and find R(t) ∝ t(1/2). This diffusive growth behavior demonstrates that the bubbles grow from an oxygen-oversaturated environment. For several consecutive bubbles detaching from the same position in a short period of time, a well-repeated growing behavior is obtained from which we conclude the absence of noticeable depletion effect of oxygen from previous bubbles or increasing oversaturation from the gas production. In contrast, for two bubbles far apart either in space or in time, substantial discrepancies in their growth rates are observed, which we attribute to the variation in the local gas oversaturation. The current results show that the dynamical evolution of bubbles is influenced by comprehensive effects combining chemical catalysis and physical mass transfer. Finally, we find that the size of the bubbles at the moment of detachment is determined by the balance between buoyancy and surface tension and by the detailed geometry at the bubble's contact line.

  4. Small-Scale Kinetic Study of the Catalyzed Decomposition of Hydrogen Peroxide

    NASA Astrophysics Data System (ADS)

    Ragsdale, Ronald O.; Vanderhooft, Jan C.; Zipp, Arden P.

    1998-02-01

    The rate of decomposition of hydrogen peroxide with pyrolusite as a catalyst was studied directly by following the formation of oxygen bubbles. The apparatus consisted of a barrel from a 2-ml Beral pipet inserted over a micropipet tip which was fitted into a one-hole stopper. The stopper assembly was placed in a 20-mL glass bottle reaction vessel. The hydrogen peroxide can be obtained from the super market and the catalyst, a piece of pyrolusite, can be recycled. The reaction order was found to be 1.1 + 0.2 by 240 pairs of students. The activation energy was 35 + 14 kJ. Reproducible data have also been obtained with the minerals, psilomelane, maganite, and groutite as catalysts.

  5. Concentration of Hydrogen Peroxide

    NASA Technical Reports Server (NTRS)

    Parrish, Clyde F. (Inventor)

    2006-01-01

    Methods for concentrating hydrogen peroxide solutions have been described. The methods utilize a polymeric membrane separating a hydrogen peroxide solution from a sweep gas or permeate. The membrane is selective to the permeability of water over the permeability of hydrogen peroxide, thereby facilitating the concentration of the hydrogen peroxide solution through the transport of water through the membrane to the permeate. By utilizing methods in accordance with the invention, hydrogen peroxide solutions of up to 85% by volume or higher may be generated at a point of use without storing substantial quantities of the highly concentrated solutions and without requiring temperatures that would produce explosive mixtures of hydrogen peroxide vapors.

  6. Kinetic studies on enzyme-catalyzed reactions: oxidation of glucose, decomposition of hydrogen peroxide and their combination.

    PubMed

    Tao, Zhimin; Raffel, Ryan A; Souid, Abdul-Kader; Goodisman, Jerry

    2009-04-08

    The kinetics of the glucose oxidase-catalyzed reaction of glucose with O2, which produces gluconic acid and hydrogen peroxide, and the catalase-assisted breakdown of hydrogen peroxide to generate oxygen, have been measured via the rate of O2 depletion or production. The O2 concentrations in air-saturated phosphate-buffered salt solutions were monitored by measuring the decay of phosphorescence from a Pd phosphor in solution; the decay rate was obtained by fitting the tail of the phosphorescence intensity profile to an exponential. For glucose oxidation in the presence of glucose oxidase, the rate constant determined for the rate-limiting step was k = (3.0 +/- 0.7) x 10(4) M(-1) s(-1) at 37 degrees C. For catalase-catalyzed H2O2 breakdown, the reaction order in [H2O2] was somewhat greater than unity at 37 degrees C and well above unity at 25 degrees C, suggesting different temperature dependences of the rate constants for various steps in the reaction. The two reactions were combined in a single experiment: addition of glucose oxidase to glucose-rich cell-free media caused a rapid drop in [O2], and subsequent addition of catalase caused [O2] to rise and then decrease to zero. The best fit of [O2] to a kinetic model is obtained with the rate constants for glucose oxidation and peroxide decomposition equal to 0.116 s(-1) and 0.090 s(-1) respectively. Cellular respiration in the presence of glucose was found to be three times as rapid as that in glucose-deprived cells. Added NaCN inhibited O2 consumption completely, confirming that oxidation occurred in the cellular mitochondrial respiratory chain.

  7. Epoxidation of 1-Octene with hydrogen peroxide aqueous catalyzed by titania supported sulfonated coal

    NASA Astrophysics Data System (ADS)

    Nurhadi, Mukhamad

    2017-02-01

    Titania supported sulfonated coal was created as heterogeneous catalyst for epoxidation of 1-octene with aqueous hydrogen peroxide as oxidant at room temperature. The catalysts were prepared from coal that was sulfonated with H2SO4 (97%) and impregnated 7.2%wt with titanium(IV) isopropoxide (Ti(PrO)4). All catalysts coal (C), CS, Ti(7.2)-CS and Ti(7.2)-CSC were characterized by FTIR. The catalytic performance was tested for epoxidation of 1-octene with H2O2 aqueous as oxidant. It is found that Ti(7.2)-CS possessed the best catalytic performance and it gave the highest 1,2 epoxyoctene 322 µmol.

  8. Ruthenium-catalyzed oxidation of alkenes, alkynes, and alcohols to organic acids with aqueous hydrogen peroxide.

    PubMed

    Che, Chi-Ming; Yip, Wing-Ping; Yu, Wing-Yiu

    2006-09-18

    A protocol that adopts aqueous hydrogen peroxide as a terminal oxidant and [(Me3tacn)(CF3CO2)2Ru(III)(OH2)]CF3CO2 (1; Me3tacn = 1,4,7-trimethyl-1,4,7-triazacyclononane) as a catalyst for oxidation of alkenes, alkynes, and alcohols to organic acids in over 80% yield is presented. For the oxidation of cyclohexene to adipic acid, the loading of 1 can be lowered to 0.1 mol %. On the one-mole scale, the oxidation of cyclohexene, cyclooctene, and 1-octanol with 1 mol % of 1 produced adipic acid (124 g, 85% yield), suberic acid (158 g, 91% yield), and 1-octanoic acid (129 g, 90% yield), respectively. The oxidative C=C bond-cleavage reaction proceeded through the formation of cis- and trans-diol intermediates, which were further oxidized to carboxylic acids via C-C bond cleavage.

  9. pH-Dependent reactivity of oxidants formed by iron and copper-catalyzed decomposition of hydrogen peroxide.

    PubMed

    Lee, Hongshin; Lee, Hye-Jin; Sedlak, David L; Lee, Changha

    2013-07-01

    The decomposition of hydrogen peroxide catalyzed by iron and copper leads to the generation of reactive oxidants capable of oxidizing various organic compounds. However, the specific nature of the reactive oxidants is still unclear, with evidence suggesting the production of hydroxyl radical or high-valent metal species. To identify the reactive species in the Fenton system, the oxidation of a series of different compounds (phenol, benzoic acid, methanol, Reactive Black 5 and arsenite) was studied for iron- and copper-catalyzed reactions at varying pH values. At lower pH values, more reactive oxidants appear to be formed in both iron and copper-catalyzed systems. The aromatic compounds, phenol and benzoic acid, were not oxidized under neutral or alkaline pH conditions, whereas methanol, Reactive Black 5, and arsenite were oxidized to a different degree, depending on the catalytic system. The oxidants responsible for the oxidation of compounds at neutral and alkaline pH values are likely to be high-valent metal complexes of iron and copper (i.e., ferryl and cupryl ions).

  10. Enhancing effect of DNA on chemiluminescence from the decomposition of hydrogen peroxide catalyzed by copper(II).

    PubMed

    Liu, Meilin; Li, Baoxin; Zhang, Zhujun; Lin, Jin-Ming

    2005-02-01

    In the absence of any special luminescence reagent, emission of weak chemiluminescence has been observed during the decomposition of hydrogen peroxide catalyzed by copper(II) in basic aqueous solution. The intensity of the chemiluminescence was greatly enhanced by addition of DNA and was strongly dependent on DNA concentration. Based on these phenomena, a flow-injection chemiluminescence method was established for determination of DNA. The chemiluminescence intensity was linear with DNA concentration in the range 2 x 10(-7)-1 x 10(-5) g L(-1) and the detection limit was 4.1 x 10(-8) g L(-1) (S/N=3). The relative standard deviation was less than 3.0% for 4 x 10(-7) g L(-1) DNA (n=11). The proposed method was satisfactorily applied for determination of DNA in synthetic samples. The possible mechanism of the CL reaction is discussed.

  11. Rate-Enhancing Roles of Water Molecules in Methyltrioxorhenium-Catalyzed Olefin Epoxidation by Hydrogen Peroxide.

    PubMed

    Goldsmith, Bryan R; Hwang, Taeho; Seritan, Stefan; Peters, Baron; Scott, Susannah L

    2015-08-05

    Olefin epoxidation catalyzed by methyltrioxorhenium (MTO, CH3ReO3) is strongly accelerated in the presence of H2O. The participation of H2O in each of the elementary steps of the catalytic cycle, involving the formation of the peroxo complexes (CH3ReO2(η(2)-O2), A, and CH3ReO(η(2)-O2)2(H2O), B), as well as in their subsequent epoxidation of cyclohexene, was examined in aqueous acetonitrile. Experimental measurements demonstrate that the epoxidation steps exhibit only weak [H2O] dependence, attributed by DFT calculations to hydrogen bonding between uncoordinated H2O and a peroxo ligand. The primary cause of the observed H2O acceleration is the strong co-catalytic effect of water on the rates at which A and B are regenerated and consequently on the relative abundances of the three interconverting Re-containing species at steady state. Proton transfer from weakly coordinated H2O2 to the oxo ligands of MTO and A, resulting in peroxo complex formation, is directly mediated by solvent H2O molecules. Computed activation parameters and kinetic isotope effects, in combination with proton-inventory experiments, suggest a proton shuttle involving one or (most favorably) two H2O molecules in the key ligand-exchange steps to form A and B from MTO and A, respectively.

  12. Degradation of trichloroethene by siderite-catalyzed hydrogen peroxide and persulfate: Investigation of reaction mechanisms and degradation products.

    PubMed

    Yan, Ni; Liu, Fei; Xue, Qiang; Brusseau, Mark L; Liu, Yali; Wang, Junjie

    2015-08-15

    A binary catalytic system, siderite-catalyzed hydrogen peroxide (H2O2) coupled with persulfate (S2O8(2-)), was investigated for the remediation of trichloroethene (TCE) contamination. Batch experiments were conducted to investigate reaction mechanisms, oxidant decomposition rates, and degradation products. By using high performance liquid chromatography (HPLC) coupled with electron paramagnetic resonance (EPR), we identified four radicals (hydroxyl (HO·), sulfate (SO4(-)·), hydroperoxyl (HO2·), and superoxide (O2(-)·)) in the siderite-catalyzed H2O2-S2O8(2-) system. In the absence of S2O8(2-) (i.e., siderite-catalyzed H2O2), a majority of H2O2 was decomposed in the first hour of the experiment, resulting in the waste of HO·. The addition of S2O8(2-) moderated the H2O2 decomposition rate, producing a more sustainable release of hydroxyl radicals that improved the treatment efficiency. Furthermore, the heat released by H2O2 decomposition accelerated the activation of S2O8(2-), and the resultant SO4(-)· was the primary oxidative agent during the first two hours of the reaction. Dichloroacetic acid was firstly detected by ion chromatography (IC). The results of this study indicate a new insight to the reaction mechanism for the catalytic binary H2O2-S2O8(2-) oxidant system, and the delineation of radicals and the discovery of the chlorinated byproduct provide useful information for efficient treatment of chlorinated-solvent contamination in groundwater.

  13. Degradation of trichloroethene by siderite-catalyzed hydrogen peroxide and persulfate: Investigation of reaction mechanisms and degradation products

    PubMed Central

    Yan, Ni; Liu, Fei; Xue, Qiang; Brusseau, Mark L.; Liu, Yali; Wang, Junjie

    2015-01-01

    A binary catalytic system, siderite-catalyzed hydrogen peroxide (H2O2) coupled with persulfate (S2O82−), was investigated for the remediation of trichloroethene (TCE) contamination. Batch experiments were conducted to investigate reaction mechanisms, oxidant decomposition rates, and degradation products. By using high performance liquid chromatography (HPLC) coupled with electron paramagnetic resonance (EPR), we identified four radicals (hydroxyl (HO·), sulfate (SO4−·), hydroperoxyl (HO2·), and superoxide (O2−·)) in the siderite-catalyzed H2O2-S2O82− system. In the absence of S2O82− (i.e., siderite-catalyzed H2O2), a majority of H2O2 was decomposed in the first hour of the experiment, resulting in the waste of HO·. The addition of S2O82− moderated the H2O2 decomposition rate, producing a more sustainable release of hydroxyl radicals that improved the treatment efficiency. Furthermore, the heat released by H2O2 decomposition accelerated the activation of S2O82−, and the resultant SO4−· was the primary oxidative agent during the first two hours of the reaction. Dichloroacetic acid was firstly detected by ion chromatography (IC). The results of this study indicate a new insight to the reaction mechanism for the catalytic binary H2O2-S2O82− oxidant system, and the delineation of radicals and the discovery of the chlorinated byproduct provide useful information for efficient treatment of chlorinated-solvent contamination in groundwater. PMID:26236152

  14. Cu-ZSM-5 catalyzed low-temperature hydrogen peroxide-induced methane-to-methanol conversion

    SciTech Connect

    Zhang, Yang; Li, Zhenglong; Allard, Jr., Lawrence Frederick; Kidder, Michelle; Narula, Chaitanya Kumar

    2017-01-01

    We report that Cu-ZSM-5 is an effective catalyst for methane oxidation with hydrogen peroxide. We find that synthesis via ion-exchage and reaction conditions are important factors for the observed efficiency of Cu-ZSM-5.

  15. Process conditions for the mineralization of a biorefractory polycyclic aromatic hydrocarbon in soils using catalyzed hydrogen peroxide

    SciTech Connect

    Stanton, P.C.; Watts, R.J.

    1996-12-31

    Catalyzed hydrogen peroxide (H{sub 2}O{sub 2} and soluble iron or mineral catalysts) was investigated as a basis for mineralizing benzo[a]pyrene (BaP), a hydrophobic and toxic polycyclic aromatic hydrocarbon, in two soils of varied complexity. The process is based on Fenton`s reagent, which can be implemented in soils to generate hydroxyl radicals. This short-lived species reacts with most organic contaminants at near diffusion-controlled rates, providing a mechanism for potential rapid soil remediation. Benzo[a]pyrene labeled with {sup 14}C was added to silica sand and a silt loam loess soil; mineralization processes were then optimized using central composite rotatable experimental designs. Variables investigated during the optimization included H{sub 2}O{sub 2} concentration, slurry volume, iron (II) amendment, and pH. Experimental data were evaluated by linear regression to develop empirical relationships and interactions between the variables. The equations were then used to develop three-dimensional response surfaces to describe BaP mineralization. The results from the response surfaces showed that 74% and 78% BaP mineralization was achieved in the silica sand and loess soils, respectively. The balance of the contaminant carbon remained with the soil fraction and was probably irreversibly sorbed. Desorption measurements over 5 d confirmed negligible desorption; however, oxidation reactions, which were complete within 24 h, documented >78% BaP mineralization, suggesting that the contaminant was oxidized, at least in part, in the sorbed phase. The results show that catalyzed H{sub 2}O{sub 2} has the ability to rapidly mineralize BaP that is not irreversibly sorbed.

  16. Hydrogen Peroxide Concentrator

    NASA Technical Reports Server (NTRS)

    Parrish, Clyde F.

    2007-01-01

    A relatively simple and economical process and apparatus for concentrating hydrogen peroxide from aqueous solution at the point of use have been invented. The heart of the apparatus is a vessel comprising an outer shell containing tubular membranes made of a polymer that is significantly more permeable by water than by hydrogen peroxide. The aqueous solution of hydrogen peroxide to be concentrated is fed through the interstitial spaces between the tubular membranes. An initially dry sweep gas is pumped through the interiors of the tubular membranes. Water diffuses through the membranes and is carried away as water vapor mixed into the sweep gas. Because of the removal of water, the hydrogen peroxide solution flowing from the vessel at the outlet end is more concentrated than that fed into the vessel at the inlet end. The sweep gas can be air, nitrogen, or any other gas that can be conveniently supplied in dry form and does not react chemically with hydrogen peroxide.

  17. Hydrogen peroxide inhibition of bicupin oxalate oxidase

    PubMed Central

    Goodwin, John M.; Rana, Hassan; Ndungu, Joan; Chakrabarti, Gaurab

    2017-01-01

    Oxalate oxidase is a manganese containing enzyme that catalyzes the oxidation of oxalate to carbon dioxide in a reaction that is coupled with the reduction of oxygen to hydrogen peroxide. Oxalate oxidase from Ceriporiopsis subvermispora (CsOxOx) is the first fungal and bicupin enzyme identified that catalyzes this reaction. Potential applications of oxalate oxidase for use in pancreatic cancer treatment, to prevent scaling in paper pulping, and in biofuel cells have highlighted the need to understand the extent of the hydrogen peroxide inhibition of the CsOxOx catalyzed oxidation of oxalate. We apply a membrane inlet mass spectrometry (MIMS) assay to directly measure initial rates of carbon dioxide formation and oxygen consumption in the presence and absence of hydrogen peroxide. This work demonstrates that hydrogen peroxide is both a reversible noncompetitive inhibitor of the CsOxOx catalyzed oxidation of oxalate and an irreversible inactivator. The build-up of the turnover-generated hydrogen peroxide product leads to the inactivation of the enzyme. The introduction of catalase to reaction mixtures protects the enzyme from inactivation allowing reactions to proceed to completion. Circular dichroism spectra indicate that no changes in global protein structure take place in the presence of hydrogen peroxide. Additionally, we show that the CsOxOx catalyzed reaction with the three carbon substrate mesoxalate consumes oxygen which is in contrast to previous proposals that it catalyzed a non-oxidative decarboxylation with this substrate. PMID:28486485

  18. Hydrogen peroxide inhibition of bicupin oxalate oxidase.

    PubMed

    Goodwin, John M; Rana, Hassan; Ndungu, Joan; Chakrabarti, Gaurab; Moomaw, Ellen W

    2017-01-01

    Oxalate oxidase is a manganese containing enzyme that catalyzes the oxidation of oxalate to carbon dioxide in a reaction that is coupled with the reduction of oxygen to hydrogen peroxide. Oxalate oxidase from Ceriporiopsis subvermispora (CsOxOx) is the first fungal and bicupin enzyme identified that catalyzes this reaction. Potential applications of oxalate oxidase for use in pancreatic cancer treatment, to prevent scaling in paper pulping, and in biofuel cells have highlighted the need to understand the extent of the hydrogen peroxide inhibition of the CsOxOx catalyzed oxidation of oxalate. We apply a membrane inlet mass spectrometry (MIMS) assay to directly measure initial rates of carbon dioxide formation and oxygen consumption in the presence and absence of hydrogen peroxide. This work demonstrates that hydrogen peroxide is both a reversible noncompetitive inhibitor of the CsOxOx catalyzed oxidation of oxalate and an irreversible inactivator. The build-up of the turnover-generated hydrogen peroxide product leads to the inactivation of the enzyme. The introduction of catalase to reaction mixtures protects the enzyme from inactivation allowing reactions to proceed to completion. Circular dichroism spectra indicate that no changes in global protein structure take place in the presence of hydrogen peroxide. Additionally, we show that the CsOxOx catalyzed reaction with the three carbon substrate mesoxalate consumes oxygen which is in contrast to previous proposals that it catalyzed a non-oxidative decarboxylation with this substrate.

  19. Coating for components requiring hydrogen peroxide compatibility

    NASA Technical Reports Server (NTRS)

    Yousefiani, Ali (Inventor)

    2010-01-01

    The present invention provides a heretofore-unknown use for zirconium nitride as a hydrogen peroxide compatible protective coating that was discovered to be useful to protect components that catalyze the decomposition of hydrogen peroxide or corrode when exposed to hydrogen peroxide. A zirconium nitride coating of the invention may be applied to a variety of substrates (e.g., metals) using art-recognized techniques, such as plasma vapor deposition. The present invention further provides components and articles of manufacture having hydrogen peroxide compatibility, particularly components for use in aerospace and industrial manufacturing applications. The zirconium nitride barrier coating of the invention provides protection from corrosion by reaction with hydrogen peroxide, as well as prevention of hydrogen peroxide decomposition.

  20. Activation of aqueous hydrogen peroxide for non-catalyzed dihydroperoxidation of ketones by azeotropic removal of water.

    PubMed

    Starkl Renar, K; Pečar, S; Iskra, J

    2015-09-28

    Cyclic and acyclic ketones were selectively converted to gem-dihydroperoxides in 72-99% yield with 30% aq. hydrogen peroxide by azeotropic distillation of water from the reaction mixture without any catalyst. The reactions were more selective than with 100% H2O2 and due to neutral conditions also less stable products could be obtained.

  1. [Luminol oxidation by hydrogen peroxide with chemiluminescent signal formation catalyzed by peroxygenase from the fungus Agrocybe aegerita V.Brig].

    PubMed

    Vdovenko, M M; Ulrich, R; Hofrichter, M; Sakharov, I Iu

    2010-01-01

    Conditions of luminol oxidation by hydrogen peroxide in the presence of peroxygenase from the mushroom Agrocybe aegerita V.Brig have been optimized. The pH value (8.8) at which fungal peroxygenase produces a maximum chemiluminescent signal has been shown to be similar to the pH optimum value of horseradish peroxidase. Luminescence intensity changed when the concentration of Tris buffer was varied; maximum intensity of chemiluminescence was observed in 40 mM solution. It has been shown that enhancer (p-iodophenol) addition to the substrate mixture containing A. aegerita peroxygenase exerted almost no influence on the intensity of the chemiluminescent signal, similarly to soybean, palm, and sweet potato peroxidases. Enzyme detection limit in the reaction of luminol oxidation by hydrogen peroxide was 0.8 pM. High stability combined with high sensitivity make this enzyme a promising analytical reagent.

  2. Electrochemical Hydrogen Peroxide Generator

    NASA Technical Reports Server (NTRS)

    Tennakoon, Charles L. K.; Singh, Waheguru; Anderson, Kelvin C.

    2010-01-01

    Two-electron reduction of oxygen to produce hydrogen peroxide is a much researched topic. Most of the work has been done in the production of hydrogen peroxide in basic media, in order to address the needs of the pulp and paper industry. However, peroxides under alkaline conditions show poor stabilities and are not useful in disinfection applications. There is a need to design electrocatalysts that are stable and provide good current and energy efficiencies to produce hydrogen peroxide under acidic conditions. The innovation focuses on the in situ generation of hydrogen peroxide using an electrochemical cell having a gas diffusion electrode as the cathode (electrode connected to the negative pole of the power supply) and a platinized titanium anode. The cathode and anode compartments are separated by a readily available cation-exchange membrane (Nafion 117). The anode compartment is fed with deionized water. Generation of oxygen is the anode reaction. Protons from the anode compartment are transferred across the cation-exchange membrane to the cathode compartment by electrostatic attraction towards the negatively charged electrode. The cathode compartment is fed with oxygen. Here, hydrogen peroxide is generated by the reduction of oxygen. Water may also be generated in the cathode. A small amount of water is also transported across the membrane along with hydrated protons transported across the membrane. Generally, each proton is hydrated with 3-5 molecules. The process is unique because hydrogen peroxide is formed as a high-purity aqueous solution. Since there are no hazardous chemicals or liquids used in the process, the disinfection product can be applied directly to water, before entering a water filtration unit to disinfect the incoming water and to prevent the build up of heterotrophic bacteria, for example, in carbon based filters. The competitive advantages of this process are: 1. No consumable chemicals are needed in the process. The only raw materials

  3. Fe-catalyzed one-pot oxidative cleavage of unsaturated fatty acids into aldehydes with hydrogen peroxide and sodium periodate.

    PubMed

    Spannring, Peter; Yazerski, Vital; Bruijnincx, Pieter C A; Weckhuysen, Bert M; Klein Gebbink, Robertus J M

    2013-10-25

    A one-pot method has been developed for the oxidative cleavage of internal alkenes into aldehydes by using 0.5 mol% of the nonheme iron complex [Fe(OTf)2(mix-bpbp)] (bpbp=N,N'-bis(2-picolyl)-2,2'-bipyrrolidine) as catalyst and 1.5 equivalents of hydrogen peroxide and 1 equivalent of sodium periodate as oxidants. A mixture of diastereomers of the chiral bpbp ligand can be used, thereby omitting the need for resolution of its optically active components. The cleavage reaction can be performed in one pot within 20 h and under ambient conditions. Addition of water after the epoxidation, acidification and subsequent pH neutralization are crucial to perform the epoxidation, hydrolysis, and subsequent diol cleavage in one pot. High aldehyde yields can be obtained for the cleavage of internal aliphatic double bonds with cis and trans configuration (86-98%) and unsaturated fatty acids and esters (69-96%). Good aldehyde yields are obtained in reactions of trisubstituted and terminal alkenes (62-63%). The products can be easily isolated by a simple extraction step with an organic solvent. The presented protocol involves a lower catalyst loading than conventional methods based on Ru or Os. Also, hydrogen peroxide can be used as the oxidant in this case, which is often disproportionated by second- and third-row metals. By using only mild oxidants, overoxidation of the aldehyde to the carboxylic acid is prevented. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  4. Baeyer-Villiger oxidation of cyclic ketones with hydrogen peroxide catalyzed by cationic complexes of platinum(II): Selectivity properties and mechanistic studies

    SciTech Connect

    Del Todesco Frisone, M.; Pinna, F.; Strukul, G. )

    1993-01-01

    The catalytic oxidation of simple cyclic ketones with hydrogen peroxide to give the corresponding lactones is reported. The reaction is catalyzed by complexes of Pt(II) of the type [(P-P)Pt(CF[sub 3])(solv)][sup +] (P-P = diphosphine) that may be deactivated by the hydroxy acids formed by hydrolysis of the lactones. The selectivity of the catalyst is studied in the oxidation of substrates like camphor, 2-cyclohexene-1-one, menthone, carvone, and indanones. Cyclobutanone is used to determine the mechanism of the reaction from initial rates studies. The reaction scheme proposed, which accounts for the observed effects of the various reactants, involves the coordination of the ketone on the vacant coordination site of the complex followed by nucleophilic attack of free hydrogen peroxide on the carbonyl carbon. The involvement of a quasi-peroxymetallacyclic intermediate is suggested which rearranges to give the lactone and the starting complex. A comparison with the mechanistic behavior of organic peroxy acids is given. 24 refs., 10 figs., 3 tabs.

  5. Effect of benzoic acid on the removal of 1,2-dichloroethane by a siderite-catalyzed hydrogen peroxide and persulfate system.

    PubMed

    Li, Shengpin; Li, Mengjiao; Luo, Ximing; Huang, Guoxin; Liu, Fei; Chen, Honghan

    2016-01-01

    Benzoic acid can affect the iron-oxide mineral dissolution and react with hydroxyl radical. This study investigated its effect on 1,2-dichloroethane removal process by siderite-catalyzed hydrogen peroxide and persulfate. The variation of benzoic acid concentrations can affect pH value and soluble iron concentrations; when benzoic acid varied from 0 to 0.5 mmol/L, pH increased while Fe(2+) and Fe(3+) concentrations decreased, resulting in 1,2-dichloroethane removal efficiency which decreased from 91.2 to 5.0%. However, when benzoic acid varied from 0.5 to 10 mmol/L, pH decreased while Fe(2+) and Fe(3+) concentrations increased, resulting in 1,2-dichloroethane removal efficiency which increased from 5.0 to 83.4%.

  6. Oxidative Cyclization of 1,5-Dienes with Hydrogen Peroxide Catalyzed by an Osmium(III) Complex: Synthesis of cis-Tetrahydrofurans.

    PubMed

    Sugimoto, Hideki; Kanetake, Takayuki; Maeda, Kazuki; Itoh, Shinobu

    2016-03-18

    Stereoselective oxidative cyclization of 1,5-dienes with hydrogen peroxide catalyzed by [Os(III)(OH)(H2O)(L-N4Me2)](PF6)2 (1: L-N4Me2 = N,N'-dimethyl-2,11-diaza-[3,3](2,6)pyridinophane) is explored. 1,5-Dienes involving geraniol derivatives are converted to the corresponding tetrahydrofurans in modest to high yields. The products exclusively have the cis-conformation with respect to the substituents at the 2- and 5-positions of the tetrahydrofuran ring. The products also have a syn-conformation with respect to the furan oxygen atom and the hydroxyl groups. Mechanistic studies including a direct reaction of the oxo-hydroxo-osmium(V) complex, 2, with a dihydroxylated geraniol derivative are performed.

  7. Greener Selective Cycloalkane Oxidations with Hydrogen Peroxide Catalyzed by Copper-5-(4-pyridyl)tetrazolate Metal-Organic Frameworks.

    PubMed

    Martins, Luísa; Nasani, Rajendar; Saha, Manideepa; Mobin, Shaikh; Mukhopadhyay, Suman; Pombeiro, Armando

    2015-10-21

    Microwave assisted synthesis of the Cu(I) compound [Cu(µ₄-4-ptz)]n [1, 4-ptz=5-(4-pyridyl)tetrazolate] has been performed by employing a relatively easy method and within a shorter period of time compared to its sister compounds. The syntheses of the Cu(II) compounds [Cu₃(µ₃-4-ptz)₄(µ₂-N₃)₂(DMF)₂]n∙(DMF)2n (2) and [Cu(µ₂-4-ptz)₂(H₂O)₂]n (3) using a similar method were reported previously by us. MOFs 1-3 revealed high catalytic activity toward oxidation of cyclic alkanes (cyclopentane, -hexane and -octane) with aqueous hydrogen peroxide, under very mild conditions (at room temperature), without any added solvent or additive. The most efficient system (2/H₂O₂) showed, for the oxidation of cyclohexane, a turnover number (TON) of 396 (TOF of 40 h(-1)), with an overall product yield (cyclohexanol and cyclohexanone) of 40% relative to the substrate. Moreover, the heterogeneous catalytic systems 1-3 allowed an easy catalyst recovery and reuse, at least for four consecutive cycles, maintaining ca. 90% of the initial high activity and concomitant high selectivity.

  8. Real-time detection of hydrogen peroxide using microelectrodes in an ultrasonic enhanced heterogeneous Fenton process catalyzed by ferrocene.

    PubMed

    Lin, Jun; Xin, Qing; Gao, Xiumin

    2015-07-01

    Microelectrodes were used for real-time detection of hydrogen peroxide (H2O2) in a heterogeneous sono-Fenton system with ferrocene as the catalyst. The working mechanism of reactive blue 13 decolorization in a heterogeneous sono-Fenton system was investigated. Ultrasonic irradiation showed no effect on decolorization when used alone and did not enhance decolorization in the H2O2 system (43.0 % for H2O2 vs. 48.1 % for US+H2O2). However, a system with the presence of Fenton-like reagents achieved complete decolorization. Decolorization was greatly accelerated by the addition of ultrasonic irradiation. Thorough decolorization was achieved in 20 min in the heterogeneous sono-Fenton system, which was 30 min faster than in the heterogeneous Fenton system. Based on the data collected by microelectrodes, accelerated decomposition of H2O2 was also observed. Ultrasonic irradiation aided the ferrocene catalyst in liberating more •OH from Fenton reactions, leading to the faster decolorization.

  9. Temperature-induced bifurcations in the Cu(II)-catalyzed and catalyst-free hydrogen peroxide-thiosulfate oscillating reaction.

    PubMed

    Yuan, Ling; Gao, Qingyu; Zhao, Yuemin; Tang, Xiaodong; Epstein, Irving R

    2010-07-08

    We study the oxidation dynamics of thiosulfate ions by hydrogen peroxide in the presence of trace amounts of copper(II) using the reaction temperature as a control parameter in a continuous flow stirred tank reactor. The system displays period-doubling, aperodic, and mixed-mode oscillations at different temperatures. We are able to simulate these complex dynamics with a model proposed by Kurin-Csorgei et al. The model suggests that the Cu(2+)-containing term is not essential for the observed oscillations. We find small-amplitude and high-frequency oscillations in the catalyst-free experimental system. The reaction between H(2)O(2) and S(2)O(3)(2-) contains the core mechanism of the H(2)O(2)-S(2)O(3)(2-)-Cu(2+) and H(2)O(2)-S(2)O(3)(2-)-SO(3)(2-) oscillatory systems, while the Cu(2+) and SO(3)(2-) modulate the feedback loops so as to strengthen the oscillatory dynamics.

  10. A Modified Demonstration of the Catalytic Decomposition of Hydrogen Peroxide

    NASA Astrophysics Data System (ADS)

    Trujillo, Carlos Alexander

    2005-06-01

    A safer and cheaper version of the popular catalyzed decomposition of hydrogen peroxide demonstration commonly called the “Elephants’ Toothpaste” is presented. Hydrogen peroxide is decomposed in the presence of a surfactant by the enzyme catalase producing foam. Catalase has a higher activity compared with the traditional iodide and permits the use of diluted hydrogen peroxide solutions. The demonstration can be made with household products with similar amazing effects.

  11. Demonstration of the Catalytic Decomposition of Hydrogen Peroxide.

    ERIC Educational Resources Information Center

    Conklin, Alfred R. Jr.; Kessinger, Angela

    1996-01-01

    Describes a demonstration known as Elephant's Toothpaste in which the decomposition of hydrogen peroxide is catalyzed by iodide. Oxygen is released and soap bubbles are produced. The foam produced is measured, and results show a good relationship between the amount of foam and the concentration of the hydrogen peroxide. (DDR)

  12. Demonstration of the Catalytic Decomposition of Hydrogen Peroxide.

    ERIC Educational Resources Information Center

    Conklin, Alfred R. Jr.; Kessinger, Angela

    1996-01-01

    Describes a demonstration known as Elephant's Toothpaste in which the decomposition of hydrogen peroxide is catalyzed by iodide. Oxygen is released and soap bubbles are produced. The foam produced is measured, and results show a good relationship between the amount of foam and the concentration of the hydrogen peroxide. (DDR)

  13. Mechanistic study of iron(III) [tetrakis(pentafluorophenyl)porphyrin triflate (F(20)TPP)Fe(OTf) catalyzed cyclooctene epoxidation by hydrogen peroxide.

    PubMed

    Stephenson, Ned A; Bell, Alexis T

    2007-03-19

    We have recently proposed a mechanism for the epoxidation of cyclooctene by H2O2 catalyzed by iron(III) [tetrakis(pentafluorophenyl)]porphyrin chloride, (F20TPP)FeCl, in solvent containing methanol [Stephenson, N. A.; Bell, A.T. Inorg. Chem. 2006, 45, 2758-2766]. In that study, we found that catalysis did not occur unless (F20TPP)FeCl first dissociated, a process facilitated by the solvation of the Cl- anion by methanol and the coordination of methanol to the (F20TPP)Fe+ cation. Methanol as well as other alcohols was also found to facilitate the heterolytic cleavage of the O-O bond of H2O2 coordinated to the (F20TPP)Fe+ cation via a generalized acid mechanism. In the present study, we have shown that catalytic activity of the (F20TPP)Fe+ cation can be achieved in aprotic solvent by displacing the tightly bound chloride anion with a weakly bound triflate anion. By working in an aprotic solvent, acetonitrile, it was possible to determine the rate of heterolytic O-O bond cleavage in coordinated H2O2 unaffected by the interaction of the peroxide with methanol. A mechanism is proposed for this system and is shown to be valid over a range of reaction conditions. The mechanisms for cyclooctene epoxidation and H2O2 decomposition for the aprotic and protic solvent systems are similar with the only difference being the mechanism of proton-transfer prior to heterolytic cleavage of the oxygen-oxygen bond of coordinated hydrogen peroxide. Comparison of the rate parameters indicates that the utilization of hydrogen peroxide for cyclooctene epoxidation is higher in a protic solvent than in an aprotic solvent and results in a smaller extent of porphyrin degradation due to free radical attack. It was also shown that water can coordinate to the iron porphyrin cation in aprotic systems resulting in catalyst deactivation; this effect was not observed when methanol was present, since methanol was found to displace all of the coordinated water.

  14. Sensitive and selective capillary electrophoretic analysis of proteins by zirconia nanoparticle-enhanced copper (II)-catalyzed luminol-hydrogen peroxide chemiluminescence.

    PubMed

    Liu, Qingchun; Wu, Jingqing; Tian, Jing; Zhang, Chenling; Gao, Jingjie; Latep, Nurgul; Ge, Ying; Qin, Weidong

    2012-08-15

    We report herein a sensitive, selective, convenient CE determination of heme proteins in complex matrices by a sodium-dodecyl-sulfate-assisted, zirconia nanoparticle-enhanced copper (II)-catalyzed luminol-hydrogen peroxide chemiluminescence (CCLHPCL). Introducing a segment of sodium dodecyl sulfate to the capillary after sample injection not only rendered selective detection by quenching the luminescence signals from the non-heme proteins but also owning to the suppressed protein adsorption, led to significant improvement in separation efficiency and detection sensitivity. The signals were further improved by addition of ZrO(2) nanoparticles to the chemiluminescence solution. Compared with the conventional CCLHPCL, the detection limits (S/N=3) were improved by 10.2-22.0 folds, with 7.8×10(-9), 3.3×10(-9) and 1.5×10(-9) M for three model proteins, viz, myoglobin, hemoglobin and cytochrome C, respectively. Because the method did not require sophisticated pretreatment, it was convenient to analyze heme proteins in complex matrices, as demonstrated, hemoglobin in human blood and spiked human urine samples.

  15. Hydrogen peroxide stabilization in one-dimensional flow columns

    NASA Astrophysics Data System (ADS)

    Schmidt, Jeremy T.; Ahmad, Mushtaque; Teel, Amy L.; Watts, Richard J.

    2011-09-01

    Rapid hydrogen peroxide decomposition is the primary limitation of catalyzed H 2O 2 propagations in situ chemical oxidation (CHP ISCO) remediation of the subsurface. Two stabilizers of hydrogen peroxide, citrate and phytate, were investigated for their effectiveness in one-dimensional columns of iron oxide-coated and manganese oxide-coated sand. Hydrogen peroxide (5%) with and without 25 mM citrate or phytate was applied to the columns and samples were collected at 8 ports spaced 13 cm apart. Citrate was not an effective stabilizer for hydrogen peroxide in iron-coated sand; however, phytate was highly effective, increasing hydrogen peroxide residuals two orders of magnitude over unstabilized hydrogen peroxide. Both citrate and phytate were effective stabilizers for manganese-coated sand, increasing hydrogen peroxide residuals by four-fold over unstabilized hydrogen peroxide. Phytate and citrate did not degrade and were not retarded in the sand columns; furthermore, the addition of the stabilizers increased column flow rates relative to unstabilized columns. These results demonstrate that citrate and phytate are effective stabilizers of hydrogen peroxide under the dynamic conditions of one-dimensional columns, and suggest that citrate and phytate can be added to hydrogen peroxide before injection to the subsurface as an effective means for increasing the radius of influence of CHP ISCO.

  16. Hydrogen peroxide stabilization in one-dimensional flow columns.

    PubMed

    Schmidt, Jeremy T; Ahmad, Mushtaque; Teel, Amy L; Watts, Richard J

    2011-09-25

    Rapid hydrogen peroxide decomposition is the primary limitation of catalyzed H(2)O(2) propagations in situ chemical oxidation (CHP ISCO) remediation of the subsurface. Two stabilizers of hydrogen peroxide, citrate and phytate, were investigated for their effectiveness in one-dimensional columns of iron oxide-coated and manganese oxide-coated sand. Hydrogen peroxide (5%) with and without 25 mM citrate or phytate was applied to the columns and samples were collected at 8 ports spaced 13 cm apart. Citrate was not an effective stabilizer for hydrogen peroxide in iron-coated sand; however, phytate was highly effective, increasing hydrogen peroxide residuals two orders of magnitude over unstabilized hydrogen peroxide. Both citrate and phytate were effective stabilizers for manganese-coated sand, increasing hydrogen peroxide residuals by four-fold over unstabilized hydrogen peroxide. Phytate and citrate did not degrade and were not retarded in the sand columns; furthermore, the addition of the stabilizers increased column flow rates relative to unstabilized columns. These results demonstrate that citrate and phytate are effective stabilizers of hydrogen peroxide under the dynamic conditions of one-dimensional columns, and suggest that citrate and phytate can be added to hydrogen peroxide before injection to the subsurface as an effective means for increasing the radius of influence of CHP ISCO.

  17. Iodine-catalyzed 1,3-dipolar cycloaddition/oxidation/aromatization cascade with hydrogen peroxide as the terminal oxidant: general route to pyrrolo[2,1-a]isoquinolines.

    PubMed

    Huang, Huan-Ming; Li, Yu-Jin; Ye, Qing; Yu, Wu-Bin; Han, Liang; Jia, Jian-Hong; Gao, Jian-Rong

    2014-02-07

    We report a novel molecular iodine-catalyzed 1,3-dipolar cycloaddition/oxidation/aromatization cascade process with hydrogen peroxide as the terminal oxidant for the construction of pyrrolo[2,1-a]isoquinolines. The product pyrrolo[2,1-a]isoquinolines were obtained from reactions between simple, readily available dipolarophiles and tetrahydroisoquinolines in moderate to excellent yields without the need for a metal catalyst.

  18. Stabilized aqueous hydrogen peroxide solution

    SciTech Connect

    Malin, M.J.; Sciafani, L.D.

    1988-05-17

    This patent describes a stabilized aqueous hydrogen peroxide solution having a pH below 7 and an amount of Ferric ion up to about 2 ppm comprising hydrogen peroxide, acetanilide having a concentration which ranges between 0.74 M Mol/L and 2.22 mMol/L, and o-benzene disulfonic acid or salt thereof at a concentration between about 0.86 mMol/L to about 1.62 mMol/L.

  19. 21 CFR 173.356 - Hydrogen peroxide.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 3 2011-04-01 2011-04-01 false Hydrogen peroxide. 173.356 Section 173.356 Food... Specific Usage Additives § 173.356 Hydrogen peroxide. Hydrogen peroxide (CAS Reg. No. 7722-84-1) may be... to exceed 0.001 percent by weight of the whey, providing that residual hydrogen peroxide is...

  20. 21 CFR 173.356 - Hydrogen peroxide.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 3 2012-04-01 2012-04-01 false Hydrogen peroxide. 173.356 Section 173.356 Food... Specific Usage Additives § 173.356 Hydrogen peroxide. Hydrogen peroxide (CAS Reg. No. 7722-84-1) may be... to exceed 0.001 percent by weight of the whey, providing that residual hydrogen peroxide is removed...

  1. 21 CFR 173.356 - Hydrogen peroxide.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 3 2013-04-01 2013-04-01 false Hydrogen peroxide. 173.356 Section 173.356 Food... Specific Usage Additives § 173.356 Hydrogen peroxide. Hydrogen peroxide (CAS Reg. No. 7722-84-1) may be... to exceed 0.001 percent by weight of the whey, providing that residual hydrogen peroxide is removed...

  2. Highly Enantioselective Oxidation of Nonactivated Aliphatic C–H Bonds with Hydrogen Peroxide Catalyzed by Manganese Complexes

    PubMed Central

    2017-01-01

    Monosubstituted cycloalkanes undergo regio- and enantioselective aliphatic C–H oxidation with H2O2 catalyzed by biologically inspired manganese catalysts. The reaction furnishes the corresponding ketones resulting from oxidation at C3 and C4 methylenic sites (K3 and K4, respectively) leading to a chiral desymmetrization that proceeds with remarkable enantioselectivity (64% ee) but modest regioselectivity at C3 (K3/K4 ≈ 2) for tert-butylcyclohexane, and with up to 96% ee and exquisite regioselectity toward C3 (up to K3/K4 > 99) when N-cyclohexylalkanamides are employed as substrates. Efficient H2O2 activation, high yield, and highly enantioselective C–H oxidation rely on the synergistic cooperation of a sterically bulky manganese catalyst and an oxidatively robust alkanoic acid. This represents the first example of nonenzymatic highly enantioselective oxidation of nonactivated methylenic sites. Furthermore, the principles of catalyst design disclosed in this work constitute a unique platform for further development of stereoselective C–H oxidation reactions. PMID:28386597

  3. Association of poly(ADP-ribose) polymerase with nuclear subfractions catalyzed with sodium tetrathionate and hydrogene peroxide crosslinks.

    PubMed

    Desnoyers, S; Kirkland, J B; Poirier, G G

    1996-06-21

    Poly(ADP-ribose) polymerase (PARP) is a nuclear enzyme which catalyzes the transfer of ADP-ribose units from NAD+ to a variety of nuclear proteins under the stimulation of DNA strand break. To examine its role in DNA repair, we have been studying the interaction of PARP with other nuclear proteins using disulfide cross-linking, initiated by sodium tetrathionate (NaTT). Chinese Hamster Ovary (CHO) cells were extracted sequentially with Nonidet P40 (detergent), nucleases (DNase+RNase), and high salt (1.6 M NaCl) with and without the addition of a sulfhydryl reducing agent. The residual structures are referred to as the nuclear matrix, and are implicated in the organization of DNA repair and replication. Treatment of the cells with NaTT causes the crosslinking of PARP to the nuclear matrix. Activating PARP by pretreating the cells with H2O2 did not increase the cross-linking of PARP with the nuclear matrix, suggesting a lack of additional interaction of the enzyme with the nuclear matrix during DNA repair. Both NaTT and H2O2 induced crosslinks of PARP that were extractable with high salt. To shorten the procedure, these crosslinks were extracted from cells without nucleases and high salt treatment, using phosphate buffer. Using western blotting, these crosslinks appeared as a smear of high molecular weight species including a possible dimer of PARP at 230 kDa, which return to 116 kDa following reduction with beta-mercaptoethanol.

  4. 21 CFR 529.1150 - Hydrogen peroxide.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 6 2011-04-01 2011-04-01 false Hydrogen peroxide. 529.1150 Section 529.1150 Food... peroxide. (a) Specifications. Each milliliter of solution contains 396.1 milligrams (mg) hydrogen peroxide... group. Eggs: Some strains of rainbow trout eggs are sensitive to hydrogen peroxide treatment at a...

  5. 21 CFR 529.1150 - Hydrogen peroxide.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Hydrogen peroxide. 529.1150 Section 529.1150 Food... peroxide. (a) Specifications. Each milliliter of solution contains 396.1 milligrams (mg) hydrogen peroxide... group. Eggs: Some strains of rainbow trout eggs are sensitive to hydrogen peroxide treatment at a...

  6. 21 CFR 529.1150 - Hydrogen peroxide.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 6 2012-04-01 2012-04-01 false Hydrogen peroxide. 529.1150 Section 529.1150 Food... peroxide. (a) Specifications. Each milliliter of solution contains 396.1 milligrams (mg) hydrogen peroxide... group. Eggs: Some strains of rainbow trout eggs are sensitive to hydrogen peroxide treatment at a time...

  7. 21 CFR 529.1150 - Hydrogen peroxide.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 6 2013-04-01 2013-04-01 false Hydrogen peroxide. 529.1150 Section 529.1150 Food... peroxide. (a) Specifications. Each milliliter of solution contains 396.1 milligrams (mg) hydrogen peroxide... group. Eggs: Some strains of rainbow trout eggs are sensitive to hydrogen peroxide treatment at a time...

  8. Progress toward hydrogen peroxide micropulsion

    SciTech Connect

    Whitehead, J C; Dittman, M D; Ledebuhr, A G

    1999-07-08

    A new self-pressurizing propulsion system has liquid thrusters and gas jet attitude control without heavy gas storage vessels. A pump boosts the pressure of a small fraction of the hydrogen peroxide, so that reacted propellant can controllably pressurize its own source tank. The warm decomposition gas also powers the pump and is supplied to the attitude control jets. The system has been incorporated into a prototype microsatellite for terrestrial maneuvering tests. Additional progress includes preliminary testing of a bipropellant thruster, and storage of unstabilized hydrogen peroxide in small sealed tanks.

  9. 21 CFR 582.1366 - Hydrogen peroxide.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Hydrogen peroxide. 582.1366 Section 582.1366 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Additives § 582.1366 Hydrogen peroxide. (a) Product. Hydrogen peroxide. (b) (c) Limitations,...

  10. 21 CFR 582.1366 - Hydrogen peroxide.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 6 2011-04-01 2011-04-01 false Hydrogen peroxide. 582.1366 Section 582.1366 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Additives § 582.1366 Hydrogen peroxide. (a) Product. Hydrogen peroxide. (b) (c) Limitations,...

  11. Sampling Stoichiometry: The Decomposition of Hydrogen Peroxide.

    ERIC Educational Resources Information Center

    Clift, Philip A.

    1992-01-01

    Describes a demonstration of the decomposition of hydrogen peroxide to provide an interesting, quantitative illustration of the stoichiometric relationship between the decomposition of hydrogen peroxide and the formation of oxygen gas. This 10-minute demonstration uses ordinary hydrogen peroxide and yeast that can be purchased in a supermarket.…

  12. Sampling Stoichiometry: The Decomposition of Hydrogen Peroxide.

    ERIC Educational Resources Information Center

    Clift, Philip A.

    1992-01-01

    Describes a demonstration of the decomposition of hydrogen peroxide to provide an interesting, quantitative illustration of the stoichiometric relationship between the decomposition of hydrogen peroxide and the formation of oxygen gas. This 10-minute demonstration uses ordinary hydrogen peroxide and yeast that can be purchased in a supermarket.…

  13. 21 CFR 582.1366 - Hydrogen peroxide.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 6 2014-04-01 2014-04-01 false Hydrogen peroxide. 582.1366 Section 582.1366 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Additives § 582.1366 Hydrogen peroxide. (a) Product. Hydrogen peroxide. (b) (c) Limitations, restrictions...

  14. 21 CFR 582.1366 - Hydrogen peroxide.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 6 2013-04-01 2013-04-01 false Hydrogen peroxide. 582.1366 Section 582.1366 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Additives § 582.1366 Hydrogen peroxide. (a) Product. Hydrogen peroxide. (b) (c) Limitations, restrictions...

  15. 21 CFR 582.1366 - Hydrogen peroxide.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 6 2012-04-01 2012-04-01 false Hydrogen peroxide. 582.1366 Section 582.1366 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Additives § 582.1366 Hydrogen peroxide. (a) Product. Hydrogen peroxide. (b) (c) Limitations, restrictions...

  16. Improved dual flow aluminum hydrogen peroxide battery

    SciTech Connect

    Marsh, C.; Licht, S.L.; Matthews, D.

    1993-11-30

    A novel dual flow battery configuration is provided comprising an aqueous hydrogen peroxide catholyte, an aqueous anolyte, a porous solid electrocatalyst capable of reducing said hydrogen peroxide and separating said anolyte, and an aluminum anode positioned within said anolyte. Separation of catholyte and anolyte chambers prevents hydrogen peroxide poisoning of the aluminum anode.

  17. Improved dual flow aluminum hydrogen peroxide battery

    NASA Astrophysics Data System (ADS)

    Marsh, Catherine; Licht, Stuart L.; Matthews, Donna

    1993-11-01

    A novel dual flow battery configuration is provided comprising an aqueous hydrogen peroxide catholyte, an aqueous anolyte, a porous solid electrocatalyst capable of reducing said hydrogen peroxide and separating said anolyte, and an aluminum anode positioned within said anolyte. Separation of catholyte and anolyte chambers prevents hydrogen peroxide poisoning of the aluminum anode.

  18. 183W NMR Study of Peroxotungstates Involved in the Disproportionation of Hydrogen Peroxide into Singlet Oxygen ((1)O(2), (1)Delta(g)) Catalyzed by Sodium Tungstate in Neutral and Alkaline Water.

    PubMed

    Nardello, V.; Marko, J.; Vermeersch, G.; Aubry, J. M.

    1998-10-19

    The disproportionation of aqueous hydrogen peroxide catalyzed by sodium tungstate has been investigated with regard to the multiplicity of the oxygen molecules released. Trapping experiments and detection of the IR luminescence of (1)O(2) have shown that the yield of (1)O(2) is virtually quantitative. The mono-, di-, and tetraperoxotungstate intermediates W(O(2))(n)()O(4)(-)(n)()(2)(-) (n = 1, 2, 4) have been characterized by UV and (183)W NMR spectroscopies. The diperoxo species is proposed as the precursor of (1)O(2).

  19. Improved Electrolytic Hydrogen Peroxide Generator

    NASA Technical Reports Server (NTRS)

    James, Patrick I.

    2005-01-01

    An improved apparatus for the electrolytic generation of hydrogen peroxide dissolved in water has been developed. The apparatus is a prototype of H2O2 generators for the safe and effective sterilization of water, sterilization of equipment in contact with water, and other applications in which there is need for hydrogen peroxide at low concentration as an oxidant. Potential applications for electrolytic H2O2 generators include purification of water for drinking and for use in industrial processes, sanitation for hospitals and biotechnological industries, inhibition and removal of biofouling in heat exchangers, cooling towers, filtration units, and the treatment of wastewater by use of advanced oxidation processes that are promoted by H2O2.

  20. Detection of hydrogen peroxide with chemiluminescent micelles.

    PubMed

    Lee, Dongwon; Erigala, Venkata R; Dasari, Madhuri; Yu, Junhua; Dickson, Robert M; Murthy, Niren

    2008-01-01

    The overproduction of hydrogen peroxide is implicated in the progress of numerous life-threatening diseases and there is a great need for the development of contrast agents that can detect hydrogen peroxide in vivo. In this communication, we present a new contrast agent for hydrogen peroxide, termed peroxalate micelles, which detect hydrogen peroxide through chemiluminescence, and have the physical/chemical properties needed for in vivo imaging applications. The peroxalate micelles are composed of amphiphilic peroxalate based copolymers and the fluorescent dye rubrene, they have a 'stealth' polyethylene glycol (PEG) corona to evade macrophage phagocytosis, and a diameter of 33 nm to enhance extravasation into permeable tissues. The peroxalate micelles can detect nanomolar concentrations of hydrogen peroxide (>50 nM) and thus have the sensitivity needed to detect physiological concentrations of hydrogen peroxide. We anticipate numerous applications of the peroxalate micelles for in vivo imaging of hydrogen peroxide, given their high sensitivity, small size, and biocompatible PEG corona.

  1. NASA Hydrogen Peroxide Propulsion Perspective

    NASA Technical Reports Server (NTRS)

    Unger, Ronald; Lyles, Garry M. (Technical Monitor)

    2002-01-01

    This presentation is to provide the current status of NASA's efforts in the development of hydrogen peroxide in both mono-propellant and bi-propellant applications, consistent with the Space Launch Initiative goals of pursuing low toxicity and operationally simpler propellants for application in the architectures being considered for the 2nd Generation Reusable Launch Vehicle, also known as the Space Launch Initiative, or SLI.

  2. Diffusion of hydrogen peroxide across DPPC large unilamellar liposomes.

    PubMed

    Abuin, Elsa; Lissi, Eduardo; Ahumada, Manuel

    2012-09-01

    The decomposition of hydrogen peroxide catalyzed by catalase entrapped in the pool of dipalmitoylphosphatidyl choline unilamellar liposomes has been studied. The rate of the process was evaluated by following the production of oxygen as a function of time. Under the experimental conditions employed the rate of oxygen production was controlled by the diffusion of hydrogen peroxide, allowing for the estimation of the diffusion coefficient of hydrogen peroxide across the liposome bilayer. The rate of diffusion across the bilayer increases with the temperature and the presence of fluidizers (n-nonanol), according with changes in the bilayer fluidity, as sensed by 1,6-diphenyl hexatriene (DPH) fluorescence anisotropy. A peculiar aspect of the data is the fast hydrogen peroxide diffusion observed at the bilayer phase transition temperature. This fast diffusion is associated to rafts fluctuations that take place in the partially melted bilayer. These fluctuations have no effect on the microviscosity sensed by DPH. Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.

  3. Hydrogen peroxide and organic peroxides in the marine environment

    NASA Astrophysics Data System (ADS)

    Heikes, Brian G.; Miller, William L.; Lee, Meehye

    1991-05-01

    Aqueous fluorescence and chemiluminescence methods have been used to measure hydrogen peroxide in natural waters and in the atmosphere. Ambient hydrogen peroxide and soluble organic peroxide data is presented from the EMEX, MLOPEX and SAGA-3 experimental programs, experiments conducted in the remote marine environment. Methods to measure organic peroxide using conventional collection strategies and direct analysis by chemiluminescence or fluorescence method is approximately two orders of magnitude more sensitive than the fluorescence method. Species specific measurements of organic peroxides are also in development using high pressure liquid chromatography (HPLC) and fluorescence or chemiluminescence detection.

  4. High temperature decomposition of hydrogen peroxide

    NASA Technical Reports Server (NTRS)

    Parrish, Clyde F. (Inventor)

    2005-01-01

    Nitric oxide (NO) is oxidized into nitrogen dioxide (NO2) by the high temperature decomposition of a hydrogen peroxide solution to produce the oxidative free radicals, hydroxyl and hydroperoxyl. The hydrogen peroxide solution is impinged upon a heated surface in a stream of nitric oxide where it decomposes to produce the oxidative free radicals. Because the decomposition of the hydrogen peroxide solution occurs within the stream of the nitric oxide, rapid gas-phase oxidation of nitric oxide into nitrogen dioxide occurs.

  5. Hydrogen peroxide on the surface of Europa

    USGS Publications Warehouse

    Carlson, R.W.; Anderson, M.S.; Johnson, R.E.; Smythe, W.D.; Hendrix, A.R.; Barth, C.A.; Soderblom, L.A.; Hansen, G.B.; McCord, T.B.; Dalton, J.B.; Clark, R.N.; Shirley, J.H.; Ocampo, A.C.; Matson, D.L.

    1999-01-01

    Spatially resolved infrared and ultraviolet wavelength spectra of Europa's leading, anti-jovian quadrant observed from the Galileo spacecraft show absorption features resulting from hydrogen peroxide. Comparisons with laboratory measurements indicate surface hydrogen peroxide concentrations of about 0.13 percent, by number, relative to water ice. The inferred abundance is consistent with radiolytic production of hydrogen peroxide by intense energetic particle bombardment and demonstrates that Europa's surface chemistry is dominated by radiolysis.

  6. High Temperature Decomposition of Hydrogen Peroxide

    NASA Technical Reports Server (NTRS)

    Parrish, Clyde F. (Inventor)

    2004-01-01

    Nitric oxide (NO) is oxidized into nitrogen dioxide (NO2) by the high temperature decomposition of a hydrogen peroxide solution to produce the oxidative free radicals, hydroxyl and hydropemxyl. The hydrogen peroxide solution is impinged upon a heated surface in a stream of nitric oxide where it decomposes to produce the oxidative free radicals. Because the decomposition of the hydrogen peroxide solution occurs within the stream of the nitric oxide, rapid gas-phase oxidation of nitric oxide into nitrogen dioxide occurs.

  7. Hydrogen peroxide on the surface of Europa.

    PubMed

    Carlson, R W; Anderson, M S; Johnson, R E; Smythe, W D; Hendrix, A R; Barth, C A; Soderblom, L A; Hansen, G B; McCord, T B; Dalton, J B; Clark, R N; Shirley, J H; Ocampo, A C; Matson, D L

    1999-03-26

    Spatially resolved infrared and ultraviolet wavelength spectra of Europa's leading, anti-jovian quadrant observed from the Galileo spacecraft show absorption features resulting from hydrogen peroxide. Comparisons with laboratory measurements indicate surface hydrogen peroxide concentrations of about 0.13 percent, by number, relative to water ice. The inferred abundance is consistent with radiolytic production of hydrogen peroxide by intense energetic particle bombardment and demonstrates that Europa's surface chemistry is dominated by radiolysis.

  8. High temperature decomposition of hydrogen peroxide

    NASA Technical Reports Server (NTRS)

    Parrish, Clyde F. (Inventor)

    2005-01-01

    Nitric oxide (NO) is oxidized into nitrogen dioxide (NO2) by the high temperature decomposition of a hydrogen peroxide solution to produce the oxidative free radicals, hydroxyl and hydroperoxyl. The hydrogen peroxide solution is impinged upon a heated surface in a stream of nitric oxide where it decomposes to produce the oxidative free radicals. Because the decomposition of the hydrogen peroxide solution occurs within the stream of the nitric oxide, rapid gas-phase oxidation of nitric oxide into nitrogen dioxide occurs.

  9. High Temperature Decomposition of Hydrogen Peroxide

    NASA Technical Reports Server (NTRS)

    Parrish, Clyde F. (Inventor)

    2004-01-01

    Nitric oxide (NO) is oxidized into nitrogen dioxide (NO2) by the high temperature decomposition of a hydrogen peroxide solution to produce the oxidative free radicals, hydroxyl and hydropemxyl. The hydrogen peroxide solution is impinged upon a heated surface in a stream of nitric oxide where it decomposes to produce the oxidative free radicals. Because the decomposition of the hydrogen peroxide solution occurs within the stream of the nitric oxide, rapid gas-phase oxidation of nitric oxide into nitrogen dioxide occurs.

  10. Kinetics and mechanism of the oxidation of alkenes and silanes by hydrogen peroxide catalyzed by methylrhenium trioxide (MTO) and a novel application of electrospray mass spectrometry to study the hydrolysis of MTO

    SciTech Connect

    Tan, Haisong

    1999-11-08

    Conjugated dienes were oxidized by hydrogen peroxide with methylrhenium trioxide (MTO) as catalyst. Methylrhenium bis-peroxide was the major reactive catalyst present. Hydroxyalkenes and trisubstituted silane were also tested. Mechanisms for each of these reactions are presented.

  11. Spectroscopic and Kinetic Evidence for the Crucial Role of Compound 0 in the P450cam -Catalyzed Hydroxylation of Camphor by Hydrogen Peroxide.

    PubMed

    Franke, Alicja; van Eldik, Rudi

    2015-10-19

    The hydroperoxo iron(III) intermediate P450cam Fe(III) -OOH, being the true Compound 0 (Cpd 0) involved in the natural catalytic cycle of P450cam , could be transiently observed in the peroxo-shunt oxidation of the substrate-free enzyme by hydrogen peroxide under mild basic conditions and low temperature. The prolonged lifetime of Cpd 0 enabled us to kinetically examine the formation and reactivity of P450cam Fe(III) -OOH species as a function of varying reaction conditions, such as pH, and concentration of H2 O2 , camphor, and potassium ions. The mechanism of hydrogen peroxide binding to the substrate-free form of P450cam differs completely from that observed for other heme proteins possessing the distal histidine as a general acid-base catalyst and is mainly governed by the ability of H2 O2 to undergo deprotonation at the hydroxo ligand coordinated to the iron(III) center under conditions of pH≥p${K{{{\\rm P450}\\hfill \\atop {\\rm a}\\hfill}}}$. Notably, no spectroscopic evidence for the formation of either Cpd I or Cpd II as products of heterolytic or homolytic OO bond cleavage, respectively, in Cpd 0 could be observed under the selected reaction conditions. The kinetic data obtained from the reactivity studies involving (1R)-camphor, provide, for the first time, experimental evidence for the catalytic activity of the P450Fe(III) -OOH intermediate in the oxidation of the natural substrate of P450cam . © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  12. Improving the hydrogen peroxide bleaching efficiency of aspen chemithermomechanical pulp by using chitosan.

    PubMed

    Li, Zongquan; Dou, Hongyan; Fu, Yingjuan; Qin, Menghua

    2015-11-05

    The presence of transition metals during the hydrogen peroxide bleaching of pulp results in the decomposition of hydrogen peroxide, which decreases the bleaching efficiency. In this study, chitosans were used as peroxide stabilizer in the alkaline hydrogen peroxide bleaching of aspen chemithermomechanical pulp (CTMP). The results showed that the brightness of the bleached CTMP increased 1.5% ISO by addition of 0.1% chitosan with 95% degree of deacetylation during peroxide bleaching. Transition metals in the form of ions or metal colloid particles, such as iron, copper and manganese, could be adsorbed by chitosans. Chitosans could inhibit the decomposition of hydrogen peroxide catalyzed by different transition metals under alkaline conditions. The ability of chitosans to inhibit peroxide decomposition depended on the type of transition metals, chitosan concentration and degree of deacetylation applied. The addition of chitosan slightly reduced the concentration of the hydroxyl radical formed during the hydrogen peroxide bleaching of aspen CTMP. Copyright © 2015 Elsevier Ltd. All rights reserved.

  13. Molecular Association and Structure of Hydrogen Peroxide.

    ERIC Educational Resources Information Center

    Giguere, Paul A.

    1983-01-01

    The statement is sometimes made in textbooks that liquid hydrogen peroxide is more strongly associated than water, evidenced by its higher boiling point and greater heat of vaporization. Discusses these and an additional factor (the nearly double molecular mass of the peroxide), focusing on hydrogen bonds and structure of the molecule. (JN)

  14. 7 CFR 58.431 - Hydrogen peroxide.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 3 2010-01-01 2010-01-01 false Hydrogen peroxide. 58.431 Section 58.431 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (Standards... Material § 58.431 Hydrogen peroxide. The solution shall comply with the specification of the...

  15. 7 CFR 58.431 - Hydrogen peroxide.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 7 Agriculture 3 2011-01-01 2011-01-01 false Hydrogen peroxide. 58.431 Section 58.431 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (Standards... Material § 58.431 Hydrogen peroxide. The solution shall comply with the specification of the...

  16. 7 CFR 58.431 - Hydrogen peroxide.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 7 Agriculture 3 2014-01-01 2014-01-01 false Hydrogen peroxide. 58.431 Section 58.431 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (Standards... Material § 58.431 Hydrogen peroxide. The solution shall comply with the specification of the U.S...

  17. 7 CFR 58.431 - Hydrogen peroxide.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 7 Agriculture 3 2013-01-01 2013-01-01 false Hydrogen peroxide. 58.431 Section 58.431 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (Standards... Material § 58.431 Hydrogen peroxide. The solution shall comply with the specification of the U.S...

  18. Molecular Association and Structure of Hydrogen Peroxide.

    ERIC Educational Resources Information Center

    Giguere, Paul A.

    1983-01-01

    The statement is sometimes made in textbooks that liquid hydrogen peroxide is more strongly associated than water, evidenced by its higher boiling point and greater heat of vaporization. Discusses these and an additional factor (the nearly double molecular mass of the peroxide), focusing on hydrogen bonds and structure of the molecule. (JN)

  19. 7 CFR 58.431 - Hydrogen peroxide.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 7 Agriculture 3 2012-01-01 2012-01-01 false Hydrogen peroxide. 58.431 Section 58.431 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (Standards... Material § 58.431 Hydrogen peroxide. The solution shall comply with the specification of the U.S...

  20. Fundamentals of ISCO Using Hydrogen Peroxide

    EPA Science Inventory

    Hydrogen peroxide is a common oxidant that has been applied extensively with in situ chemical oxidation (ISCO). Because of its widespread use in this and other fields, it has been extensively researched. This research has revealed that hydrogen peroxide has very complex chemistry...

  1. Fundamentals of ISCO Using Hydrogen Peroxide

    EPA Science Inventory

    Hydrogen peroxide is a common oxidant that has been applied extensively with in situ chemical oxidation (ISCO). Because of its widespread use in this and other fields, it has been extensively researched. This research has revealed that hydrogen peroxide has very complex chemistry...

  2. Vapor Hydrogen Peroxide Sterilization Certification

    NASA Astrophysics Data System (ADS)

    Chen, Fei; Chung, Shirley; Barengoltz, Jack

    For interplanetary missions landing on a planet of potential biological interest, United States NASA planetary protection currently requires that the flight system must be assembled, tested and ultimately launched with the intent of minimizing the bioload taken to and deposited on the planet. Currently the only NASA approved microbial reduction method is dry heat sterilization process. However, with utilization of such elements as highly sophisticated electronics and sensors in modern spacecraft, this process presents significant materials challenges and is thus an undesirable bioburden reduction method to design engineers. The objective of this work is to introduce vapor hydrogen peroxide (VHP) as an alternative to dry heat microbial reduction to meet planetary protection requirements. The VHP sterilization technology is widely used by the medical industry, but high doses of VHP may degrade the performance of flight hardware, or compromise material compatibility. The goal of our study is determine the minimum VHP process conditions for PP acceptable microbial reduction levels. A series of experiments were conducted using Geobacillus stearothermophilus to determine VHP process parameters that provided significant reductions in spore viability while allowing survival of sufficient spores for statistically significant enumeration. In addition to the obvious process parameters -hydrogen peroxide concentration, number of pulses, and exposure duration -the investigation also considered the possible effect of environmental pa-rameters. Temperature, relative humidity, and material substrate effects on lethality were also studied. Based on the results, a most conservative D value was recommended. This recom-mended D value was also validated using VHP "hardy" strains that were isolated from clean-rooms and environmental populations collected from spacecraft relevant areas. The efficiency of VHP at ambient condition as well as VHP material compatibility will also be

  3. Kinetics and mechanisms of the oxidation of alcohols and hydroxylamines by hydrogen peroxide, catalyzed by methyltrioxorhenium, MTO, and the oxygen binding properties of cobalt Schiff base complexes

    SciTech Connect

    Zauche, Timothy

    1999-02-12

    Catalysis is a very interesting area of chemistry, which is currently developing at a rapid pace. A great deal of effort is being put forth by both industry and academia to make reactions faster and more productive. One method of accomplishing this is by the development of catalysts. Enzymes are an example of catalysts that are able to perform reactions on a very rapid time scale and also very specifically; a goal for every man-made catalyst. A kinetic study can also be carried out for a reaction to gain a better understanding of its mechanism and to determine what type of catalyst would assist the reaction. Kinetic studies can also help determine other factors, such as the shelf life of a chemical, or the optimum temperature for an industrial scale reaction. An area of catalysis being studied at this time is that of oxygenations. Life on this earth depends on the kinetic barriers for oxygen in its various forms. If it were not for these barriers, molecular oxygen, water, and the oxygenated materials in the land would be in a constant equilibrium. These same barriers must be overcome when performing oxygenation reactions on the laboratory or industrial scale. By performing kinetic studies and developing catalysts for these reactions, a large number of reactions can be made more economical, while making less unwanted byproducts. For this dissertation the activation by transition metal complexes of hydrogen peroxide or molecular oxygen coordination will be discussed.

  4. Detection of hydrogen peroxide with chemiluminescent micelles

    PubMed Central

    Lee, Dongwon; Erigala, Venkata R; Dasari, Madhuri; Yu, Junhua; Dickson, Robert M; Murthy, Niren

    2008-01-01

    The overproduction of hydrogen peroxide is implicated in the progress of numerous life-threatening diseases and there is a great need for the development of contrast agents that can detect hydrogen peroxide in vivo. In this communication, we present a new contrast agent for hydrogen peroxide, termed peroxalate micelles, which detect hydrogen peroxide through chemiluminescence, and have the physical/chemical properties needed for in vivo imaging applications. The peroxalate micelles are composed of amphiphilic peroxalate based copolymers and the fluorescent dye rubrene, they have a ‘stealth’ polyethylene glycol (PEG) corona to evade macrophage phagocytosis, and a diameter of 33 nm to enhance extravasation into permeable tissues. The peroxalate micelles can detect nanomolar concentrations of hydrogen peroxide (>50 nM) and thus have the sensitivity needed to detect physiological concentrations of hydrogen peroxide. We anticipate numerous applications of the peroxalate micelles for in vivo imaging of hydrogen peroxide, given their high sensitivity, small size, and biocompatible PEG corona. PMID:19337415

  5. High temperature decomposition of hydrogen peroxide

    NASA Technical Reports Server (NTRS)

    Parrish, Clyde F. (Inventor)

    2004-01-01

    Nitric oxide (NO) is oxidized into nitrogen dioxide (NO.sub.2) by the high temperature decomposition of a hydrogen peroxide solution to produce the oxidative free radicals, hydroxyl and hydroperoxyl. The hydrogen peroxide solution is impinged upon a heated surface in a stream of nitric oxide where it decomposes to produce the oxidative free radicals. Because the decomposition of the hydrogen peroxide solution occurs within the stream of the nitric oxide, rapid gas-phase oxidation of nitric oxide into nitrogen dioxide occurs.

  6. High temperature decomposition of hydrogen peroxide

    NASA Technical Reports Server (NTRS)

    Parrish, Clyde F. (Inventor)

    2011-01-01

    Nitric oxide (NO) is oxidized into nitrogen dioxide (NO.sub.2) by the high temperature decomposition of a hydrogen peroxide solution to produce the oxidative free radicals, hydroxyl and hydroperoxyl. The hydrogen peroxide solution is impinged upon a heated surface in a stream of nitric oxide where it decomposes to produce the oxidative free radicals. Because the decomposition of the hydrogen peroxide solution occurs within the stream of the nitric oxide, rapid gas-phase oxidation of nitric oxide into nitrogen dioxide occurs.

  7. Microcalorimetric Measurements of Hydrogen Peroxide Stability

    NASA Technical Reports Server (NTRS)

    Davis, Dennis D.; Hornung, Steven D.; Baker, Dave L.

    1999-01-01

    Recent interest in propellants with nontoxic reaction products has led to a resurgence of interest in hydrogen peroxide for various propellant applications. Because hydrogen peroxide is sensitive to contaminants and materials interactions, stability and shelf life are issues. A relatively new, ultrasensitive heat measurement technique, isothermal microcalorimetry, is being used at the White Sands Test Facility to monitor the decomposition of hydrogen peroxide at near ambient temperatures. Isothermal microcalorimetry measures the beat flow from a reaction vessel into a surrounding heat sink. In these applications, microcalorimetry is approximately 1,000 times more sensitive than accelerating rate calorimetry or differential scanning calorimetry for measuring thermal events. Experimental procedures have been developed for the microcalorimetric measurement of the ultra-small beat effects caused by incompatible interactions of hydrogen peroxide. The decomposition rates of hydrogen peroxide at the picomole/sec/gram level have been measured showing the effects of stabilizers and peroxide concentration. Typical measurements are carried out at 40 C over a 24-hour period, This paper describes a method for the conversion of the heat flow measurements to chemical reaction rates based on thermochemical considerations. The reaction rates are used in a study of the effects of stabilizer levels on the decomposition of propellant grade hydrogen peroxide.

  8. Microcalorimetric Measurements of Hydrogen Peroxide Stability

    NASA Technical Reports Server (NTRS)

    Davis, Dennis D.; Hornung, Steven D.; Baker, Dave L.

    1999-01-01

    Recent interest in propellants with nontoxic reaction products has led to a resurgence of interest in hydrogen peroxide for various propellant applications. Because hydrogen peroxide is sensitive to contaminants and materials interactions, stability and shelf life are issues. A relatively new, ultrasensitive heat measurement technique, isothermal microcalorimetry, is being used at the White Sands Test Facility to monitor the decomposition of hydrogen peroxide at near ambient temperatures. Isothermal microcalorimetry measures the beat flow from a reaction vessel into a surrounding heat sink. In these applications, microcalorimetry is approximately 1,000 times more sensitive than accelerating rate calorimetry or differential scanning calorimetry for measuring thermal events. Experimental procedures have been developed for the microcalorimetric measurement of the ultra-small beat effects caused by incompatible interactions of hydrogen peroxide. The decomposition rates of hydrogen peroxide at the picomole/sec/gram level have been measured showing the effects of stabilizers and peroxide concentration. Typical measurements are carried out at 40 C over a 24-hour period, This paper describes a method for the conversion of the heat flow measurements to chemical reaction rates based on thermochemical considerations. The reaction rates are used in a study of the effects of stabilizer levels on the decomposition of propellant grade hydrogen peroxide.

  9. [Hydrogen peroxide in the troposphere].

    PubMed

    Pehnec, Gordana

    2007-06-01

    The past few decades saw a rising interest in the role of hydrogen peroxide (H2O2) in atmospheric chemistry and its contribution to the formation of free radicals. Free radicals (oxidants) are formed by photochemical reactions between ozone and H2O2. Free radicals formed within cells can oxidise biomolecules, and this may lead to cell death and tissue injury. For this reason, free radicals are believed to cause more than 100 diseases. H2O2 has been suggested as a better indicator of atmospheric oxidation capacity than ozone. Atmospheric H2O2 can appear in the gas phase or in the aqueous phase. It shows typical diurnal and seasonal variations. However, measurements of H2O2 with expensive and sophisticated equipment are rare and limited to but a few sites in the world. Measurements in Greenland ice cores showed that H2O2 concentrations increased over the last 200 years and most of the increase has occurred over the last 20 years. Evaluations show that concentrations will still rise as a result of decreasing SO2 emission. H2O2 measurements have not been carried out in Croatia until now, and, accompanied by the existing longterm measurements of ozone and nitrogen oxides, they will provide an idea of the oxidative capacity of the atmosphere and its influence on oxidative stress.

  10. Hydrogen peroxide treatment of TCE contaminated soil

    SciTech Connect

    Hurst, D.H.; Robinson, K.G.; Siegrist, R.L.

    1993-12-31

    Solvent contaminated soils are ubiquitous in the industrial world and represent a significant environmental hazard due to their persistence and potentially negative impacts on human health and the environment. Environmental regulations favor treatment of soils with options which reduce the volume and toxicity of contaminants in place. One such treatment option is the in-situ application of hydrogen peroxide to soils contaminated with chlorinated solvents such as trichloroethylene (TCE). This study investigated hydrogen peroxide mass loading rates on removal of TCE from soils of varying organic matter content. Batch experiments conducted on contaminated loam samples using GC headspace analysis showed up to 80% TCE removal upon peroxide treatment. Column experiments conducted on sandy loam soils with high organic matter content showed only 25% TCE removal, even at hydrogen peroxide additions of 25 g peroxide per kg soil.

  11. Hydrogen Peroxide-Resistant CotA and YjqC of Bacillus altitudinis Spores Are a Promising Biocatalyst for Catalyzing Reduction of Sinapic Acid and Sinapine in Rapeseed Meal

    PubMed Central

    Zhang, Yanzhou; Li, Xunhang; Hao, Zhikui; Xi, Ruchun; Cai, Yujie; Liao, Xiangru

    2016-01-01

    For the more efficient detoxification of phenolic compounds, a promising avenue would be to develop a multi-enzyme biocatalyst comprising peroxidase, laccase and other oxidases. However, the development of this multi-enzyme biocatalyst is limited by the vulnerability of fungal laccases and peroxidases to hydrogen peroxide (H2O2)-induced inactivation. Therefore, H2O2-resistant peroxidase and laccase should be exploited. In this study, H2O2-stable CotA and YjqC were isolated from the outer coat of Bacillus altitudinis SYBC hb4 spores. In addition to the thermal and alkali stability of catalytic activity, CotA also exhibited a much higher H2O2 tolerance than fungal laccases from Trametes versicolor and Trametes trogii. YjqC is a sporulation-related manganese (Mn) catalase with striking peroxidase activity for sinapic acid (SA) and sinapine (SNP). In contrast to the typical heme-containing peroxidases, the peroxidase activity of YjqC was also highly resistant to inhibition by H2O2 and heat. CotA could also catalyze the oxidation of SA and SNP. CotA had a much higher affinity for SA than B. subtilis CotA. CotA and YjqC rendered from B. altitudinis spores had promising laccase and peroxidase activities for SA and SNP. Specifically, the B. altitudinis spores could be regarded as a multi-enzyme biocatalyst composed of CotA and YjqC. The B. altitudinis spores were efficient for catalyzing the degradation of SA and SNP in rapeseed meal. Moreover, efficiency of the spore-catalyzed degradation of SA and SNP was greatly improved by the presence of 15 mM H2O2. This effect was largely attributed to synergistic biocatalysis of the H2O2-resistant CotA and YjqC toward SA and SNP. PMID:27362423

  12. Hydrogen Peroxide as a Sustainable Energy Carrier: Electrocatalytic Production of Hydrogen Peroxide and the Fuel Cell.

    PubMed

    Fukuzumi, Shunichi; Yamada, Yusuke; Karlin, Kenneth D

    2012-11-01

    This review describes homogeneous and heterogeneous catalytic reduction of dioxygen with metal complexes focusing on the catalytic two-electron reduction of dioxygen to produce hydrogen peroxide. Whether two-electron reduction of dioxygen to produce hydrogen peroxide or four-electron O2-reduction to produce water occurs depends on the types of metals and ligands that are utilized. Those factors controlling the two processes are discussed in terms of metal-oxygen intermediates involved in the catalysis. Metal complexes acting as catalysts for selective two-electron reduction of oxygen can be utilized as metal complex-modified electrodes in the electrocatalytic reduction to produce hydrogen peroxide. Hydrogen peroxide thus produced can be used as a fuel in a hydrogen peroxide fuel cell. A hydrogen peroxide fuel cell can be operated with a one-compartment structure without a membrane, which is certainly more promising for the development of low-cost fuel cells as compared with two compartment hydrogen fuel cells that require membranes. Hydrogen peroxide is regarded as an environmentally benign energy carrier because it can be produced by the electrocatalytic two-electron reduction of O2, which is abundant in air, using solar cells; the hydrogen peroxide thus produced could then be readily stored and then used as needed to generate electricity through the use of hydrogen peroxide fuel cells.

  13. Hydrogen Peroxide as a Sustainable Energy Carrier: Electrocatalytic Production of Hydrogen Peroxide and the Fuel Cell

    PubMed Central

    Fukuzumi, Shunichi; Yamada, Yusuke; Karlin, Kenneth D.

    2012-01-01

    This review describes homogeneous and heterogeneous catalytic reduction of dioxygen with metal complexes focusing on the catalytic two-electron reduction of dioxygen to produce hydrogen peroxide. Whether two-electron reduction of dioxygen to produce hydrogen peroxide or four-electron O2-reduction to produce water occurs depends on the types of metals and ligands that are utilized. Those factors controlling the two processes are discussed in terms of metal-oxygen intermediates involved in the catalysis. Metal complexes acting as catalysts for selective two-electron reduction of oxygen can be utilized as metal complex-modified electrodes in the electrocatalytic reduction to produce hydrogen peroxide. Hydrogen peroxide thus produced can be used as a fuel in a hydrogen peroxide fuel cell. A hydrogen peroxide fuel cell can be operated with a one-compartment structure without a membrane, which is certainly more promising for the development of low-cost fuel cells as compared with two compartment hydrogen fuel cells that require membranes. Hydrogen peroxide is regarded as an environmentally benign energy carrier because it can be produced by the electrocatalytic two-electron reduction of O2, which is abundant in air, using solar cells; the hydrogen peroxide thus produced could then be readily stored and then used as needed to generate electricity through the use of hydrogen peroxide fuel cells. PMID:23457415

  14. NASA Hydrogen Peroxide Propellant Hazards Technical Manual

    NASA Technical Reports Server (NTRS)

    Baker, David L.; Greene, Ben; Frazier, Wayne

    2005-01-01

    The Fire, Explosion, Compatibility and Safety Hazards of Hydrogen Peroxide NASA technical manual was developed at the NASA Johnson Space Center White Sands Test Facility. NASA Technical Memorandum TM-2004-213151 covers topics concerning high concentration hydrogen peroxide including fire and explosion hazards, material and fluid reactivity, materials selection information, personnel and environmental hazards, physical and chemical properties, analytical spectroscopy, specifications, analytical methods, and material compatibility data. A summary of hydrogen peroxide-related accidents, incidents, dose calls, mishaps and lessons learned is included. The manual draws from art extensive literature base and includes recent applicable regulatory compliance documentation. The manual may be obtained by United States government agencies from NASA Johnson Space Center and used as a reference source for hazards and safe handling of hydrogen peroxide.

  15. Isothermal Decomposition of Hydrogen Peroxide Dihydrate

    NASA Technical Reports Server (NTRS)

    Loeffler, M. J.; Baragiola, R. A.

    2011-01-01

    We present a new method of growing pure solid hydrogen peroxide in an ultra high vacuum environment and apply it to determine thermal stability of the dihydrate compound that forms when water and hydrogen peroxide are mixed at low temperatures. Using infrared spectroscopy and thermogravimetric analysis, we quantified the isothermal decomposition of the metastable dihydrate at 151.6 K. This decomposition occurs by fractional distillation through the preferential sublimation of water, which leads to the formation of pure hydrogen peroxide. The results imply that in an astronomical environment where condensed mixtures of H2O2 and H2O are shielded from radiolytic decomposition and warmed to temperatures where sublimation is significant, highly concentrated or even pure hydrogen peroxide may form.

  16. Isothermal Decomposition of Hydrogen Peroxide Dihydrate

    NASA Technical Reports Server (NTRS)

    Loeffler, M. J.; Baragiola, R. A.

    2011-01-01

    We present a new method of growing pure solid hydrogen peroxide in an ultra high vacuum environment and apply it to determine thermal stability of the dihydrate compound that forms when water and hydrogen peroxide are mixed at low temperatures. Using infrared spectroscopy and thermogravimetric analysis, we quantified the isothermal decomposition of the metastable dihydrate at 151.6 K. This decomposition occurs by fractional distillation through the preferential sublimation of water, which leads to the formation of pure hydrogen peroxide. The results imply that in an astronomical environment where condensed mixtures of H2O2 and H2O are shielded from radiolytic decomposition and warmed to temperatures where sublimation is significant, highly concentrated or even pure hydrogen peroxide may form.

  17. Isothermal decomposition of hydrogen peroxide dihydrate.

    PubMed

    Loeffler, M J; Baragiola, R A

    2011-06-02

    We present a new method of growing pure solid hydrogen peroxide in an ultra high vacuum environment and apply it to determine thermal stability of the dihydrate compound that forms when water and hydrogen peroxide are mixed at low temperatures. Using infrared spectroscopy and thermogravimetric analysis, we quantified the isothermal decomposition of the metastable dihydrate at 151.6 K. This decomposition occurs by fractional distillation through the preferential sublimation of water, which leads to the formation of pure hydrogen peroxide. The results imply that in an astronomical environment where condensed mixtures of H(2)O(2) and H(2)O are shielded from radiolytic decomposition and warmed to temperatures where sublimation is significant, highly concentrated or even pure hydrogen peroxide may form. © 2011 American Chemical Society

  18. Ultraviolet absorption cross sections of hydrogen peroxide

    NASA Technical Reports Server (NTRS)

    Lin, C. L.; Rohatgi, N. K.; Demore, W. B.

    1978-01-01

    Absorption cross-sections of hydrogen peroxide vapor and of neutral aqueous solutions of hydrogen peroxide were measured in the wavelength range from 195 to 350 nm at 296 K. The spectrophotometric procedure is described, and the reported cross-sections are compared with values obtained by other researchers. Photodissociation coefficients of atmospheric H2O2 were calculated for direct absorption of unscattered solar radiation, and the vertical distributions of these coefficients are shown for various solar zenith angles.

  19. 21 CFR 178.1005 - Hydrogen peroxide solution.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 3 2014-04-01 2014-04-01 false Hydrogen peroxide solution. 178.1005 Section 178... Growth of Microorganisms § 178.1005 Hydrogen peroxide solution. Hydrogen peroxide solution identified in...)(1) of this section. (a) Identity. For the purpose of this section, hydrogen peroxide solution is an...

  20. Process for the production of hydrogen peroxide

    DOEpatents

    Datta, R.; Randhava, S.S.; Tsai, S.P.

    1997-09-02

    An integrated membrane-based process method for producing hydrogen peroxide is provided comprising oxidizing hydrogenated anthraquinones with air bubbles which were created with a porous membrane, and then contacting the oxidized solution with a hydrophilic membrane to produce an organics free, H{sub 2}O{sub 2} laden permeate. 1 fig.

  1. Process for the production of hydrogen peroxide

    DOEpatents

    Datta, Rathin; Randhava, Sarabjit S.; Tsai, Shih-Perng

    1997-01-01

    An integrated membrane-based process method for producing hydrogen peroxide is provided comprising oxidizing hydrogenated anthraquinones with air bubbles which were created with a porous membrane, and then contacting the oxidized solution with a hydrophilic membrane to produce an organics free, H.sub.2 O.sub.2 laden permeate.

  2. 21 CFR 173.356 - Hydrogen peroxide.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 3 2014-04-01 2014-04-01 false Hydrogen peroxide. 173.356 Section 173.356 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) SECONDARY DIRECT FOOD ADDITIVES PERMITTED IN FOOD FOR HUMAN CONSUMPTION Specific Usage Additives § 173.356 Hydrogen...

  3. [Hydrogen peroxide in artificial photosynthesizing systems].

    PubMed

    Lobanov, A V; Komissarov, G G

    2014-01-01

    From the point of view of the concepts of hydrogen peroxide as a source of photosynthetic oxygen (hydrogen) coordination and photochemical properties of chlorophyll and its aggregates towards hydrogen peroxide were considered. The binding energy of H2O and H2O2 with chlorophyll and chlorophyllide depending on their form (monomers, dimers and trimers) was estimated by quantum chemical calculations. It is shown that at an increase of the degree of the pigment aggregation binding energy of H2O2 was more than the energy of H2O. Analysis of experimental results of the photochemical decomposition of hydrogen peroxide using chlorophyll was carried out. Estimates of the thermodynamic parameters (deltaG degrees and deltaH degrees) of the formation of organic compounds from CO2 with water and hydrogen peroxide were compared. The interaction of CO2 with H2O2 requires much less energy consumption than with water for all considered cases. The formation of organic products (formaldehyde, alcohols, carboxylic and carbonylic compounds) and simultaneous production of O2 under the influence of visible light in the systems of inorganic carbon--hydrogen peroxide--chlorophyll (phthalocyanine) is detected by GC/MS method, FTIR spectroscopy, and chemical analysis.

  4. Direct, efficient, and inexpensive formation of alpha-hydroxyketones from olefins by hydrogen peroxide oxidation catalyzed by the 12-tungstophosphoric acid/cetylpyridinium chloride system.

    PubMed

    Zhang, Yanfei; Shen, Zongxuan; Tang, Jingting; Zhang, Yan; Kong, Lichun; Zhang, Yawen

    2006-04-21

    The direct ketohydroxylation of a variety of 1-aryl-1-alkenes with H2O2, catalyzed by the inexpensive 12-tungstophosphoric acid/cetylpyridinium chloride system under very mild conditions, was achieved. Various acyloins were obtained in good yields and high regioselectivies.

  5. In vivo imaging of hydrogen peroxide with chemiluminescent nanoparticles.

    PubMed

    Lee, Dongwon; Khaja, Sirajud; Velasquez-Castano, Juan C; Dasari, Madhuri; Sun, Carrie; Petros, John; Taylor, W Robert; Murthy, Niren

    2007-10-01

    The overproduction of hydrogen peroxide is implicated in the development of numerous diseases and there is currently great interest in developing contrast agents that can image hydrogen peroxide in vivo. In this report, we demonstrate that nanoparticles formulated from peroxalate esters and fluorescent dyes can image hydrogen peroxide in vivo with high specificity and sensitivity. The peroxalate nanoparticles image hydrogen peroxide by undergoing a three-component chemiluminescent reaction between hydrogen peroxide, peroxalate esters and fluorescent dyes. The peroxalate nanoparticles have several attractive properties for in vivo imaging, such as tunable wavelength emission (460-630 nm), nanomolar sensitivity for hydrogen peroxide and excellent specificity for hydrogen peroxide over other reactive oxygen species. The peroxalate nanoparticles were capable of imaging hydrogen peroxide in the peritoneal cavity of mice during a lipopolysaccharide-induced inflammatory response. We anticipate numerous applications of peroxalate nanoparticles for in vivo imaging of hydrogen peroxide, given their high specificity and sensitivity and deep-tissue-imaging capability.

  6. Catalyst Development for Hydrogen Peroxide Rocket Engines

    NASA Technical Reports Server (NTRS)

    Morlan, P. W.; Wu, P.-K.; Ruttle, D. W.; Fuller, R. P.; Nejad, A. S.; Anderson, W. E.

    1999-01-01

    The development of various catalysts of hydrogen peroxide was conducted for the applications of liquid rocket engines. The catalyst development includes silver screen technology, solid catalyst technology, and homogeneous catalyst technology. The silver screen technology development was performed with 85% (by weight) hydrogen peroxide. The results of this investigation were used as the basis for the catalyst design of a pressure-fed liquid-fueled upper stage engine. Both silver-plated nickel 200 screens and pure silver screens were used as the active metal catalyst during the investigation, The data indicate that a high decomposition efficiency (greater than 90%) of 85% hydrogen peroxide can be achieved at a bed loading of 0.5 lbm/sq in/sec with both pure silver and silver plated screens. Samarium oxide coating, however, was found to retard the decomposition process and the catalyst bed was flooded at lower bed loading. A throughput of 200 lbm of hydrogen peroxide (1000 second run time) was tested to evaluate the catalyst aging issue and performance degradation was observed starting at approximately 400 seconds. Catalyst beds of 3.5 inch in diameter was fabricated using the same configuration for a 1,000-lbf rocket engine. High decomposition efficiency was obtained with a low pressure drop across the bed. Solid catalyst using precious metal was also developed for the decomposition of hydrogen peroxide from 85% to 98% by weight. Preliminary results show that the catalyst has a strong reactivity even after 15 minutes of peroxide decomposition. The development effort also includes the homogeneous catalyst technology. Various non-toxic catalysts were evaluated with 98% peroxide and hydrocarbon fuels. The results of open cup drop tests indicate an ignition delay around 11 ms.

  7. Catalyst Development for Hydrogen Peroxide Rocket Engines

    NASA Technical Reports Server (NTRS)

    Morlan, P. W.; Wu, P.-K.; Ruttle, D. W.; Fuller, R. P.; Nejad, A. S.; Anderson, W. E.

    1999-01-01

    The development of various catalysts of hydrogen peroxide was conducted for the applications of liquid rocket engines. The catalyst development includes silver screen technology, solid catalyst technology, and homogeneous catalyst technology. The silver screen technology development was performed with 85% (by weight) hydrogen peroxide. The results of this investigation were used as the basis for the catalyst design of a pressure-fed liquid-fueled upper stage engine. Both silver-plated nickel 200 screens and pure silver screens were used as the active metal catalyst during the investigation, The data indicate that a high decomposition efficiency (greater than 90%) of 85% hydrogen peroxide can be achieved at a bed loading of 0.5 lbm/sq in/sec with both pure silver and silver plated screens. Samarium oxide coating, however, was found to retard the decomposition process and the catalyst bed was flooded at lower bed loading. A throughput of 200 lbm of hydrogen peroxide (1000 second run time) was tested to evaluate the catalyst aging issue and performance degradation was observed starting at approximately 400 seconds. Catalyst beds of 3.5 inch in diameter was fabricated using the same configuration for a 1,000-lbf rocket engine. High decomposition efficiency was obtained with a low pressure drop across the bed. Solid catalyst using precious metal was also developed for the decomposition of hydrogen peroxide from 85% to 98% by weight. Preliminary results show that the catalyst has a strong reactivity even after 15 minutes of peroxide decomposition. The development effort also includes the homogeneous catalyst technology. Various non-toxic catalysts were evaluated with 98% peroxide and hydrocarbon fuels. The results of open cup drop tests indicate an ignition delay around 11 ms.

  8. Mechanism of toxicity of hydrogen peroxide

    SciTech Connect

    Imlay, J.A.

    1987-01-01

    We examined the capacity of hydrogen peroxide to injure E. coli. Externally applied hydrogen peroxide rapidly permeates the bacterial cell and causes at least two classes of potentially lethal damage. These classes were initially distinguished by the kinetics of their production. Additional distinctions have been made regarding the chemistry of cell injury and the details of the cell response. One class of cell damage consists of DNA lesions; if unrepaired, mode one killing results. Hydrogen peroxide does not directly attack the DNA. Instead, ferrous iron reduces the peroxide to generate a hydroxyl-radical-like species, which acts as a DNA oxidant. The peculiar kinetics of mode-one killing may reflect an high reaction rate between this radical and peroxide itself. Interestingly, NADH may chemically reduce ferric iron in order to start and maintain the sequence of redox reactions. The target of the other class of cell damage is unknown. This damage, unlike that associated with mode-one killing, does not rely upon Fenton chemistry. Scavenging enzymes, such as catalase and superoxide dismutase, contribute to resisting oxidative stress. Increases in catalase titer accelerate detoxification of peroxide and are responsible for the protective effects of oxyR induction. When oxidants elude this defense and nick DNA, a variety of enzymes-exonuclease III, endonuclease IV, and DNA polymerase I-repair the damage.

  9. Hydrogen Peroxide - Material Compatibility Studied by Microcalorimetry

    NASA Technical Reports Server (NTRS)

    Homung, Steven D.; Davis, Dennis D.; Baker, David; Popp, Christopher G.

    2003-01-01

    Environmental and toxicity concerns with current hypergolic propellants have led to a renewed interest in propellant grade hydrogen peroxide (HP) for propellant applications. Storability and stability has always been an issue with HP. Contamination or contact of HP with metallic surfaces may cause decomposition, which can result in the evolution of heat and gas leading to increased pressure or thermal hazards. The NASA Johnson Space Center White Sands Test Facility has developed a technique to monitor the decompositions of hydrogen peroxide at temperatures ranging from 25 to 60 C. Using isothermal microcalorimetry we have measured decomposition rates at the picomole/s/g level showing the catalytic effects of materials of construction. In this paper we will present the results of testing with Class 1 and 2 materials in 90 percent hydrogen peroxide.

  10. Lipoxygenase-catalyzed phospholipid peroxidation: preparation, purification, and characterization of phosphatidylinositol peroxides.

    PubMed

    O'Connor Butler, E Susan; Mazerik, Jessica N; Cruff, Jason P; Sherwani, Shariq I; Weis, Barbara K; Marsh, Clay B; Raghavamenon, Achuthan C; Uppu, Rao M; Schmid, Harald H O; Parinandi, Narasimham L

    2010-01-01

    The importance of understanding the mechanisms of modulation of cellular signaling cascades by the peroxidized membrane phospholipids (PLs) is well recognized. The enzyme-catalyzed peroxidation of PLs, as opposed to their oxidation by air and metal catalysis, is well controlled and rapid and yields well-defined PL peroxides which are highly desirable for biological studies. Therefore, here, we chose bovine liver phosphatidylinositol (PI), a crucial membrane PL which acts as the substrate for phospholipase C in cellular signal transduction, as a model membrane PL. We successfully generated the PI peroxides with soybean type-I lipoxygenase (LOX) in the presence of deoxycholate, which facilitates the LOX-mediated peroxidation of the polyunsaturated fatty acids esterified to the PL. The LOX-peroxidized PI, after enzymatic catalysis, was separated from the unoxidized PI in the reaction mixture by normal-phase, high-performance liquid chromatography (HPLC). The extent of LOX-mediated peroxidation of PI following HPLC purification was established by the analysis of lipid phosphorus, conjugated dienes by UV spectrophotometry, peroxides, and loss of fatty acids by gas chromatography. This study established the optimal conditions yielding approximately 46% of peroxidized PI from 300 microg of neat bovine liver PI that was peroxidized by soybean type-I LOX (50 microg) for 30 min in borate buffer (0.2 M, pH 9.0) containing 10 mM deoxycholate.

  11. The variation of hydrogen peroxide in rainwater over the South and Central Atlantic Ocean

    NASA Astrophysics Data System (ADS)

    Yuan, Jinchun; Shiller, Alan M.

    The concentration of hydrogen peroxide in rainwater over the South and Central Atlantic Ocean was determined. The rainwater samples were collected during an Intergovernmental Oceanographic Commission (IOC) sponsored baseline expedition in May and June 1996. The concentration of hydrogen peroxide was determined on diluted samples using a cobalt-catalyzed luminol chemiluminesence method. The concentration of hydrogen peroxide in rainwater varied from 3.5 to 71 μM with an average ( n=25) and standard deviation of 26 and 22 μM, respectively. These are similar to previously reported average hydrogen peroxide concentrations in marine rainwater of the Gulf of Mexico (40 μM), the western Atlantic Ocean (13 μM), and Florida Keys (28 μM). The concentration of hydrogen peroxide in rainwater varied with time of the day, with lower concentrations in early morning and higher concentrations in the late afternoon. The rainwater concentration of hydrogen peroxide also decreased during a rainstorm that may be an indication of a washout effect. The general levels of hydrogen peroxide in rainwater reported here and elsewhere together with the satellite-measured global distribution of precipitation indicate that wet deposition could affect water column hydrogen peroxide significantly in certain parts of the world.

  12. Occupational skin injury by hydrogen peroxide.

    PubMed

    Izu, K; Yamamoto, O; Asahi, M

    2000-01-01

    Hydrogen peroxide is widely used in products such as rocket fuel, bleaching preparations and topical disinfectants. Contact of hydrogen peroxide with the skin can cause severe skin damage. In this report, we describe a case of skin injury induced by hydrogen peroxide. The patient was a 34-year-old man working in a dry cleaning shop. While he was pouring 35% hydrogen peroxide, some of it accidentally splashed over his left shoulder and back, and then an erythema, purpura and vacuolar eruption, similar to bubble wrap, appeared on his left shoulder and down the left side of his back. Histologically, numerous vacuolar structures were observed in the epidermis, dermis and subcutaneous tissue. Coupled with the clinical features, these vacuolar structures were considered as 'oxygen bubbles'. Subcutaneous emphysema was detected by chest X-ray examination. All skin eruptions rapidly healed without scarring by using a steroid ointment. As far as we know, this is the first time such clinical and histological features have been described Copyright 2000 S. Karger AG, Basel.

  13. Systems and methods for generation of hydrogen peroxide vapor

    DOEpatents

    Love, Adam H; Eckels, Joel Del; Vu, Alexander K; Alcaraz, Armando; Reynolds, John G

    2014-12-02

    A system according to one embodiment includes a moisture trap for drying air; at least one of a first container and a second container; and a mechanism for at least one of: bubbling dried air from the moisture trap through a hydrogen peroxide solution in the first container for producing a hydrogen peroxide vapor, and passing dried air from the moisture trap into a headspace above a hydrogen peroxide solution in the second container for producing a hydrogen peroxide vapor. A method according one embodiment includes at least one of bubbling dried air through a hydrogen peroxide solution in a container for producing a first hydrogen peroxide vapor, and passing dried air from the moisture trap into a headspace above the hydrogen peroxide solution in a container for producing a second hydrogen peroxide vapor. Additional systems and methods are also presented.

  14. Efficacy, efficiency and safety aspects of hydrogen peroxide vapour and aerosolized hydrogen peroxide room disinfection systems.

    PubMed

    Fu, T Y; Gent, P; Kumar, V

    2012-03-01

    This was a head-to-head comparison of two hydrogen-peroxide-based room decontamination systems. To compare the efficacy, efficiency and safety of hydrogen peroxide vapour (HPV; Clarus R, Bioquell, Andover, U.K.) and aerosolized hydrogen peroxide (aHP; SR2, Sterinis, now supplied as Glosair, Advanced Sterilization Products (ASP), Johnson & Johnson Medical Ltd, Wokingham, U.K.) room disinfection systems. Efficacy was tested using 4- and 6-log Geobacillus stearothermophilus biological indicators (BIs) and in-house prepared test discs containing approximately 10(6) meticillin-resistant Staphylococcus aureus (MRSA), Clostridium difficile and Acinetobacter baumannii. Safety was assessed by detecting leakage of hydrogen peroxide using a hand-held detector. Efficiency was assessed by measuring the level of hydrogen peroxide using a hand-held sensor at three locations inside the room, 2 h after the start of the cycles. HPV generally achieved a 6-log reduction, whereas aHP generally achieved less than a 4-log reduction on the BIs and in-house prepared test discs. Uneven distribution was evident for the aHP system but not the HPV system. Hydrogen peroxide leakage during aHP cycles with the door unsealed, as per the manufacturer's operating manual, exceeded the short-term exposure limit (2 ppm) for more than 2 h. When the door was sealed with tape, as per the HPV system, hydrogen peroxide leakage was <1 ppm for both systems. The mean concentration of hydrogen peroxide in the room 2 h after the cycle started was 1.3 [standard deviation (SD) 0.4] ppm and 2.8 (SD 0.8) ppm for the four HPV and aHP cycles, respectively. None of the readings were <2 ppm for the aHP cycles. The HPV system was safer, faster and more effective for biological inactivation. Crown Copyright © 2012. Published by Elsevier Ltd. All rights reserved.

  15. An upper limit for stratospheric hydrogen peroxide

    NASA Technical Reports Server (NTRS)

    Chance, K. V.; Traub, W. A.

    1984-01-01

    It has been postulated that hydrogen peroxide is important in stratospheric chemistry as a reservoir and sink for odd hydrogen species, and for its ability to interconvert them. The present investigation is concerned with an altitude dependent upper limit curve for stratospheric hydrogen peroxide, taking into account an altitude range from 21.5 to 38.0 km for January 23, 1983. The data employed are from balloon flight No. 1316-P, launched from the National Scientific Balloon Facility (NSBF) in Palestine, Texas. The obtained upper limit curve lies substantially below the data reported by Waters et al. (1981), even though the results are from the same latitude and are both wintertime measurements.

  16. An upper limit for stratospheric hydrogen peroxide

    NASA Technical Reports Server (NTRS)

    Chance, K. V.; Traub, W. A.

    1984-01-01

    It has been postulated that hydrogen peroxide is important in stratospheric chemistry as a reservoir and sink for odd hydrogen species, and for its ability to interconvert them. The present investigation is concerned with an altitude dependent upper limit curve for stratospheric hydrogen peroxide, taking into account an altitude range from 21.5 to 38.0 km for January 23, 1983. The data employed are from balloon flight No. 1316-P, launched from the National Scientific Balloon Facility (NSBF) in Palestine, Texas. The obtained upper limit curve lies substantially below the data reported by Waters et al. (1981), even though the results are from the same latitude and are both wintertime measurements.

  17. 21 CFR 178.1005 - Hydrogen peroxide solution.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Hydrogen peroxide solution. 178.1005 Section 178... SANITIZERS Substances Utilized To Control the Growth of Microorganisms § 178.1005 Hydrogen peroxide solution. Hydrogen peroxide solution identified in this section may be safely used to sterilize polymeric...

  18. 21 CFR 178.1005 - Hydrogen peroxide solution.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 3 2011-04-01 2011-04-01 false Hydrogen peroxide solution. 178.1005 Section 178... SANITIZERS Substances Utilized To Control the Growth of Microorganisms § 178.1005 Hydrogen peroxide solution. Hydrogen peroxide solution identified in this section may be safely used to sterilize polymeric...

  19. 21 CFR 178.1005 - Hydrogen peroxide solution.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 3 2013-04-01 2013-04-01 false Hydrogen peroxide solution. 178.1005 Section 178... SANITIZERS Substances Utilized To Control the Growth of Microorganisms § 178.1005 Hydrogen peroxide solution. Hydrogen peroxide solution identified in this section may be safely used to sterilize polymeric food...

  20. 21 CFR 178.1005 - Hydrogen peroxide solution.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 3 2012-04-01 2012-04-01 false Hydrogen peroxide solution. 178.1005 Section 178... SANITIZERS Substances Utilized To Control the Growth of Microorganisms § 178.1005 Hydrogen peroxide solution. Hydrogen peroxide solution identified in this section may be safely used to sterilize polymeric food...

  1. Impact of hydrogen peroxide as a soil amendment on nasturtiums

    USDA-ARS?s Scientific Manuscript database

    Hydrogen peroxide, H2O2, is a highly reactive oxidizing agent naturally occurring in plants and animals. Plants produce hydrogen peroxide to destroy either their infected plant cells or the pathogens within their cells. Hydrogen peroxide also acts as a stress signal to plants. It is approved for c...

  2. Experimental investigation of hydrogen peroxide RF plasmas

    NASA Astrophysics Data System (ADS)

    Barni, R.; Decina, A.; Zanini, S.; D'Orazio, A.; Riccardi, C.

    2016-04-01

    This work reports a detailed experimental study of the plasma properties in low pressure RF discharges in hydrogen peroxide and a comparison with argon under the same operating conditions. H2O2 plasmas have been proposed for sterilization purposes. Electrical properties of the discharge were shown to be similar, as for the RF and DC voltages of the driving electrode. Bulk plasma volume remains stable, concentrated in an almost cylindrical region between the two facing electrodes. It was found that the electron temperature is almost uniform across the plasma and independent of the power level. This is higher than in argon discharges: T e  =  4.6  ±  0.9 eV versus T e  =  3.3  ±  1.1 eV. The plasma density increases almost linearly with the power level and a substantial negative ion component has been ruled out in hydrogen peroxide. Dissociation in the plasma gas phase was revealed by atomic hydrogen and hydroxyl radical emission in the discharge spectra. Emission from hydroxyl and atomic oxygen demonstrates that oxidizing radicals are produced by hydrogen peroxide discharges, revealing its usefulness for plasma processing other than sterilization, for instance to increase polymer film surface energy. On the other hand, argon could be considered as a candidate for the sterilization purposes due to the intense production of UV radiation.

  3. Catalyzed borohydrides for hydrogen storage

    DOEpatents

    Au, Ming [Augusta, GA

    2012-02-28

    A hydrogen storage material and process is provided in which alkali borohydride materials are created which contain effective amounts of catalyst(s) which include transition metal oxides, halides, and chlorides of titanium, zirconium, tin, and combinations of the various catalysts. When the catalysts are added to an alkali borodydride such as a lithium borohydride, the initial hydrogen release point of the resulting mixture is substantially lowered. Additionally, the hydrogen storage material may be rehydrided with weight percent values of hydrogen at least about 9 percent.

  4. Fluorometric determination of hydrogen peroxide in groundwater

    SciTech Connect

    Holm, T.R.; George, G.K.; Barcelona, M.J.

    1987-02-15

    The fluorometric scopoletin-horseradish peroxidase method has been modified for field determinations of hydrogen peroxide concentrations in groundwaters. Standard additions calibration compensates for background fluorescence and inconsistent stoichiometry of the fluorescence quenching reaction due to interferences by the matrix. The detection limit, defined as the blank plus three standard deviations, ranged from 3.6 to 44.6 nM. However, this limit was more an indication of the difficulty of preparing peroxide-free water than the actual limit imposed by the sensitivity of the method for the peroxide contamination introduced with the reagents. For 111 field determinations the weighted average (uncorrected) hydrogen peroxide concentration was 20.2 nM and the pooled standard deviation was 7.7 nM. The average of 45 field blanks was 7.8 nM with a pooled standard deviation of 5.2 nM. At nanomolar concentration levels, it is essential that samples are analyzed for H/sub 2/O/sub 2/ in the field. Storage periods exceeding 1 h caused serious errors and irreproducible results.

  5. Materials Compatibility in High Test Hydrogen Peroxide

    NASA Technical Reports Server (NTRS)

    Gostowski, Rudy

    1999-01-01

    Previous ratings of the compatibility of high test hydrogen peroxide (HTP) with materials are not adequate for current needs. The goal of this work was to develop a new scheme of evaluation of compatibility of HTP with various materials. Procedures were developed to enrich commercially available hydrogen peroxide to 90% concentration and to assay the product. Reactivity testing, accelerated aging of materials and calorimetry studies were done on HTP with representative metallic and non-metallic materials. It was found that accelerated aging followed by concentration determination using refractive index effectively discriminated between different Class 2 metallic materials. Preliminary experiments using Differential Scanning Calorimetry (DSC) suggest that a calorimetry experiment is the most sensitive means to assay the compatibility of HTP with materials.

  6. Hydrogen Peroxide: A Potential Wound Therapeutic Target.

    PubMed

    Zhu, Guanya; Wang, Qi; Lu, Shuliang; Niu, Yiwen

    2017-04-05

    Hydrogen peroxide (H2O2) is a topical antiseptic used in wound cleaning which kills pathogens through oxidation burst and local oxygen production. Hydrogen peroxide had been reported to be a reactive biochemical molecule synthesized by various cells which influences biological behavior through multiple mechanisms: alterations of membrane potential, generation of new molecules and changing intracellular redox balance which results in activation or inactivation of different signaling transduction pathways. Contrary to the traditional viewpoint that H2O2 probably impairs tissue through its high oxidative property, however, a proper level of H2O2 is considered as an important requirement for normal wound healing. Although the present clinical use of H2O2 is still limited to the elimination of microbial contamination and sometimes hemostasis, better understanding towards the sterilization ability and cell behavior regulatory function of H2O2 within wound will enhance the potential to exogenously augment and manipulate healing.

  7. Materials Compatibility in High Test Hydrogen Peroxide

    NASA Technical Reports Server (NTRS)

    Gostowski, Rudy

    1999-01-01

    Previous ratings of the compatibility of high test hydrogen peroxide (HTP) with materials are not adequate for current needs. The goal of this work was to develop a new scheme of evaluation of compatibility of HTP with various materials. Procedures were developed to enrich commercially available hydrogen peroxide to 90% concentration and to assay the product. Reactivity testing, accelerated aging of materials and calorimetry studies were done on HTP with representative metallic and non-metallic materials. It was found that accelerated aging followed by concentration determination using refractive index effectively discriminated between different Class 2 metallic materials. Preliminary experiments using Differential Scanning Calorimetry (DSC) suggest that a calorimetry experiment is the most sensitive means to assay the compatibility of HTP with materials.

  8. Time-course diffusion of hydrogen peroxide using modern technologies

    NASA Astrophysics Data System (ADS)

    Florez, F. L. E.; Vollet-Filho, J. D.; Oliveira-Junior, O. B.; Bagnato, V. S.

    2009-02-01

    The concern with the hydrogen penetration towards the pulp can be observed on the literature by the great number of papers published on this topic; Those measurements often uses chemical agents to quantify the concentration of the bleaching agent that cross the enamel and dentin. The objective of this work was the quantification of oxygen free radicals by fluorescence that are located in the interface between enamel and dentin. It was used to accomplish our objectives a Ruthenium probe (FOXY R - Ocean Optics) a 405nm LED, a bovine tooth and a portable diagnostic system (Science and support LAB - LAT - IFSC/USP). The fluorescence of the probe is suppressed in presence of oxygen free radicals in function of time. The obtained results clearly shows that the hydrogen peroxide when not catalyzed should be kept in contact with the tooth for longer periods of time.

  9. Palladium catalyzed hydrogenation of bio-oils and organic compounds

    DOEpatents

    Elliott, Douglas C [Kennewick, WA; Hu, Jianli [Richland, WA; Hart,; Todd, R [Kennewick, WA; Neuenschwander, Gary G [Burbank, WA

    2011-06-07

    The invention provides palladium-catalyzed hydrogenations of bio-oils and certain organic compounds. Experimental results have shown unexpected and superior results for palladium-catalyzed hydrogenations of organic compounds typically found in bio-oils.

  10. Palladium catalyzed hydrogenation of bio-oils and organic compounds

    DOEpatents

    Elliott, Douglas C.; Hu, Jianli; Hart, Todd R.; Neuenschwander, Gary G.

    2008-09-16

    The invention provides palladium-catalyzed hydrogenations of bio-oils and certain organic compounds. Experimental results have shown unexpected and superior results for palladium-catalyzed hydrogenations of organic compounds typically found in bio-oils.

  11. THE DECOMPOSITION OF HYDROGEN PEROXIDE BY LIVER CATALASE

    PubMed Central

    Williams, John

    1928-01-01

    1. The velocity of decomposition of hydrogen peroxide by catalase as a function of (a) concentration of catalase, (b) concentration of hydrogen peroxide, (c) hydrogen ion concentration, (d) temperature has been studied in an attempt to correlate these variables as far as possible. It is concluded that the reaction involves primarily adsorption of hydrogen peroxide at the catalase surface. 2. The decomposition of hydrogen peroxide by catalase is regarded as involving two reactions, namely, the catalytic decomposition of hydrogen peroxide, which is a maximum at the optimum pH 6.8 to 7.0, and the "induced inactivation" of catalase by the "nascent" oxygen produced by the hydrogen peroxide and still adhering to the catalase surface. This differs from the more generally accepted view, namely that the induced inactivation is due to the H2O2 itself. On the basis of the above view, a new interpretation is given to the equation of Yamasaki and the connection between the equations of Yamasaki and of Northrop is pointed out. It is shown that the velocity of induced inactivation is a minimum at the pH which is optimal for the decomposition of hydrogen peroxide. 3. The critical increment of the catalytic decomposition of hydrogen peroxide by catalase is of the order 3000 calories. The critical increment of induced inactivation is low in dilute hydrogen peroxide solutions but increases to a value of 30,000 calories in concentrated solutions of peroxide. PMID:19872400

  12. ESR ST study of hydroxyl radical generation in wet peroxide system catalyzed by heterogeneous ruthenium.

    PubMed

    Rokhina, Ekaterina V; Golovina, Elena A; As, Henk van; Virkutyte, Jurate

    2009-09-01

    Ru-based catalysts gained popularity because of their applicability for a variety of processes, including carbon monoxide oxidation, wet air catalytic oxidation and wastewater treatment. The focus of a current study was generation of hydroxyl radicals in the wet peroxide system catalyzed by heterogeneous ruthenium, spin-trapped by DEPMPO and DIPPMPO by means of electron spin resonance spin-trapping technique (ESR ST). The mechanism of free radicals formation was proposed via direct cleavage of hydrogen peroxide over ruthenium active sites. The chemical reactions occurring in the system were introduced according to the experimental results. Also, radical production rate was assessed based on concentration changes of species involved in the bulk liquid phase oxidation.

  13. PROCESS OF ELIMINATING HYDROGEN PEROXIDE IN SOLUTIONS CONTAINING PLUTONIUM VALUES

    DOEpatents

    Barrick, J.G.; Fries, B.A.

    1960-09-27

    A procedure is given for peroxide precipitation processes for separating and recovering plutonium values contained in an aqueous solution. When plutonium peroxide is precipitated from an aqueous solution, the supernatant contains appreciable quantities of plutonium and peroxide. It is desirable to process this solution further to recover plutonium contained therein, but the presence of the peroxide introduces difficulties; residual hydrogen peroxide contained in the supernatant solution is eliminated by adding a nitrite or a sulfite to this solution.

  14. Hazard Assessment of Personal Protective Clothing for Hydrogen Peroxide Service

    NASA Technical Reports Server (NTRS)

    Greene, Ben; McClure, Mark B.; Johnson, Harry T.

    2004-01-01

    Selection of personal protective equipment (PPE) for hydrogen peroxide service is an important part of the hazard assessment process. But because drip testing of chemical protective clothing for hydrogen peroxide service has not been reported for about 40 years, it is of great interest to test new protective clothing materials with new, high-concentration hydrogen peroxide following similar procedures. The suitability of PPE for hydrogen peroxide service is in part determined by observations made when hydrogen peroxide is dripped onto swatches of protective clothing material. Protective clothing material was tested as received, in soiled condition, and in grossly soiled condition. Materials were soiled by pretreating the material with potassium permanganate (KMnO4) solution then drying to promote a reaction. Materials were grossly soiled with solid KMnO4 to greatly promote reaction. Observations of results including visual changes to the hydrogen peroxide and materials, times to ignition, and self-extinguishing characteristics of the materials are reported.

  15. Oxygen from Hydrogen Peroxide: An Experimental Modification

    NASA Astrophysics Data System (ADS)

    Burness, James H.

    1996-09-01

    A common experiment, performed at the high school and college levels, is the generation of a gas to explore molar mass and molar volume relationships. In one version of this experiment, hydrogen peroxide is decomposed by yeast to generate oxygen gas. This paper describes a simple modification to this experiment which eliminates the need for a pencil coated with petroleum jelly and dry yeast. This elimination not only prevents falling pieces of yeast from prematurely starting the reaction, but at the same time makes the reaction faster and simplifies cleanup. The modification also reduces the likelihood of cuts from broken tubing.

  16. Mechanisms of hydrogen peroxide-induced contraction of rat aorta.

    PubMed

    Yang, Z W; Zheng, T; Zhang, A; Altura, B T; Altura, B M

    1998-03-05

    of intracellular Ca2+ ([Ca2+]i) within 20 s. Employment of 1.0 microM Fe2+ markedly enhanced the increment in [Ca2+]i in the smooth muscle cells. 10 microM proadifen treatment failed to alter the hydrogen peroxide-induced increment in [Ca2+]i of the smooth muscle cells. However, the presence of 5 microM indomethacin significantly attenuated the rise in [Ca2+]i in smooth muscle cells. The present results suggest that H2O2 can induce contractions of rat aorta segments, at pathophysiological concentrations, which are Ca2+-dependent. Hydroxyl radicals (.OH), cyclooxygenase products, protein kinase C and products of protein tyrosine phosphorylation appear to play some role in hydrogen peroxide-induced contractions. Metabolites catalyzed by cytochrome P450-dependent enzymes (upon treatment with hydrogen peroxide) appear to exert a vasodilator effect on rat aorta segments. Lastly, some unidentified mediators, produced by a cytochrome P450 inhibitor (proadifen), during hydrogen peroxide treatment, appear to play some role in contraction of vascular smooth muscle of rat aorta segments in vitro.

  17. Enhanced stability of hydrogen peroxide in the presence of subsurface solids

    NASA Astrophysics Data System (ADS)

    Watts, Richard J.; Finn, Dennis D.; Cutler, Lynn M.; Schmidt, Jeremy T.; Teel, Amy L.

    2007-05-01

    The stabilization of hydrogen peroxide was investigated as a basis for enhancing its downgradient transport and contact with contaminants during catalyzed H 2O 2 propagations (CHP) in situ chemical oxidation (ISCO). Stabilization of hydrogen peroxide was investigated in slurries containing four characterized subsurface solids using phytate, citrate, and malonate as stabilizing agents after screening ten potential stabilizers. The extent of hydrogen peroxide stabilization and the most effective stabilizer were solid-specific; however, phytate was usually the most effective stabilizer, increasing the hydrogen peroxide half-life to as much as 50 times. The degree of stabilization was nearly as effective at 10 mM concentrations as at 250 mM or 1 M concentrations. The effect of stabilization on relative rates of hydroxyl radical activity varied between the subsurface solids, but citrate and malonate generally had a greater positive effect than phytate. The effect of phytate, citrate, and malonate on the relative rates of superoxide generation was minimal to somewhat negative, depending on the solid. The results of this research demonstrate that the stabilizers phytate, citrate, and malonate can significantly increase the half-life of hydrogen peroxide in the presence of subsurface solids during CHP reactions while maintaining a significant portion of the reactive oxygen species activity. Use of these stabilizers in the field will likely improve the delivery of hydrogen peroxide and downgradient treatment during CHP ISCO.

  18. [Carbamide peroxide as source of hydrogen peroxide for the luminol application at crime scenes].

    PubMed

    Schwarz, Lothar; Hermanowski, Mona-Lena

    2009-01-01

    The solution of hydrogen peroxide is a critical ingredient of the Weber luminol application for blood detection at the crime scene. An ideal alternative to the unstable hydrogen peroxide is a solid compound which is easy to transport, stable and quick to solve in water at the crime scene. Carbamide peroxide (urea peroxide) is one of these solid hydrogen peroxide carriers which is easy to obtain as one gram tablets. At dry conditions it is stable over a long period at room temperature and even for a short time at higher temperatures. But at 70 degrees C (180 degrees F) the tablets go out of shape and cake after one hour. In the application of luminol there are no differences between the use of hydrogen peroxide and carbamide peroxide.

  19. Development of a highly sensitive fluorescence probe for hydrogen peroxide.

    PubMed

    Abo, Masahiro; Urano, Yasuteru; Hanaoka, Kenjiro; Terai, Takuya; Komatsu, Toru; Nagano, Tetsuo

    2011-07-13

    Hydrogen peroxide is believed to play a role in cellular signal transduction by reversible oxidation of proteins. Here, we report the design and synthesis of a novel fluorescence probe for hydrogen peroxide, utilizing a photoinduced electron transfer strategy based on benzil chemistry to control the fluorescence. The practical value of this highly sensitive and selective fluorescence probe, NBzF, was confirmed by its application to imaging of hydrogen peroxide generation in live RAW 264.7 macrophages. NBzF was also employed for live cell imaging of hydrogen peroxide generated as a signaling molecule in A431 human epidermoid carcinoma cells.

  20. Method for detection of hydrogen peroxide in HT22 cells

    PubMed Central

    Jacewicz, Dagmara; Siedlecka-Kroplewska, Kamila; Drzeżdżon, Joanna; Piotrowska, Agnieszka; Wyrzykowski, Dariusz; Tesmar, Aleksandra; Żamojć, Krzysztof; Chmurzyński, Lech

    2017-01-01

    We have proposed a new method which can be applied in assessing the intracellular production of hydrogen peroxide. Using this assay we have examined the hydrogen peroxide generation during the L-glutamate induced oxidative stress in the HT22 hippocampal cells. The detection of hydrogen peroxide is based on two crucial reagents cis-[Cr(C2O4)(pm)(OH2)2]+ (pm denotes pyridoxamine) and 2-ketobutyrate. The results obtained indicate that the presented method can be a promising tool to detect hydrogen peroxide in biological samples, particularly in cellular experimental models. PMID:28358356

  1. Use of Hydrogen Peroxide to Disinfect Hydroponic Plant Growth Systems

    NASA Technical Reports Server (NTRS)

    Barta, Daniel J.; Henderson, Keith

    2000-01-01

    Hydrogen peroxide was studied as an alternative to conventional bleach and rinsing methods to disinfect hydroponic plant growth systems. A concentration of 0.5% hydrogen peroxide was found to be effective. Residual hydrogen peroxide can be removed from the system by repeated rinsing or by flowing the solution through a platinum on aluminum catalyst. Microbial populations were reduced to near zero immediately after treatment but returned to pre-disinfection levels 2 days after treatment. Treating nutrient solution with hydrogen peroxide and planting directly into trays being watered with the nutrient solution without replenishment, was found to be detrimental to lettuce germination and growth.

  2. Monolithic Hydrogen Peroxide Catalyst Bed Development

    NASA Technical Reports Server (NTRS)

    Ponzo, J. B.

    2003-01-01

    With recent increased industry and government interest in rocket grade hydrogen peroxide as a viable propellant, significant effort has been expended to improve on earlier developments. This effort has been predominately centered in improving heterogeneous. typically catalyst beds; and homogeneous catalysts, which are typically solutions of catalytic substances. Heterogeneous catalyst beds have traditionally consisted of compressed wire screens plated with a catalytic substance, usually silver, and were used m many RCS applications (X-1, Mercury, and Centaur for example). Aerojet has devised a heterogeneous catalyst design that is monolithic (single piece), extremely compact, and has pressure drops equal to or less than traditional screen beds. The design consists of a bonded stack of very thin, photoetched metal plates, silver coated. This design leads to a high surface area per unit volume and precise flow area, resulting in high, stable, and repeatable performance. Very high throughputs have been demonstrated with 90% hydrogen peroxide. (0.60 lbm/s/sq in at 1775-175 psia) with no flooding of the catalyst bed. Bed life of over 900 seconds has also been demonstrated at throughputs of 0.60 lbm/s/sq in across varying chamber pressures. The monolithic design also exhibits good starting performance, short break-in periods, and will easily scale to various sizes.

  3. PROPULSE 980: A Hydrogen Peroxide Enrichment System

    NASA Technical Reports Server (NTRS)

    Boxwell, Robert; Bromley, G.; Wanger, Robert; Pauls, Dan; Maynard, Bryon; McNeal, Curtis; Dumbacher, D. L. (Technical Monitor)

    2000-01-01

    The PROPULSE 980 unit is a transportable processing plant that enriches aerospace grade hydrogen peroxide from 90% to 98% final concentration. The unit was developed by Degussa-H Is, in cooperation with Orbital, NASA Marshall Space Center, and NASA Stennis Space Center. The system is a self-contained unit that houses all of the process equipment, instrumentation and controls to perform the concentration operation nearly autonomously. It is designed to produce non-bulk quantities of 98% hydrogen peroxide. The enrichment unit design also maintains system, personnel and environmental safety during all aspects of the enrichment process and final product storage. As part of the Propulse 980 checkout and final buyoff, it will be disassembled at the Degussa-H Is Corporation plant in Theodore, AL, transported to the Stennis Space Center, reassembled and subjected to a series of checkout tests to verify design objectives have been met. This paper will summarize the basic project elements and provide an update on the present status of the project.

  4. Simple, field portable colorimetric detection device for organic peroxides and hydrogen peroxide

    DOEpatents

    Pagoria, Philip F.; Mitchell, Alexander R.; Whipple, Richard E.; Carman, M. Leslie; Reynolds, John G.; Nunes, Peter; Shields, Sharon J.

    2010-11-09

    A simple and effective system for the colorimetric determination of organic peroxides and hydrogen peroxide. A peroxide pen utilizing a swipe material attached to a polyethylene tube contains two crushable vials. The two crushable vials contain a colorimetric reagent separated into dry ingredients and liquid ingredients. After swiping a suspected substance or surface the vials are broken, the reagent is mixed thoroughly and the reagent is allowed to wick into the swipe material. The presence of organic peroxides or hydrogen peroxide is confirmed by a deep blue color.

  5. Switching off hydrogen peroxide hydrogenation in the direct synthesis process.

    PubMed

    Edwards, Jennifer K; Solsona, Benjamin; N, Edwin Ntainjua; Carley, Albert F; Herzing, Andrew A; Kiely, Christopher J; Hutchings, Graham J

    2009-02-20

    Hydrogen peroxide (H2O2) is an important disinfectant and bleach and is currently manufactured from an indirect process involving sequential hydrogenation/oxidation of anthaquinones. However, a direct process in which H2 and O2 are reacted would be preferable. Unfortunately, catalysts for the direct synthesis of H2O2 are also effective for its subsequent decomposition, and this has limited their development. We show that acid pretreatment of a carbon support for gold-palladium alloy catalysts switches off the decomposition of H2O2. This treatment decreases the size of the alloy nanoparticles, and these smaller nanoparticles presumably decorate and inhibit the sites for the decomposition reaction. Hence, when used in the direct synthesis of H2O2, the acid-pretreated catalysts give high yields of H2O2 with hydrogen selectivities greater than 95%.

  6. Solid state and solution 43Ca NMR of calcium peroxides involved in the disproportionation of hydrogen peroxide by calcium hydroxide.

    PubMed

    Trokiner, Arlette; Bessière, Aurélie; Thouvenot, René; Hau, Damien; Marko, Jean; Nardello, Véronique; Pierlot, Christel; Aubry, Jean-Marie

    2004-06-01

    In order to get some insight into the mechanism of the disproportionation of hydrogen peroxide catalyzed by calcium hydroxide, 43Ca NMR spectra of enriched samples of calcium peroxides and of their precursors have been studied in both solution and solid state. This study demonstrates that no well-defined peroxidized calcium species are formed in solution, showing that the catalytic role of calcium is likely restricted to the solid state. Most of the calcium compounds that could be involved in the catalytic process have been investigated with solid state NMR. The shift and quadrupolar parameters of Ca(OH)2, CaO2.8H2O and CaO2.2H2O2 are reported for the first time. These parameters are different enough to allow the quantitative analysis of a complex mixture of these compounds by NMR.

  7. Selective detection of vapor phase hydrogen peroxide with phthalocyanine chemiresistors.

    PubMed

    Bohrer, Forest I; Colesniuc, Corneliu N; Park, Jeongwon; Schuller, Ivan K; Kummel, Andrew C; Trogler, William C

    2008-03-26

    The use of hydrogen peroxide as a precursor to improvised explosives has made its detection a topic of critical importance. Chemiresistor arrays comprised of 50 nm thick films of metallophthalocyanines (MPcs) are redox selective vapor sensors of hydrogen peroxide. Hydrogen peroxide is shown to decrease currents in cobalt phthalocyanine sensors while it increases currents in nickel, copper, and metal-free phthalocyanine sensors; oxidation and reduction of hydrogen peroxide via catalysis at the phthalocyanine surface are consistent with the pattern of sensor responses. This represents the first example of MPc vapor sensors being oxidized and reduced by the same analyte by varying the metal center. Consequently, differential analysis by redox contrast with catalytic amplification using a small array of sensors may be used to uniquely identify peroxide vapors. Metallophthalocyanine chemiresistors represent an improvement over existing peroxide vapor detection technologies in durability and selectivity in a greatly decreased package size.

  8. A Volumetric Method for Titrimetric Analysis of Hydrogen Peroxide

    DTIC Science & Technology

    1985-05-06

    side it necessary and iden~tify by block nambet) *Hydrogen Peroxide Quantitative Analysis *Potassium Dichromate * Volumetrie Analysis,~ Ferrous Ammonium ...report describes a titrimetric method (using ferrous- dichromate oxidation reduction) of analysis for hydrogen peroxide. The concept is theoretically...2 COMPARISON OF FERROUS SOLUTION TO DICHROMATE SOLUTION . . . . . . . . .. 3 PROCEDURE . . . . . . . . . . . . . . . . . 3 CALCULATIONS

  9. Hydrogen peroxide in the human body.

    PubMed

    Halliwell, B; Clement, M V; Long, L H

    2000-12-01

    Hydrogen peroxide (H(2)O(2)) is widely regarded as a cytotoxic agent whose levels must be minimized by the action of antioxidant defence enzymes. In fact, H(2)O(2) is poorly reactive in the absence of transition metal ions. Exposure of certain human tissues to H(2)O(2) may be greater than is commonly supposed: substantial amounts of H(2)O(2) can be present in beverages commonly drunk (especially instant coffee), in freshly voided human urine, and in exhaled air. Levels of H(2)O(2) in the human body may be controlled not only by catabolism but also by excretion, and H(2)O(2) could play a role in the regulation of renal function and as an antibacterial agent in the urine. Urinary H(2)O(2) levels are influenced by diet, but under certain conditions might be a valuable biomarker of 'oxidative stress'.

  10. Hydrogen peroxide measurements in the marine atmosphere

    NASA Astrophysics Data System (ADS)

    Jacob, P.; Klockow, D.

    1992-11-01

    Hydrogen peroxide, one of the key compounds in multiphase atmospheric chemistry, was measured on an Atlantic cruise (ANT VII/1) of the German research vessel Polarstern from 15 September to 9 October 1988, in rain and ambient air by a chemiluminescence technique. For gas-phase H2O2 cryogenic sampling was employed. The presented results show an increase of gas-phase mixing ratios of about 45 pptv per degree latitude between 50 deg N and 0 deg, and a maximum of 3.5 ppbv around the equator. Generally higher mixing ratios were observed in the Southern Hemisphere, with a clear diurnal variation. The H2O2 mixing ratio is correlated to the UV radiation intensity and to the temperature difference between air and ocean surface water.

  11. Measurement of hydrogen peroxide from aircraft

    SciTech Connect

    Kok, G.L.

    1980-01-01

    Hydrogen peroxide (H/sub 2/O/sub 2/) is an important species in both the homogeneous and the heterogeneous chemistry of the troposphere. Measurement of H/sub 2/O/sub 2/ from aircraft provides information on the distribution of H/sub 2/O/sub 2/ in the troposphere and provides a great deal of additional information which cannot be obtained from ground-based measurements. Three analytical techniques for atmospheric H/sub 2/O/sub 2/ are available. Two of these are colorimetric methods involving the formation of a colored complex with titanium salt. In 1978, a chemiluminescent method for the determination of atmospheric H/sub 2/O/sub 2/ was introduced. This method involves the reaction of H/sub 2/O/sub 2/ with luminol in the presence of a copper catalyst, with the chemiluminescence serving as the basis of the analytical reaction.

  12. Hydrogen Peroxide (HP) Potential for Space Applications

    NASA Astrophysics Data System (ADS)

    Grafwallner, F.

    2004-10-01

    Low toxicity or "green" propellants are now under study by organizations around the world. Especially ultra high concentrated hydrogen peroxide (HP) may be a significant step toward less toxic, storable und safer operation of upper stages and spacecrafts. HP can be used as a monopropellant, when catalytically decomposed or as a bipropellant constituting the propellant combination`s oxidizer. Serving as a monopropellant, catalytic decomposition will result in exhaust of superheated steam and oxygen which can be used to drive gas turbines and feed life support systems or provide thrust as a monopropellant, provide the oxidizer, or function as an igniter for bipropellant engines. HP can be used in fuel cells to produce electrical power, heat and water.

  13. Hydrogen Peroxide Storage in Small Sealed Tanks

    SciTech Connect

    Whitehead, J.

    1999-10-20

    Unstabilized hydrogen peroxide of 85% concentration has been prepared in laboratory quantities for testing material compatibility and long term storage on a small scale. Vessels made of candidate tank and liner materials ranged in volume from 1 cc to 2540 cc. Numerous metals and plastics were tried at the smallest scales, while promising ones were used to fabricate larger vessels and liners. An aluminum alloy (6061-T6) performed poorly, including increasing homogeneous decay due to alloying elements entering solution. The decay rate in this high strength aluminum was greatly reduced by anodizing. Better results were obtained with polymers, particularly polyvinylidene fluoride. Data reported herein include ullage pressures as a function of time with changing decay rates, and contamination analysis results.

  14. [Continuous Generation of Hydrogen Peroxide in Water Containing Very Low Concentrations of Unsymmetrical Dimethylhydrazine].

    PubMed

    Bruskov, V I; Yaguzhinsky, L S; Masalimov, Z K; Chernikov, A V; Emelyanenko, V I; Gudkov, S V

    2015-01-01

    Continuous generation of hydrogen peroxide catalyzed by low concentrations of 1,1-dimethylhydrazine (heptyl)--a rocket fuel component--in air saturated water was shown by the method of enhanced chemiluminescence in the system of luminol-p-iodophenol-peroxidase. The concentration dependence and the influence of heat and light on the formation of hydrogen peroxide in the water under the influence of dimethylhydrazine at concentrations considerably lower than maximum allowable concentrations were studied, and the physical-chemical mechanism of this process was considered. It is supposed that dimethylhydrazine at ultra-low concentrations is associated with air nanobubbles and represents a long-lived complex performing catalysis of hydrogen peroxide formation under the influence of heat and light. We put forward the new concept of.toxicity of dimethylhydrazine at very low concentrations due to violation of homeostasis of reactive oxygen species formation in aqueous solutions entering the body of humans and animals.

  15. Bactericidal effect of hydrogen peroxide on spacecraft isolates

    NASA Technical Reports Server (NTRS)

    Wardle, M. D.; Renninger, G. M.

    1975-01-01

    Results are presented for an experimental study designed to assess the effect of hydrogen peroxide on both sporeforming and nonsporeforming spacecraft isolates as an initial step in determining its suitability for microbiological decontamination of certain United States spacecraft. Survivor data were obtained for eight bacterial isolates (six sporeformers and two nonsporeformers) recovered before launch Mariner 9 and exposed to concentrations of 3, 10, and 15% hydrogen peroxide. The effects of various concentrations of hydrogen peroxide on the spores are presented in tabular form, along with the percentage of survival of nonsporeformers exposed to hydrogen peroxide. No viable vegetative cells were recovered after a 10-min exposure time to any of the three concentration of hydrogen peroxide.

  16. Uptake of methacrolein into aqueous solutions of sulfuric acid and hydrogen peroxide.

    PubMed

    Liu, Ze; Wu, Ling-Yan; Wang, Tian-He; Ge, Mao-Fa; Wang, Wei-Gang

    2012-01-12

    Multiphase acid-catalyzed oxidation by hydrogen peroxide has been suggested to be a potential route to secondary organic aerosol (SOA) formation from isoprene and its gas-phase oxidation products, but the kinetics and chemical mechanism remain largely uncertain. Here we report the first measurement of uptake of methacrolein into aqueous solutions of sulfuric acid and hydrogen peroxide in the temperature range of 253-293 K. The steady-state uptake coefficients were acquired and increased quickly with increasing sulfuric acid concentration and decreasing temperature. Propyne, acetone, and 2,3-dihydroxymethacrylic acid were suggested as the products. The chemical mechanism is proposed to be the oxidation of carbonyl group and C═C double bonds by peroxide hydrogen in acidic environment, which could explain the large content of polyhydroxyl compounds in atmospheric fine particles. These results indicate that multiphase acid-catalyzed oxidation of methacrolein by hydrogen peroxide can contribute to SOA mass in the atmosphere, especially in the upper troposphere.

  17. Intrinsic catalytic activity of Au nanoparticles with respect to hydrogen peroxide decomposition and superoxide scavenging.

    PubMed

    He, Weiwei; Zhou, Yu-Ting; Wamer, Wayne G; Hu, Xiaona; Wu, Xiaochun; Zheng, Zhi; Boudreau, Mary D; Yin, Jun-Jie

    2013-01-01

    Gold nanoparticles have received a great deal of interest due to their unique optical and catalytic properties and biomedical applications. Developing applications as well as assessing associated risks requires an understanding of the interactions between Au nanoparticles (NPs) and biologically active substances. In this paper, electron spin resonance spectroscopy (ESR) was used to investigate the catalytic activity of Au NPs in biologically relevant reactions. We report here that Au NPs can catalyze the rapid decomposition of hydrogen peroxide. Decomposition of hydrogen peroxide is accompanied by the formation of hydroxyl radicals at lower pH and oxygen at higher pH. In addition, we found that, mimicking SOD, Au NPs efficiently catalyze the decomposition of superoxide. These results demonstrate that Au NPs can act as SOD and catalase mimetics. Since reactive oxygen species are biologically relevant products being continuously generated in cells, these results obtained under conditions resembling different biological microenvironments may provide insights for evaluating risks associated with Au NPs.

  18. Marine Photochemistry of Hydrogen Peroxide in the Northwest Pacific Ocean

    NASA Astrophysics Data System (ADS)

    Yuan, J.; Shiller, A. M.

    2002-12-01

    A systematical study of hydrogen peroxide in seawater, rainwater, and marine air in the Northwest Pacific Ocean was conducted during a transect from Osaka, Japan, to Hawaii, USA, in May and June of 2002. During the transect, surface seawater samples were analyzed continuously for peroxide which showed the effects of photochemical production, wet deposition, and terrestrial impact. In the surface waters, hydrogen peroxide decreased with latitude from a little over 25 nM in the north (50°N) to more than 150 nM in the south (22°N). This latitudinal variation of hydrogen peroxide followed a trend similar to shipboard measurement of ultraviolet radiation. Diel variations of surface hydrogen peroxide were observed at several locations, with surface water concentrations increasing during the day and decreasing at night. The concentration of surface water peroxide increased to over 200 nM following rain events. Higher concentrations of hydrogen peroxide (>150 nM) were also observed near Asia. The profiles of hydrogen peroxide were obtained at 10 stations that exhibited surface maxima of 24 to 120 nM. The rate constant of dark decay varied from 0.08 d-1 to 0.22 d-1. Rate of photo-production decreased from 10 nM hr-1 at noon to 0 at night. The concentration of hydrogen peroxide varied from 16 μM to 526 μM in rainwater. The data set permits a systematical analysis and modeling of factors regulating the dynamics of hydrogen peroxide in marine environment.

  19. Hydrogen peroxide mechanosynthesis in siloxane-hydrogel contact lenses.

    PubMed

    Tavazzi, Silvia; Ferraro, Lorenzo; Cozza, Federica; Pastori, Valentina; Lecchi, Marzia; Farris, Stefano; Borghesi, Alessandro

    2014-11-26

    Drug-loaded contact lenses are emerging as the preferred treatment method for several ocular diseases, and efforts are being directed to promote extended and controlled delivery. One strategy is based on delivery induced by environmental triggers. One of these triggers can be hydrogen peroxide, since many platforms based on drug-loaded nanoparticles were demonstrated to be hydrogen-peroxide responsive. This is particularly interesting when hydrogen peroxide is the result of a specific pathophysiological condition. Otherwise, an alternative route to induce drug delivery is here proposed, namely the mechano-synthesis. The present work represents the proof-of-concept of the mechanosynthesis of hydrogen peroxide in siloxane-hydrogel contact lenses as a consequence of the cleavage of siloxane bonds at the interface between the polymer and water in aqueous phase. Their spongy morphology makes contact lenses promising systems for mechanical-to-chemical energy conversion, since the amount of hydrogen peroxide is expected to scale with the interfacial area between the polymer and water. The eyelid pressure during wear is sufficient to induce the hydrogen peroxide synthesis with concentrations which are biocompatible and suitable to trigger the drug release through hydrogen-peroxide-responsive platforms. For possible delivery on demand, the integration of piezoelectric polymers in the siloxane-hydrogel contact lenses could be designed, whose mechanical deformation could be induced by an applied wireless-controlled voltage.

  20. Hydrogen peroxide production, chemiluminescence, and the respiratory burst of fertilization: Interrelated events in early sea urchin development

    PubMed Central

    Foerder, Charles A.; Klebanoff, Seymour J.; Shapiro, Bennett M.

    1978-01-01

    After fertilization of the sea urchin, Strongyl-ocentrotus purpuratus, a crosslinked fertilization membrane is formed; the crosslinks (dityrosine residues) are synthesized in a reaction catalyzed by an ovoperoxidase that is released from the cortical granules during fertilization. The substrate for ovoperoxidase activity, hydrogen peroxide, is generated by the egg coincident with the “respiratory burst” that follows parthenogenetic activation by the divalent ionophore A23187 or fertilization. This burst of oxygen consumption may be almost quantitatively accounted for by hydrogen peroxide evolution, as measured by the peroxidase-catalyzed quenching of scopoletin fluorescence. Neither the burst of oxygen consumption nor hydrogen peroxide production occurs when the inhibitor of cortical granule discharge, procaine, is present at fertilization. Fertilization or parthenogenetic activation with A23187 also is associated with a burst of light emission. This chemiluminescence is inhibited in vivo by inhibitors of the ovoperoxidase, such as 3-amino-1,2,4-triazole, phenylhydrazine, sulfite, or azide. A crude ovoperoxidase preparation catalyzes hydrogen peroxide-dependent chemiluminescence that is similarly inhibited. Thus, the bursts of oxygen uptake, peroxide production, and chemiluminescence appear to be several manifestations of the peroxidative system released at fertilization. This system may additionally be responsible for spermicidal activity and thus may act as a component of the block to polyspermy. PMID:277920

  1. Materials Compatibility Testing in Concentrated Hydrogen Peroxide

    NASA Technical Reports Server (NTRS)

    Boxwell, R.; Bromley, G.; Mason, D.; Crockett, D.; Martinez, L.; McNeal, C.; Lyles, G. (Technical Monitor)

    2000-01-01

    Materials test methods from the 1960's have been used as a starting point in evaluating materials for today's space launch vehicles. These established test methods have been modified to incorporate today's analytical laboratory equipment. The Orbital test objective was to test a wide range of materials to incorporate the revolution in polymer and composite materials that has occurred since the 1960's. Testing is accomplished in 3 stages from rough screening to detailed analytical tests. Several interesting test observations have been made during this testing and are included in the paper. A summary of the set-up, test and evaluation of long-term storage sub-scale tanks is also included. This sub-scale tank test lasted for a 7-month duration prior to being stopped due to a polar boss material breakdown. Chemical evaluations of the hydrogen peroxide and residue left on the polar boss surface identify the material breakdown quite clearly. The paper concludes with recommendations for future testing and a specific effort underway within the industry to standardize the test methods used in evaluating materials.

  2. Hydrogen peroxide mediated transvaginal drug delivery.

    PubMed

    Fatakdawala, Hussain; Uhland, Scott A

    2011-05-16

    Simple, safe and effective permeability enhancers are crucial for successful non-invasive drug delivery methods. We seek local permeability augmentation mechanisms for integration into passive or active architectures in order to enable novel therapeutic delivery routes of the target drug while minimizing drug formulation challenges. This study explores the efficacy of hydrogen peroxide (HP) as a permeability enhancer for transmucosal delivery of macromolecules. HP at low concentrations (2–8 mM) is an effective permeability enhancer that is locally metabolized and safe. HP improves drug permeation through mucosa by altering tight junctions (TJ) between cells and oxidizing enzymes that function to degrade the foreign species. Results from trans-epithelial electrical resistance measurements and cell viability assay show reversible disassembly of TJ with minimal cell damage demonstrating the feasibility of HP as a safe permeability enhancer for drug delivery. Permeation studies show that HP treatment of cell cultured vaginal mucosa significantly enhances the permeability to insulin by more than an order of magnitude. This work lays foundation for the development of a drug delivery platform that administers drug doses by enhancing the permeability of local epithelial tissue via a separate HP treatment step.

  3. Hydrogen peroxide diffusion dynamics in dental tissues.

    PubMed

    Ubaldini, A L M; Baesso, M L; Medina Neto, A; Sato, F; Bento, A C; Pascotto, R C

    2013-07-01

    The aim of this study was to investigate the diffusion dynamics of 25% hydrogen peroxide (H2O2) through enamel-dentin layers and to correlate it with dentin's structural alterations. Micro-Raman Spectroscopy (MRS) and Fourier Transform Infrared Photoacoustic Spectroscopy (FTIR-PAS) were used to measure the spectra of specimens before and during the bleaching procedure. H2O2 was applied to the outer surface of human enamel specimens for 60 minutes. MRS measurements were performed on the inner surface of enamel or on the subsurface dentin. In addition, H2O2 diffusion dynamics from outer enamel to dentin, passing through the dentin-enamel junction (DEJ) was obtained with Raman transverse scans. FTIR-PAS spectra were collected on the outer dentin. MRS findings revealed that H2O2 (O-O stretching µ-Raman band) crossed enamel, had a more marked concentration at DEJ, and accumulated in dentin. FTIR-PAS analysis showed that H2O2 modified dentin's organic compounds, observed by the decrease in amides I, II, and III absorption band intensities. In conclusion, H2O2 penetration was demonstrated to be not merely a physical passage through enamel interprismatic spaces into the dentinal tubules. H2O2 diffusion dynamics presented a concentration gradient determined by the chemical affinity of the H2O2 with each specific dental tissue.

  4. Locating bomb factories by detecting hydrogen peroxide.

    PubMed

    Romolo, Francesco Saverio; Connell, Samantha; Ferrari, Carlotta; Suarez, Guillaume; Sauvain, Jean-Jacques; Hopf, Nancy B

    2016-11-01

    The analytical capability to detect hydrogen peroxide vapour can play a key role in localizing a site where a H2O2 based Improvised Explosive (IE) is manufactured. In security activities it is very important to obtain information in a short time. For this reason, an analytical method to be used in security activity needs portable devices. The authors have developed the first analytical method based on a portable luminometer, specifically designed and validated to locate IE manufacturing sites using quantitative on-site vapour analysis for H2O2. The method was tested both indoor and outdoor. The results demonstrate that the detection of H2O2 vapours could allow police forces to locate the site, while terrorists are preparing an attack. The collected data are also very important in developing new sensors, able to give an early alarm if located at a proper distance from a site where an H2O2 based IE is prepared. Copyright © 2016 Elsevier B.V. All rights reserved.

  5. The electrochemistry of SIMFUEL in dilute alkaline hydrogen peroxide solutions

    NASA Astrophysics Data System (ADS)

    Goldik, Jon

    The work described in this thesis is a study of the electrochemistry of SIMFUEL (SIMulated nuclear FUEL) in dilute, alkaline hydrogen peroxide solutions. In the first set of experiments, the reaction of H2O 2 on SIMFUEL electrodes was studied electrochemically and under open circuit conditions in 0.1 mol L-1 NaCl solutions at pH 9.8. The composition of the oxidized UO2 surface was determined by X-ray photoelectron spectroscopy. Hydrogen peroxide reduction was found to be catalyzed by the formation of a mixed UIV/UV (UO 2+x) surface layer, but to be blocked by the accumulation of UVI species (UO3· yH2O or adsorbed (UO2)2+) on the electrode surface. The formation of this UVI layer blocks both H2O2 reduction and oxidation, thereby inhibiting the potentially rapid H2O2 decomposition reaction to H2O and O2. Decomposition is found to proceed at a rate controlled by the desorption of the adsorbed (UO2)2+ or reduction of adsorbed O2 species. Reduction of (O2) ads is coupled to the slow oxidative dissolution of UO2 and formation of a corrosion product deposit of UO3· yH2O. In the second series of experiments, the electrochemical reduction of hydrogen peroxide on SIMFUEL was studied using the steady-state polarization technique. Kinetic parameters for the reaction, such as Tafel slopes and reaction orders, were determined. The results were interpreted in terms of a chemical-electrochemical mechanism involving UIV/UV donor-acceptor reduction sites. The large values of the Tafel slopes and the fractional reaction orders with respect to H2O2 can be understood in terms of the potential-dependent surface coverage of active sites, similar to that observed in the reduction of hydrogen peroxide on oxidized copper surfaces. The effects of pH over the range 10-13 were also investigated. The H2O 2 reduction currents were nearly independent of pH in the range 10-11, but were slowed at more alkaline values. The change in pH dependence appears to be related to the acid-base properties

  6. Titrimetric determination of hydrogen peroxide in alkaline solution.

    PubMed

    McCurdy, W H; Bell, H F

    1966-07-01

    Direct titration of hydrogen peroxide in alkaline bromide media has been accomplished with sodium hypochlorite. The relative standard deviation is 0.2%. A photometric end-point is recommended for the determination of 0.10-1.0 mequiv of peroxide. Larger samples are evaluated by use of Bordeaux Red as visual indicator. The hypochlorite procedure compares favourably with iodometry and permanganate in the analysis of commercial peroxides.

  7. THE PRODUCTION OF HYDROGEN PEROXIDE BY HIGH OXYGEN PRESSURES

    PubMed Central

    Gilbert, Daniel L.; Gerschman, Rebeca; Ruhm, K. Barclay; Price, William E.

    1958-01-01

    Hydrogen peroxide is formed in solutions of glutathione exposed to oxygen. This hydrogen peroxide or its precursors will decrease the viscosity of polymers like desoxyribonucleic acid and sodium alginate. Further knowledge of the mechanism of these chemical effects of oxygen might further the understanding of the biological effects of oxygen. This study deals with the rate of solution of oxygen and with the decomposition of hydrogen peroxide in chemical systems exposed to high oxygen pressures. At 6 atmospheres, the absorption coefficient for oxygen into water was about 1 cm./hour and at 143 atmospheres, it was about 2 cm./hour; the difference probably being due to the modus operandi. The addition of cobalt (II), manganese (II), nickel (II), or zinc ions in glutathione (GSH) solutions exposed to high oxygen pressure decreased the net formation of hydrogen peroxide and also the reduced glutathione remaining in the solution. Studies on hydrogen peroxide decomposition indicated that these ions act probably by accelerating the hydrogen perioxide oxidation of glutathione. The chelating agent, ethylenediaminetetraacetic acid disodium salt, inhibited the oxidation of GSH exposed to high oxygen pressure for 14 hours. However, indication that oxidation still occurred, though at a much slower rate, was found in experiments lasting 10 weeks. Thiourea decomposed hydrogen peroxide very rapidly. When GSH solutions were exposed to high oxygen pressure, there was oxidation of the GSH, which became relatively smaller with increasing concentrations of GSH. PMID:13525677

  8. Determination of hydrogen peroxide concentrations by flow injection analysis based on the enhanced chemiluminescent reaction using peroxidase

    SciTech Connect

    Eremin, S.A.; Vlasenko, S.B.; Osipov, A.P.; Eremina, I.D.; Egerov, A.M. )

    1989-01-01

    The technique of flow injection analysis was employed in the determination of hydrogen peroxide. The method was based on the chemiluminescence reaction of luminol with H{sub 2}O{sub 2} which is catalyzed by horseradish peroxidase and enhanced by p-iodophenol. Hydrogen peroxide was linearly detected in the range 10{sup {minus}6}M-10{sup {minus}4}M by measuring the maximum intensity of light emitted. The detection limit is about 1 10{sup {minus}6}M hydrogen peroxide. Transition metal cations at millimolar concentrations do not have any interference on the determination of hydrogen peroxide by FIA based on the enhanced chemiluminescent reaction. This technique is relatively rapid and simple, and permits measurement of up to 80 samples/hr using generally available equipment.

  9. [Teeth whitening with 6% hydrogen peroxide vs. 35% hydrogen peroxide, a comparative controlled study].

    PubMed

    Zuabi, O

    2015-01-01

    In light of the lately changes in regulations regarding teeth whitening in Europe, the use of 6% hydrogen peroxide using a dedicated device becomes the first choice treatment option. The purpose of this controlled, randomized, parallel, blinded six months prospective study was to compare this method of teeth whitening treatment with that of in-office method using 35% hydrogen peroxide. 75 healthy american individuals, ages 18-62, participated in this study. The participants were divided into 3 groups: a 6% hydrogenperoxide group, a 35% hydrogen peroxide group and a placebo control group. Whitening procedures were performed on intact frontal teeth with color shade of A3 or higher. A controlled color measurement was performed before, immediately after, three and six months post treatment. Clinical periodontal indices, oral mucosa changes, side effects and participant satisfaction, were recorded. In the 6% group, the change in color shades immediately after treatment, three and six months after treatment were 2.37, 2.17 and 1.95, respectively. Tooth color changes in 35% group immediately after completion of treatment, three and six months after treatment were 3.68, 2.60 and 1.70, respectively. Statistical significant differences were found in both treatment groups between the baseline color shade and the post treatment color shade. The results were stable three and six months after treatment. Statistically significant difference between the groups immediately after treatment (p < 0.0001). No statistically significant difference was found between the two groups three and six months after treatment (p > 0.5000). Side effects such as oral mucosa irritation, burns or sensitive teeth were mild and resolved without intervention. A high satisfaction level was recorded. Tooth color shade can be substantially improved using a dedicated device with 6% hydrogen peroxide only. This whitening method can be helpful for the dentist in: home continuing treatment post in- office

  10. Electrochemical Visualization of Intracellular Hydrogen Peroxide at Single Cells.

    PubMed

    He, Ruiqin; Tang, Huifen; Jiang, Dechen; Chen, Hong-yuan

    2016-02-16

    In this Letter, the electrochemical visualization of hydrogen peroxide inside one cell was achieved first using a comprehensive Au-luminol-microelectrode and electrochemiluminescence. The capillary with a tip opening of 1-2 μm was filled with the mixture of chitosan and luminol, which was coated with the thin layers of polyvinyl chloride/nitrophenyloctyl ether (PVC/NPOE) and gold as the microelectrode. Upon contact with the aqueous hydrogen peroxide, hydrogen peroxide and luminol in contact with the gold layer were oxidized under the positive potential resulting in luminescence for the imaging. Due to the small diameter of the electrode, the microelectrode tip was inserted into one cell and the bright luminescence observed at the tip confirmed the visualization of intracellular hydrogen peroxide. The further coupling of oxidase on the electrode surface could open the field in the electrochemical imaging of intracellular biomolecules at single cells, which benefited the single cell electrochemical detection.

  11. [Risks of hydrogen peroxide irrigation in military surgery].

    PubMed

    Saïssy, J M; Guignard, B; Pats, B; Lenoir, B; Rouvier, B

    1994-01-01

    Two cases of severe complications due to injection of hydrogen peroxide under pressure into areas of muscular attrition in war wounds are reported. In both cases the administration of hydrogen peroxide was associated with tachypnoea, with major arterial desaturation and a precordial "mill-wheel" murmur was heard. In one case, these symptoms were followed by hemiplegia caused by paradoxical arterial gas embolism, and in the other case by a pulmonary oedema confirmed by computerized tomography. Both patients recovered under hyperbaric oxygen therapy. The release of gaseous oxygen under the effect of tissue catalase and the membrane peroxydasic activity of hydrogen peroxide initiate such complications. The injection of hydrogen peroxide under pressure into a closed or partially closed cavity should therefore be strictly prohibited.

  12. The contribution of hydrogen peroxide to atmospheric liquid phase chemistry

    SciTech Connect

    Klockow, D.; Jacob, P.; Bambauer, A.

    1986-04-01

    The most frequently investigated and best understood atmospheric liquid phase process is the oxidation of dissolved sulfur dioxide. The relevant reactions are controlled either by restricted solubilities of the respective species or by high activation energies. The most favorable properties as an oxidant for SO/sub 2/ (aq) under atmospheric conditions are exhibited by hydrogen peroxide: It is highly soluble in water and reacts fast with dissolved sulfur dioxide even at low pH values. In this talk new methodology for determination of hydrogen peroxide in liquid and gas phase is presented. Furthermore results of measurement of hydrogen peroxide in condensed phases (rain, snow, polar ice) as well as in the gas phase are discussed. Finally laboratory and field studies related to formation of hydrogen peroxide in the liquid phase and its reaction with dissolved reduced species ((HSO/sub 3/, NO/sub 2/) under the influence of light are described.

  13. Sodium Borohydride/Hydrogen Peroxide Fuel Cells For Space Application

    NASA Technical Reports Server (NTRS)

    Valdez, T. I.; Deelo, M. E.; Narayanan, S. R.

    2006-01-01

    This viewgraph presentation examines Sodium Borohydride and Hydrogen Peroxide Fuel Cells as they are applied to space applications. The topics include: 1) Motivation; 2) The Sodium Borohydride Fuel Cell; 3) Sodium Borohydride Fuel Cell Test Stands; 4) Fuel Cell Comparisons; 5) MEA Performance; 6) Anode Polarization; and 7) Electrode Analysis. The benefits of hydrogen peroxide as an oxidant and benefits of sodium borohydride as a fuel are also addressed.

  14. Sodium Borohydride/Hydrogen Peroxide Fuel Cells For Space Application

    NASA Technical Reports Server (NTRS)

    Valdez, T. I.; Deelo, M. E.; Narayanan, S. R.

    2006-01-01

    This viewgraph presentation examines Sodium Borohydride and Hydrogen Peroxide Fuel Cells as they are applied to space applications. The topics include: 1) Motivation; 2) The Sodium Borohydride Fuel Cell; 3) Sodium Borohydride Fuel Cell Test Stands; 4) Fuel Cell Comparisons; 5) MEA Performance; 6) Anode Polarization; and 7) Electrode Analysis. The benefits of hydrogen peroxide as an oxidant and benefits of sodium borohydride as a fuel are also addressed.

  15. Prediction and assignment of the FIR spectrum of hydrogen peroxide

    NASA Technical Reports Server (NTRS)

    Helminger, P.; Messer, J. K.; De Lucia, F. C.; Bowman, W. C.

    1984-01-01

    Millimeter and submillimeter microwave studies are used to predict and assign the FIR rotational-torsional spectrum of hydrogen peroxide. Special attention is given to the strong Q-branch features that have recently been used by Traub and Chance to place an upper limit on the atmospheric abundance of hydrogen peroxide. In addition, 67 new transitions are reported in the 400-1000 GHz region.

  16. Application of vapor phase hydrogen peroxide sterilization to endoscope.

    PubMed

    Shintani, Hideharu

    2009-03-01

    An advantage of vapor phase hydrogen peroxide (VPHP) is that it can readily react to form reactive free radicals, which perform the sterilization and form water and hydrogen by catalyst. Absorptive hydrophilic materials such as cellulosics hinder penetration due to hydrogen bonding and necessitate the use of hydrophobic materials, i.e., polyethylene or polypropylene, as packaging materials. The 8h TWA (time-weight-average) is 1 ppm. Hydrogen peroxide sterilization is now being used for the sterilization of gloveboxes, freeze dryers, isolators and endoscopes and so on. This paper focuses on the application of VPHP to the sterilization of the endoscopes.

  17. Sodium acetate enhances hydrogen peroxide production in Weissella cibaria.

    PubMed

    Endo, A; Futagawa-Endo, Y; Kawasaki, S; Dicks, L M T; Niimura, Y; Okada, S

    2009-07-01

    To investigate hydrogen peroxide production by lactic acid bacteria (LAB) and to determine the key factors involved. Six strains of Weissella cibaria produced large amounts (2.2-3.2 mmol l(-1)) of hydrogen peroxide in GYP broth supplemented with sodium acetate, but very low accumulations in glucose yeast peptone broth without sodium acetate. Increased production of hydrogen peroxide was also recorded when strains of W. cibaria were cultured in the presence of potassium acetate, sodium isocitrate and sodium citrate. Oxidases and peroxidases were not detected, or were present at low levels in W. cibaria. However, strong nicotinamide adenine dinucleotide (NADH) oxidase activity was recorded, suggesting that the enzyme plays a key role in production of hydrogen peroxide by W. cibaria. Weissella cibaria produces large quantities of hydrogen peroxide in aerated cultures, in a process that is dependent on the presence of acetate in the culture medium. NADH oxidase is likely the key enzyme in this process. This is the first study showing that sodium acetate, normally present in culture media of LAB, is a key factor for hydrogen peroxide production by W. cibaria. The exact mechanisms involved are not known.

  18. Hydrogen peroxide deposition and decomposition in rain and dew waters

    NASA Astrophysics Data System (ADS)

    Ortiz, Vicky; Angélica Rubio, M.; Lissi, Eduardo A.

    Peroxides and hydrogen peroxide were determined by a fluorometric method in dew and rain collected in the atmosphere of Santiago of Chile city. The measured peroxides comprise hydrogen peroxide (the main component) and peroxides not decomposed by catalase. The collected natural peroxides readily decompose in the natural matrix, rendering difficult an estimation of the values present in real-time. In order to establish the kinetics of the process and the factors that condition their decomposition, the kinetics of the decay at several pHs and/or the presence of metal chelators were followed. The kinetics of hydrogen peroxide decomposition in the water matrix was evaluated employing the natural peroxides or hydrogen peroxide externally added. First-order kinetics was followed, with half decay times ranging from 80 to 2300 min. The addition of Fe(II) in the micromolar range increases the decomposition rate, while lowering the pH (<3) notably reduces the rate of the process. The contribution of metals to the decomposition of the peroxides in the natural waters was confirmed by the reduction in decomposition rate elicited by its treatment with Chelex-100. Dew and rain waters were collected in pre-acidified collectors, rendering values considerably higher than those measured in non-treated collectors. This indicates that acidification can be proposed as an easy procedure to stabilize the samples, reducing its decomposition during collection time and the time elapsed between collection and analysis. The weighted average concentration for total peroxides measured in pre-treated collectors was 5.4 μM in rains and 2.2 μM in dews.

  19. Comparative Study on Oxidative Treatments of NAPL Containing Chlorinated Ethanes and Ethenes using Hydrogen Peroxide and Persulfate in Soils

    EPA Science Inventory

    The goal of this study was to assess the oxidation of NAPL in soil, 30% of which were composed of chlorinated ethanes and ethenes, using catalyzed hydrogen peroxide (CHP), activated persulfate (AP), and H2O2–persulfate (HP) co-amendment systems. Citrate, a buffer and iron ligand,...

  20. Comparative Study on Oxidative Treatments of NAPL Containing Chlorinated Ethanes and Ethenes using Hydrogen Peroxide and Persulfate in Soils

    EPA Science Inventory

    The goal of this study was to assess the oxidation of NAPL in soil, 30% of which were composed of chlorinated ethanes and ethenes, using catalyzed hydrogen peroxide (CHP), activated persulfate (AP), and H2O2–persulfate (HP) co-amendment systems. Citrate, a buffer and iron ligand,...

  1. Hydrogen Peroxide in Groundwater at Rifle, Colorado

    NASA Astrophysics Data System (ADS)

    Yuan, X.; Nico, P. S.; Williams, K. H.; Hobson, C.; Davis, J. A.

    2015-12-01

    Hydrogen peroxide (H2O2), as a reactive transient presenting ubiquitously in natural surface waters, can react with a large suite of biologically important and redox-sensitive trace elements. The dominant source of H2O2 in natural waters has long been thought to be photo-oxidation of chromophoric dissolved organic matter by molecular oxygen to produce superoxide radical, which then proceeds via dismutation to generate H2O2. However, recent studies have indicated that dark production of H2O2 in deep seawater, principally by biological production, is potentially on par with photochemical generation. Here, we present evidence for abiotic dark generation of H2O2 in groundwater in an alluvial aquifer adjacent to the Colorado River near Rifle, CO. Background H2O2 concentrations were determined in situ using a sensitive chemiluminescence-based method. Our results suggest H2O2 concentrations ranged from lower than the detection limit (1 nM) to 54 nM in different monitoring wells at the site, and the concentrations exhibited close correlations with profiles of dissolved oxygen and iron concentrations in the wells, indicating a possible metal redox cycling mechanism. In addition, dissolved natural organic matter, which could potentially coordinate the interconversion of ferric and ferrous species, might also play an important role in H2O2 formation. While biologically mediated activities have been recognized as the major sink of H2O2, the detected H2O2 pattern in groundwater suggests the existence of a balance between H2O2 source and decay, which potentially involves a cascade of biogeochemically significant processes, including the interconversion of ferrous/ferric species, the generation of more reactive oxygen species, such as hydroxyl radical, the depletion of dissolved oxygen and further transformation of natural organic matter and other chemical pollutants.

  2. Localised hydrogen peroxide sensing for reproductive health

    NASA Astrophysics Data System (ADS)

    Purdey, Malcolm S.; Schartner, Erik P.; Sutton-McDowall, Melanie L.; Ritter, Lesley J.; Thompson, Jeremy G.; Monro, Tanya M.; Abell, Andrew D.

    2015-05-01

    The production of reactive oxygen species (ROS) is known to affect the developmental competence of embryos. Hydrogen peroxide (H2O2) an important reactive oxygen species, is also known to causes DNA damage and defective sperm function. Current techniques require incubating a developing embryo with an organic fluorophore which is potentially hazardous for the embryo. What we need is a localised ROS sensor which does not require fluorophores in solution and hence will allow continuous monitoring of H2O2 production without adversely affect the development of the embryo. Here we report studies on such a fibre-based sensor for the detection of H2O2 that uses a surface-bound aryl boronate fluorophore carboxyperoxyfluor-1(CPF1). Optical fibres present a unique platform due to desirable characteristics as dip sensors in biological solutions. Attempts to functionalise the fibre tips using polyelectrolyte layers and (3-aminopropyl)triethoxysilane (APTES) coatings resulted in a limited signal and poor fluorescent response to H2O2 due to a low tip surface density of the fluorophore. To increase the surface density, CPF1 was integrated into a polymer matrix formed on the fibre tip by a UV-catalysed polymerisation process of acrylamide onto a methacrylate silane layer. The polyacrylamide containing CPF1 gave a much higher surface density than previous surface attachment methods and the sensor was found to effectively detect H2O2. Using this method, biologically relevant concentrations of H2O2 were detected, enabling remote sensing studies into ROS releases from embryos throughout early development.

  3. Recent Development in Hydrogen Peroxide Pumped Propulsion

    SciTech Connect

    Ledebuhr, A G; Antelman, D R; Dobie, D W; Gorman, T S; Jones, M S; Kordas, J F; McMahon, D H; Ng, L C; Nielsen, D P; Ormsby, A E; Pittenger, L C; Robinson, J A; Skulina, K M; Taylor, W G; Urone, D A; Wilson, B A

    2004-03-22

    This paper describes the development of a lightweight high performance pump-fed divert and attitude control system (DACS). Increased kinetic Kill Vehicles (KV) capabilities (higher .v and acceleration capability) will especially be needed for boost phase engagements where a lower mass KV DACS enables smaller overall interceptors. To increase KV performance while reducing the total DACS dry mass (<10 kg), requires a design approach that more closely emulates those found in large launch vehicles, where pump-fed propulsion enables high propellant-mass-fraction systems. Miniaturized reciprocating pumps, on a scale compatible with KV applications, offer the potential of a lightweight DACS with both high {Delta}v and acceleration capability, while still enabling the rapid pulsing of the divert thrusters needed in the end-game fly-in. Pumped propulsion uses lightweight low-pressure propellant tanks, as the main vehicle structure and eliminates the need for high-pressure gas bottles, reducing mass and increasing the relative propellant load. Prior work used hydrazine and demonstrated a propellant mass fraction >0.8 and a vehicle propulsion dry mass of {approx}3 kg. Our current approach uses the non-toxic propellants 90% hydrogen peroxide and kerosene. This approach enables faster development at lower costs due to the ease of handling. In operational systems these non-toxic propellants can simplify the logistics for manned environments including shipboard applications. This DACS design configuration is expected to achieve sufficient mass flows to support divert thrusters in the 1200 N to 1330 N (270 lbf to 300 lbf) range. The DACS design incorporates two pairs of reciprocating differential piston pumps (oxidizer and fuel), a warm-gas drive system, compatible bi-propellant thrusters, lightweight valves, and lightweight low-pressure propellant tanks. This paper summarizes the current development status and plans.

  4. Quantitative biology of hydrogen peroxide signaling.

    PubMed

    Antunes, Fernando; Brito, Paula Matos

    2017-10-01

    Hydrogen peroxide (H2O2) controls signaling pathways in cells by oxidative modulation of the activity of redox sensitive proteins denominated redox switches. Here, quantitative biology concepts are applied to review how H2O2 fulfills a key role in information transmission. Equations described lay the foundation of H2O2 signaling, give new insights on H2O2 signaling mechanisms, and help to learn new information from common redox signaling experiments. A key characteristic of H2O2 signaling is that the ratio between reduction and oxidation of redox switches determines the range of H2O2 concentrations to which they respond. Thus, a redox switch with low H2O2-dependent oxidability and slow reduction rate responds to the same range of H2O2 concentrations as a redox switch with high H2O2-dependent oxidability, but that is rapidly reduced. Yet, in the first case the response time is slow while in the second case is rapid. H2O2 sensing and transmission of information can be done directly or by complex mechanisms in which oxidation is relayed between proteins before oxidizing the final regulatory redox target. In spite of being a very simple molecule, H2O2 has a key role in cellular signaling, with the reliability of the information transmitted depending on the inherent chemical reactivity of redox switches, on the presence of localized H2O2 pools, and on the molecular recognition between redox switches and their partners. Copyright © 2017 The Authors. Published by Elsevier B.V. All rights reserved.

  5. RESULTS OF COPPER CATALYZED PEROXIDE OXIDATION (CCPO) OF TANK 48H SIMULANTS

    SciTech Connect

    Peters, T.; Pareizs, J.; Newell, J.; Fondeur, F.; Nash, C.; White, T.; Fink, S.

    2012-08-14

    Savannah River National Laboratory (SRNL) performed a series of laboratory-scale experiments that examined copper-catalyzed hydrogen peroxide (H{sub 2}O{sub 2}) aided destruction of organic components, most notably tetraphenylborate (TPB), in Tank 48H simulant slurries. The experiments were designed with an expectation of conducting the process within existing vessels of Building 241-96H with minimal modifications to the existing equipment. Results of the experiments indicate that TPB destruction levels exceeding 99.9% are achievable, dependent on the reaction conditions. The following observations were made with respect to the major processing variables investigated. A lower reaction pH provides faster reaction rates (pH 7 > pH 9 > pH 11); however, pH 9 reactions provide the least quantity of organic residual compounds within the limits of species analyzed. Higher temperatures lead to faster reaction rates and smaller quantities of organic residual compounds. Higher concentrations of the copper catalyst provide faster reaction rates, but the highest copper concentration (500 mg/L) also resulted in the second highest quantity of organic residual compounds. Faster rates of H{sub 2}O{sub 2} addition lead to faster reaction rates and lower quantities of organic residual compounds. Testing with simulated slurries continues. Current testing is examining lower copper concentrations, refined peroxide addition rates, and alternate acidification methods. A revision of this report will provide updated findings with emphasis on defining recommended conditions for similar tests with actual waste samples.

  6. Different Modes of Hydrogen Peroxide Action During Seed Germination.

    PubMed

    Wojtyla, Łukasz; Lechowska, Katarzyna; Kubala, Szymon; Garnczarska, Małgorzata

    2016-01-01

    Hydrogen peroxide was initially recognized as a toxic molecule that causes damage at different levels of cell organization and thus losses in cell viability. From the 1990s, the role of hydrogen peroxide as a signaling molecule in plants has also been discussed. The beneficial role of H2O2 as a central hub integrating signaling network in response to biotic and abiotic stress and during developmental processes is now well established. Seed germination is the most pivotal phase of the plant life cycle, affecting plant growth and productivity. The function of hydrogen peroxide in seed germination and seed aging has been illustrated in numerous studies; however, the exact role of this molecule remains unknown. This review evaluates evidence that shows that H2O2 functions as a signaling molecule in seed physiology in accordance with the known biology and biochemistry of H2O2. The importance of crosstalk between hydrogen peroxide and a number of signaling molecules, including plant phytohormones such as abscisic acid, gibberellins, and ethylene, and reactive molecules such as nitric oxide and hydrogen sulfide acting on cell communication and signaling during seed germination, is highlighted. The current study also focuses on the detrimental effects of H2O2 on seed biology, i.e., seed aging that leads to a loss of germination efficiency. The dual nature of hydrogen peroxide as a toxic molecule on one hand and as a signal molecule on the other is made possible through the precise spatial and temporal control of its production and degradation. Levels of hydrogen peroxide in germinating seeds and young seedlings can be modulated via pre-sowing seed priming/conditioning. This rather simple method is shown to be a valuable tool for improving seed quality and for enhancing seed stress tolerance during post-priming germination. In this review, we outline how seed priming/conditioning affects the integrative role of hydrogen peroxide in seed germination and aging.

  7. Different Modes of Hydrogen Peroxide Action During Seed Germination

    PubMed Central

    Wojtyla, Łukasz; Lechowska, Katarzyna; Kubala, Szymon; Garnczarska, Małgorzata

    2016-01-01

    Hydrogen peroxide was initially recognized as a toxic molecule that causes damage at different levels of cell organization and thus losses in cell viability. From the 1990s, the role of hydrogen peroxide as a signaling molecule in plants has also been discussed. The beneficial role of H2O2 as a central hub integrating signaling network in response to biotic and abiotic stress and during developmental processes is now well established. Seed germination is the most pivotal phase of the plant life cycle, affecting plant growth and productivity. The function of hydrogen peroxide in seed germination and seed aging has been illustrated in numerous studies; however, the exact role of this molecule remains unknown. This review evaluates evidence that shows that H2O2 functions as a signaling molecule in seed physiology in accordance with the known biology and biochemistry of H2O2. The importance of crosstalk between hydrogen peroxide and a number of signaling molecules, including plant phytohormones such as abscisic acid, gibberellins, and ethylene, and reactive molecules such as nitric oxide and hydrogen sulfide acting on cell communication and signaling during seed germination, is highlighted. The current study also focuses on the detrimental effects of H2O2 on seed biology, i.e., seed aging that leads to a loss of germination efficiency. The dual nature of hydrogen peroxide as a toxic molecule on one hand and as a signal molecule on the other is made possible through the precise spatial and temporal control of its production and degradation. Levels of hydrogen peroxide in germinating seeds and young seedlings can be modulated via pre-sowing seed priming/conditioning. This rather simple method is shown to be a valuable tool for improving seed quality and for enhancing seed stress tolerance during post-priming germination. In this review, we outline how seed priming/conditioning affects the integrative role of hydrogen peroxide in seed germination and aging. PMID:26870076

  8. Inhibition of porcine kidney betaine aldehyde dehydrogenase by hydrogen peroxide.

    PubMed

    Rosas-Rodríguez, Jesús A; Figueroa-Soto, Ciria G; Valenzuela-Soto, Elisa M

    2010-01-01

    Renal hyperosmotic conditions may produce reactive oxygen species, which could have a deleterious effect on the enzymes involved in osmoregulation. Hydrogen peroxide was used to provoke oxidative stress in the environment of betaine aldehyde dehydrogenase in vitro. Enzyme activity was reduced as hydrogen peroxide concentration was increased. Over 50% of the enzyme activity was lost at 100 μM hydrogen peroxide at two temperatures tested. At pH 8.0, under physiological ionic strength conditions, peroxide inhibited the enzyme. Initial velocity assays of betaine aldehyde dehydrogenase in the presence of hydrogen peroxide (0-200 μM) showed noncompetitive inhibition with respect to NAD(+) or to betaine aldehyde at saturating concentrations of the other substrate at pH 7.0 or 8.0. Inhibition data showed that apparent V(max) decreased 40% and 26% under betaine aldehyde and NAD(+) saturating concentrations at pH 8.0, while at pH 7.0 V(max) decreased 40% and 29% at betaine aldehyde and NAD(+) saturating concentrations. There was little change in apparent Km(NAD) at either pH, while Km(BA) increased at pH 7.0. K(i) values at pH 8 and 7 were calculated. Our results suggest that porcine kidney betaine aldehyde dehydrogenase could be inhibited by hydrogen peroxide in vivo, thus compromising the synthesis of glycine betaine.

  9. [Determination of hydrogen peroxide in rainwater by fluorometry].

    PubMed

    Fang, Yan-Fen; Huang, Ying-Ping; Luo, Guang-Fu; Li, Rui-Ping

    2008-04-01

    The present paper introduces a new method using spectrofluorimetric analysis to determine the concentration of hydrogen peroxide in rainwater. In this method, an oxidation reaction is conducted between o-phenylenediamine (OPDA) and hydrogen peroxide in the buffer medium of NaAc-HAc at pH 4. 48 to form a new product 2,3-diaminophenazine (DAPN). Then the fluorescence intensity of DAPN is measured and 426 and 554 nm are chosen as the excitation and emission wavelengths. Therefore, with the foreknown concentration of input hydrogen peroxide, a series of fluorescence intensities of DAPN are acquired according to a series of different concentration of hydrogen peroxide as input, greatly improving the selectivity and sensibility of the system. A relationship between the input concentration of hydrogen peroxide and the fluorescence intensity of DAPN is then obtained using a linear regression. Results show that fluorescence intensity of DAPN is in proportion to the increase in the concentration of hydrogen peroxide in the range of 9.0 x 10(-7) -3.56 x 10(-5) mol x L(-1) almost linearly. The linear equation is F = 1.15c (micromol x L(-1))+398.6 (r = 0.999 1) and the detection limit is 2.7 x10(-7) mol x L(-1) (n = 11). The relative standard deviation of 11 parallel measurements with the concentration of H2O2 at 7.5 x 10(-6) and 3.0 x 10(-5) mol x L(-1), is 2.2 and 1.0%, respectively. Results from DPD method was used to verify this method. The interference of foreign iron was studied. Compared to the traditional methods, this binary system has a simplified operation and high sensitivity. The proposed method has been successfully applied to determine the concentration of hydrogen peroxide in rainwater.

  10. Catalytic decomposition of hydrogen peroxide and 2-chlorophenol with iron oxides.

    PubMed

    Huang, H H; Lu, M C; Chen, J N

    2001-06-01

    The aim of this study was to examine the catalyzed decomposition of hydrogen peroxide and 2-chlorophenol (2-CP) in the presence of iron oxides. Granular ferrihydrite, goethite, and hematite were selected as catalysts in this study. 2-CP was used as the model compound because it is a typical toxic compound and has not been investigated in the catalytic decomposition by iron oxides. The catalytic activity for hydrogen peroxide decomposition followed the sequence: granular ferrihydrite > goethite > hematite. However, hematite exhibited the highest activity in catalyzing 2-CP oxidation. The oxidation efficiency of 2-CP corresponded with the inverse sequence of specific area and pHpzc of the iron oxides. The catalytic activity of granular ferrihydrite was affected significantly by the mixing speed and particle size for its large value of Thiele modulus (phi) and Damkohler number (Da). The strong diffusion resistance for granular ferrihydrite was attributed either to its microporous structure or to the formation of oxygen in the pores of the iron oxide leading to the unexpected catalytic activity of granular ferrihydrite to hydrogen peroxide and 2-CP.

  11. Improvement of adventitious root formation in flax using hydrogen peroxide.

    PubMed

    Takáč, Tomáš; Obert, Bohuš; Rolčík, Jakub; Šamaj, Jozef

    2016-09-25

    Flax (Linum usitatissimum L.) is an important crop for the production of oil and fiber. In vitro manipulations of flax are used for genetic improvement and breeding while improvements in adventitious root formation are important for biotechnological programs focused on regeneration and vegetative propagation of genetically valuable plant material. Additionally, flax hypocotyl segments possess outstanding morphogenetic capacity, thus providing a useful model for the investigation of flax developmental processes. Here, we investigated the crosstalk between hydrogen peroxide and auxin with respect to reprogramming flax hypocotyl cells for root morphogenetic development. Exogenous auxin induced the robust formation of adventitious roots from flax hypocotyl segments while the addition of hydrogen peroxide further enhanced this process. The levels of endogenous auxin (indole-3-acetic acid; IAA) were positively correlated with increased root formation in response to exogenous auxin (1-Naphthaleneacetic acid; NAA). Histochemical staining of the hypocotyl segments revealed that hydrogen peroxide and peroxidase, but not superoxide, were positively correlated with root formation. Measurements of antioxidant enzyme activities showed that endogenous levels of hydrogen peroxide were controlled by peroxidases during root formation from hypocotyl segments. In conclusion, hydrogen peroxide positively affected flax adventitious root formation by regulating the endogenous auxin levels. Consequently, this agent can be applied to increase flax regeneration capacity for biotechnological purposes such as improved plant rooting.

  12. Probing skin interaction with hydrogen peroxide using diffuse reflectance spectroscopy

    NASA Astrophysics Data System (ADS)

    Zonios, George; Dimou, Aikaterini; Galaris, Dimitrios

    2008-01-01

    Hydrogen peroxide is an important oxidizing agent in biological systems. In dermatology, it is frequently used as topical antiseptic, it has a haemostatic function, it can cause skin blanching, and it can facilitate skin tanning. In this work, we investigated skin interaction with hydrogen peroxide, non-invasively, using diffuse reflectance spectroscopy. We observed transient changes in the oxyhaemoglobin and deoxyhaemoglobin concentrations as a result of topical application of dilute H2O2 solutions to the skin, with changes in deoxyhaemoglobin concentration being more pronounced. Furthermore, we did not observe any appreciable changes in melanin absorption properties as well as in the skin scattering properties. We also found no evidence for production of oxidized haemoglobin forms. Our observations are consistent with an at least partial decomposition of hydrogen peroxide within the stratum corneum and epidermis, with the resulting oxygen and/or remaining hydrogen peroxide inducing vasoconstriction to dermal blood vessels and increasing haemoglobin oxygen saturation. An assessment of the effects of topical application of hydrogen peroxide to the skin may serve as the basis for the development of non-invasive techniques to measure skin antioxidant capacity and also may shed light onto skin related disorders such as vitiligo.

  13. 14 CFR 420.66 - Separation distance requirements for storage of hydrogen peroxide, hydrazine, and liquid hydrogen...

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... storage of hydrogen peroxide, hydrazine, and liquid hydrogen and any incompatible energetic liquids stored... Responsibilities of a Licensee § 420.66 Separation distance requirements for storage of hydrogen peroxide... section for each explosive hazard facility storing: (1) Hydrogen peroxide in concentrations of greater...

  14. 14 CFR 420.66 - Separation distance requirements for storage of hydrogen peroxide, hydrazine, and liquid hydrogen...

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... storage of hydrogen peroxide, hydrazine, and liquid hydrogen and any incompatible energetic liquids stored... Responsibilities of a Licensee § 420.66 Separation distance requirements for storage of hydrogen peroxide... section for each explosive hazard facility storing: (1) Hydrogen peroxide in concentrations of greater...

  15. Comparison of chemiluminescence methods for analysis of hydrogen peroxide and hydroxyl radicals

    NASA Astrophysics Data System (ADS)

    Pehrman, R.; Amme, M.; Cachoir, C.

    2006-01-01

    Assessment of alpha radiolysis influence on the chemistry of geologically disposed spent fuel demands analytical methods for radiolytic product determination at trace levels. Several chemiluminescence methods for the detection of radiolytic oxidants hydrogen peroxide and hydroxyl radicals are tested. Two of hydrogen peroxide methods use luminol, catalyzed by either μ-peroxidase or hemin, one uses 10-methyl-9-(p-formylphenyl)-acridinium carboxylate trifluoromethanesulfonate and one potassium periodate. All recipes are tested as batch systems in basic conditions. For hydroxyl radical detection luminophores selected are 3-hydroxyphthalic hydrazide and rutin. Both methods are tested as batch systems. The results are compared and the applicability of the methods for near-field dissolution studies is discussed.

  16. Fluorescent hydrogen peroxide sensor based on cupric oxide nanoparticles and its application for glucose and L-lactate detection.

    PubMed

    Hu, Ai-Ling; Liu, Yin-Huan; Deng, Hao-Hua; Hong, Guo-Lin; Liu, Ai-Lin; Lin, Xin-Hua; Xia, Xing-Hua; Chen, Wei

    2014-11-15

    A novel fluorescent hydrogen peroxide sensor was developed based on the peroxidase-like activity of cupric oxide nanoparticles. Cupric oxide nanoparticles effectively catalyzed the decomposition of hydrogen peroxide into hydroxyl radicals. Then terephthalic acid was oxidized by hydroxyl radical to form a highly fluorescent product. The linear range of hydrogen peroxide estimated to be 5.0 × 10(-6)-2.0 × 10(-4)M with a detection limit of 3.4 × 10(-7)M. Moreover, this detection system enabled the sensing of analytes which can enzymatically generate hydrogen peroxide. By coupling the oxidation of glucose or L-lactate catalyzed by their corresponding oxidase enzymes with terephthalic acid oxidation catalyzed by cupric oxide nanoparticles, sensitive assays of glucose and l-lactate with detection limits of 1.0 × 10(-6) and 4.5 × 10(-8)M were realized. The successful applications of this approach in human serum samples have also been demonstrated.

  17. Millimeter and sub-millimeter wave detection of hydrogen peroxide

    NASA Astrophysics Data System (ADS)

    Kolbe, W. F.; Leskovar, B.

    1987-08-01

    The measurement of small concentrations of hydrogen peroxide through the detection of rotational transitions in the millimeter and sub-millimeter wave regions is discussed. Calculated transition frequencies and absorption coefficients of H2O2 for frequencies up to 2000 GHz are presented. The reliability of the calculated values is illustrated by measurements of the linewidths and absorption coefficients of transitions in the 140 GHz range. Finally, methods for the detection of trace quantities of the peroxide molecule are briefly described.

  18. In vitro curcumin modulates ferric nitrilotriacetate (Fe-NTA) and hydrogen peroxide (H2O2)-induced peroxidation of microsomal membrane lipids and DNA damage.

    PubMed

    Iqbal, Mohammad; Okazaki, Yasumasa; Okada, Shigeru

    2003-01-01

    A number of investigations have implicated the involvement of free radicals in various pathogenic process including initiation/promotion stages of carcinogenesis and antioxidants have been considered to be a protective agent for this reason. An iron chelate, ferric nitrilotriacetate (Fe-NTA), is a potent nephrotoxic agent and induces acute and subacute renal proximal tubular necrosis by catalyzing the decomposition of hydrogen peroxide-derived production of hydroxyl radicals, which are known to cause lipid peroxidation and DNA damage. The latter is associated with a high incidence of renal adenocarcinoma in rodents. Lipid peroxidation and DNA damage are the principal manifestation of Fe-NTA-induced toxicity, which could be mitigated by antioxidants. In this study, we therefore investigated the effect of curcumin, a polyphenolic compound from Curcuma longa for a possible protection against lipid peroxidation and DNA damage induced by Fe-NTA and hydrogen peroxide in vitro. Incubation of renal microsomal membrane/and or calf thymus DNA with hydrogen peroxide (40 mM) in the presence of Fe-NTA (0.1 mM) induces renal microsomal lipid peroxidation and DNA damage to about 2.2-and 5.6-fold, respectively, as compared to saline treated control (P<0.001). Induction of renal microsomal lipid peroxidation and DNA damage was modulated by curcumin dose dependently. In lipid peroxidation protection studies, curcumin treatment showed a dose-dependent strong inhibition (18-80% inhibition, P<0.05-0.001) of Fe-NTA and hydrogen peroxide-induced lipid peroxidation as measured by MDA formation in renal microsomes. Similarly, in DNA-sugar damage protection studies, curcumin treatment also showed a dose dependent inhibition (22-57% inhibition, P<0.05-0.001) of DNA-sugar damage. From these studies, it was concluded that curcumin modulates Fe-NTA and hydrogen peroxide-induced peroxidation of microsomal membrane lipids and DNA damage. Curcumin might, therefore, be a suitable candidate for the

  19. Enhanced chemiluminescence of the luminol-hydrogen peroxide system by colloidal cupric oxide nanoparticles as peroxidase mimic.

    PubMed

    Chen, Wei; Hong, Lei; Liu, Ai-Lin; Liu, Jian-Qing; Lin, Xin-Hua; Xia, Xing-Hua

    2012-09-15

    As a peroxidase mimic, cupric oxide nanoparticles were found to enhance the chemiluminescence (CL) of luminol-H(2)O(2) system up to 400 folds. The CL spectra and radical scavengers were conducted to investigate the possible CL enhancement mechanism. It was suggested that the enhanced CL could be attributed to the peroxidase-like activity of CuO nanoparticles, which effectively catalyzed the decomposition of hydrogen peroxide into hydroxyl radicals. The effects of the reactant concentrations and some organic compounds were also investigated. The proposed method could be used as a sensitive detection tool for hydrogen peroxide and glucose.

  20. Selective electrochemical generation of hydrogen peroxide from water oxidation

    DOE PAGES

    Viswanathan, Venkatasubramanian; Hansen, Heine A.; Norskov, Jens K.

    2015-10-08

    Water is a life-giving source, fundamental to human existence, yet over a billion people lack access to clean drinking water. The present techniques for water treatment such as piped, treated water rely on time and resource intensive centralized solutions. In this work, we propose a decentralized device concept that can utilize sunlight to split water into hydrogen and hydrogen peroxide. The hydrogen peroxide can oxidize organics while the hydrogen bubbles out. In enabling this device, we require an electrocatalyst that can oxidize water while suppressing the thermodynamically favored oxygen evolution and form hydrogen peroxide. Using density functional theory calculations, wemore » show that the free energy of adsorbed OH* can be used to determine selectivity trends between the 2e– water oxidation to H2O2 and the 4e– oxidation to O2. We show that materials which bind oxygen intermediates sufficiently weakly, such as SnO2, can activate hydrogen peroxide evolution. Furthermore, we present a rational design principle for the selectivity in electrochemical water oxidation and identify new material candidates that could perform H2O2 evolution selectively.« less

  1. Selective electrochemical generation of hydrogen peroxide from water oxidation

    SciTech Connect

    Viswanathan, Venkatasubramanian; Hansen, Heine A.; Norskov, Jens K.

    2015-10-08

    Water is a life-giving source, fundamental to human existence, yet over a billion people lack access to clean drinking water. The present techniques for water treatment such as piped, treated water rely on time and resource intensive centralized solutions. In this work, we propose a decentralized device concept that can utilize sunlight to split water into hydrogen and hydrogen peroxide. The hydrogen peroxide can oxidize organics while the hydrogen bubbles out. In enabling this device, we require an electrocatalyst that can oxidize water while suppressing the thermodynamically favored oxygen evolution and form hydrogen peroxide. Using density functional theory calculations, we show that the free energy of adsorbed OH* can be used to determine selectivity trends between the 2e– water oxidation to H2O2 and the 4e– oxidation to O2. We show that materials which bind oxygen intermediates sufficiently weakly, such as SnO2, can activate hydrogen peroxide evolution. Furthermore, we present a rational design principle for the selectivity in electrochemical water oxidation and identify new material candidates that could perform H2O2 evolution selectively.

  2. A MEMS methanol reformer heated by decomposition of hydrogen peroxide.

    PubMed

    Kim, Taegyu; Hwang, Jin Soo; Kwon, Sejin

    2007-07-01

    This paper presents the design, fabrication and evaluation of a micro methanol reformer complete with a heat source. The micro system consists of the steam reforming reactor of methanol, the catalytic decomposition reactor of hydrogen peroxide, and a heat exchanger between the two reactors. In the present study, catalytic decomposition of hydrogen peroxide is used as a process to supply heat to the reforming reactor. The decomposition process of hydrogen peroxide produces water vapor and oxygen as a product that can be used efficiently to operate the reformer/PEMFC system. Cu/ZnO was selected as a catalyst for methanol steam reforming and Pt for the decomposition of hydrogen peroxide. Incipient wetness method was used to load catalysts on a porous support. Catalyst loaded supports were inserted in the cavity made on the glass wafer. The performance of the methanol steam reforming system was measured at various test conditions and the optimum operation condition was sought. At the optimum condition, the hydrogen selectivity was 86.4% and the thermal efficiency was 44.8%. The product gas included 74.1% H(2), 24.5% CO(2) and 1.4% CO and the total volume production rate was 23.5 ml min(-1). This amount of hydrogen can produce 1.5 W of power on a typical PEMFC.

  3. Simulated afterburner performance with hydrogen peroxide injection for thrust augmentation

    NASA Technical Reports Server (NTRS)

    Metzler, Allen J; Grobman, Jack S

    1956-01-01

    Combustion performance of three afterburner configurations was evaluated at simulated altitude flight conditions with liquid augmentation to the primary combustor. Afterburner combustion efficiency and stability were better with injection of high-strength hydrogen peroxide than with no injection or with water injection. Improvements were observed in afterburner configurations with and without flameholders and in a short-length afterburner. At a peroxide-air ratio of 0.3, combustion was stable and 85 to 90 percent efficient in all configurations tested. Calculated augmented net-thrust ratios for peroxide injection with afterburning were approximately 60 percent greater than those for water injection.

  4. Cathodic electrocatalyst layer for electrochemical generation of hydrogen peroxide

    NASA Technical Reports Server (NTRS)

    Rhodes, Christopher P. (Inventor); Tennakoon, Charles L. K. (Inventor); Singh, Waheguru Pal (Inventor); Anderson, Kelvin C. (Inventor)

    2011-01-01

    A cathodic gas diffusion electrode for the electrochemical production of aqueous hydrogen peroxide solutions. The cathodic gas diffusion electrode comprises an electrically conductive gas diffusion substrate and a cathodic electrocatalyst layer supported on the gas diffusion substrate. A novel cathodic electrocatalyst layer comprises a cathodic electrocatalyst, a substantially water-insoluble quaternary ammonium compound, a fluorocarbon polymer hydrophobic agent and binder, and a perfluoronated sulphonic acid polymer. An electrochemical cell using the novel cathodic electrocatalyst layer has been shown to produce an aqueous solution having between 8 and 14 weight percent hydrogen peroxide. Furthermore, such electrochemical cells have shown stable production of hydrogen peroxide solutions over 1000 hours of operation including numerous system shutdowns.

  5. Catalytic wet hydrogen peroxide oxidation of a petrochemical wastewater.

    PubMed

    Pariente, M I; Melero, J A; Martínez, F; Botas, J A; Gallego, A I

    2010-01-01

    Continuous Catalytic Wet Hydrogen Peroxide Oxidation (CWHPO) for the treatment of a petrochemical industry wastewater has been studied on a pilot plant scale process. The installation, based on a catalytic fixed bed reactor (FBR) coupled with a stirred tank reactor (STR), shows an interesting alternative for the intensification of a continuous CWHPO treatment. Agglomerated SBA-15 silica-supported iron oxide (Fe(2)O(3)/SBA-15) was used as Fenton-like catalyst. Several variables such as the temperature and hydrogen peroxide concentration, as well as the capacity of the pilot plant for the treatment of inlet polluted streams with different dilution degrees were studied. Remarkable results in terms of TOC reduction and increased biodegradability were achieved using 160 degrees C and moderate hydrogen peroxide initial concentration. Additionally, a good stability of the catalyst was evidenced for 8 hours of treatment with low iron leaching (less than 1 mg/L) under the best operating conditions.

  6. Paraquat toxicity and effect of hydrogen peroxide on thermophilic bacteria.

    PubMed

    Allgood, G S; Perry, J J

    1985-01-01

    Paraquat (PQ++) increased cyanide-resistant univalent respiration in cell suspensions of five strains of obligately thermophilic bacteria. PQ++ was reduced by an NADH: or NADPH:paraquat diaphorase and selectivity for NADH, NADPH, or both electron donors varied among the thermophiles. Superoxide anion production that was dependent on the presence of PQ++ was shown by following the superoxide dismutase-inhibitable reduction of cytochrome c. In addition, the PQ++-dependent formation of hydrogen peroxide from superoxide anion was evident in two of the thermophilic strains. Catalase synthesis was induced by adding hydrogen peroxide to the growth medium of the thermophiles. The induction of catalase to eliminate hydrogen peroxide appears to be an important response of these thermophilic bacteria to oxygen toxicity.

  7. Hydrogen peroxide sensor using laser grade dye Rhodamine B

    NASA Astrophysics Data System (ADS)

    Pattanaik, Amitansu; Sahare, P. D.; Nanda, Maitreyee

    2007-11-01

    Many chemical sensors based on fluorescence spectroscopy have been reported in applications, ranging from biomedical and environmental monitoring to industrial process control. In these diverse applications, the analyte can be probed directly, by measuring its intrinsic absorption, or by incorporating some transduction mechanism such as reagent chemistry to enhance sensitivity and selectivity. Hydrogen Peroxide is a colorless liquid. It is a common oxidizing and bleaching agent. It plays an important role in High Power Laser such as Chemical Oxygen Iodine Laser (COIL). As it is on the Hazardous substance list and on the special health hazard substance list, detection of Hydrogen Peroxide is of great importance. In the present study the detection of hydrogen Peroxide is by fluorescence quenching of laser grade dye Rhodamine B. Estimation of rate constant of the bimolecular quenching reaction is made.

  8. Advanced oxidation of natural organic matter using hydrogen peroxide and iron-coated pumice particles.

    PubMed

    Kitis, M; Kaplan, S S

    2007-08-01

    The oxidative removal of natural organic matter (NOM) from waters using hydrogen peroxide and iron-coated pumice particles as heterogeneous catalysts was investigated. Two NOM sources were tested: humic acid solution and a natural source water. Iron coated pumice removed about half of the dissolved organic carbon (DOC) concentration at a dose of 3000 mg l(-1) in 24 h by adsorption only. Original pumice and peroxide dosed together provided UV absorbance reductions as high as 49%, mainly due to the presence of metal oxides including Al(2)O(3), Fe(2)O(3) and TiO(2) in the natural pumice, which are known to catalyze the decomposition of peroxide forming strong oxidants. Coating the original pumice particles with iron oxides significantly enhanced the removal of NOM with peroxide. A strong linear correlation was found between iron contents of coated pumices and UV absorbance reductions. Peroxide consumption also correlated with UV absorbance reduction. Control experiments proved the effective coating and the stability of iron oxide species bound on pumice surfaces. Results overall indicated that in addition to adsorptive removal of NOM by metal oxides on pumice surfaces, surface reactions between iron oxides and peroxide result in the formation of strong oxidants, probably like hydroxyl radicals, which further oxidize both adsorbed NOM and remaining NOM in solution, similar to those in Fenton-like reactions.

  9. Hydrogen Peroxide Gas Generator Cycle with a Reciprocating Pump

    SciTech Connect

    Whitehead, J C

    2002-06-11

    A four-chamber piston pump is powered by decomposed 85% hydrogen peroxide. The performance envelope of the evolving 400 gram pump has been expanded to 172 cc/s water flow at discharge pressures near 5 MPa. A gas generator cycle system using the pump has been tested under similar conditions of pressure and flow. The powerhead gas is derived from a small fraction of the pumped hydrogen peroxide, and the system starts from tank pressures as low as 0.2 MPa. The effects of steam condensation on performance have been evaluated.

  10. Ultrafast shock initiation of exothermic chemistry in hydrogen peroxide.

    PubMed

    Armstrong, Michael R; Zaug, Joseph M; Goldman, Nir; Kuo, I-Feng W; Crowhurst, Jonathan C; Howard, W Michael; Carter, Jeffrey A; Kashgarian, Michaele; Chesser, John M; Barbee, Troy W; Bastea, Sorin

    2013-12-12

    We report observations of shock compressed, unreacted hydrogen peroxide at pressures up to the von Neumann pressure for a steady detonation wave, using ultrafast laser-driven shock wave methods. At higher laser drive energy we find evidence of exothermic chemical reactivity occurring in less than 100 ps after the arrival of the shock wave in the sample. The results are consistent with our MD simulations and analysis and suggest that reactivity in hydrogen peroxide is initiated on a sub-100 ps time scale under conditions found just subsequent to the lead shock in a steady detonation wave.

  11. Effect of carbamide peroxide and hydrogen peroxide on the surface morphology and zinc oxide levels of IRM fillings.

    PubMed

    Rostein, I; Cohenca, N; Mor, C; Moshonov, J; Stabholz, A

    1995-12-01

    The effect of 10% carbamide peroxide or 10% hydrogen peroxide on the surface morphology and zinc oxide levels of IRM fillings was tested. Ninety IRM samples were treated with either 10% carbamide peroxide, 10% hydrogen peroxide or phosphate buffer which served as control. Treatment consisted of placing the samples in a dry incubator at 37 degrees C for 1, 3 or 7 days. At each time point, the samples were removed from the test solutions, dried and prepared for surface scanning electron microscopy and energy dispersive spectrometric analysis. After 3 days, 10% carbamide peroxide significantly reduced the zinc oxide levels as compared to the 10% hydrogen peroxide group (<0.01) and the controls (p<0.01). 10% hydrogen peroxide reduced the zinc oxide levels similarly to the control. No significant changes in the zinc oxide levels were found between 3 and 7 days in any of the groups tested. Microscopy examination of the carbamide peroxide group revealed granular surface with well defined crystalline areas. In the hydrogen peroxide group, numerous cracks with multiple sun burst-like areas were found. At the macroscopic level, the samples of this group appeared cracked and more swollen, as compared to controls and samples treated with carbamide peroxide. In conclusion, both 10% carbamide peroxide and 10% hydrogen peroxide altered the surface morphology and the zinc oxide levels of IRM fillings, but their modes of action differed.

  12. Oxidation of Disulfides to Thiolsulfinates with Hydrogen Peroxide and a Cyclic Seleninate Ester Catalyst.

    PubMed

    McNeil, Nicole M R; McDonnell, Ciara; Hambrook, Miranda; Back, Thomas G

    2015-06-11

    Cyclic seleninate esters function as mimetics of the antioxidant selenoenzyme glutathione peroxidase. They catalyze the reduction of harmful peroxides with thiols, which are converted to disulfides in the process. The possibility that the seleninate esters could also catalyze the further oxidation of disulfides to thiolsulfinates and other overoxidation products under these conditions was investigated. This has ramifications in potential medicinal applications of seleninate esters because of the possibility of catalyzing the unwanted oxidation of disulfide-containing spectator peptides and proteins. A variety of aryl and alkyl disulfides underwent facile oxidation with hydrogen peroxide in the presence of catalytic benzo-1,2-oxaselenolane Se-oxide affording the corresponding thiolsulfinates as the principal products. Unsymmetrical disulfides typically afforded mixtures of regioisomers. Lipoic acid and N,N'-dibenzoylcystine dimethyl ester were oxidized readily under similar conditions. Although isolated yields of the product thiolsulfinates were generally modest, these experiments demonstrate that the method nevertheless has preparative value because of its mild conditions. The results also confirm the possibility that cyclic seleninate esters could catalyze the further undesired oxidation of disulfides in vivo.

  13. Rh-Catalyzed Asymmetric Hydrogenation of 1,2-Dicyanoalkenes.

    PubMed

    Li, Meina; Kong, Duanyang; Zi, Guofu; Hou, Guohua

    2017-01-06

    A highly efficient enantioselective hydrogenation of 1,2-dicyanoalkenes catalyzed by the complex of rhodium and f-spiroPhos has been developed. A series of 1,2-dicyanoalkenes were successfully hydrogenated to the corresponding chiral 1,2-dicyanoalkanes under mild conditions with excellent enantioselectivities (up to 98% ee). This methodology provides efficient access to the asymmetric synthesis of chiral diamines.

  14. Distillation Kinetics of Solid Mixtures of Hydrogen Peroxide and Water and the Isolation of Pure Hydrogen Peroxide in Ultrahigh Vacuum

    NASA Technical Reports Server (NTRS)

    Teolis, B. D.; Baragiola, R. A.

    2006-01-01

    We present results of the growth of thin films of crystalline H2O2 and H2O2.2H2O (dihydrate) in ultrahigh vacuum by distilling an aqueous solution of hydrogen peroxide. We traced the process using infrared reflectance spectroscopy, mass loss on a quartz crystal microbalance, and in a few cases ultraviolet-visible reflectance. We find that the different crystalline phases-water, dihydrate, and hydrogen peroxide-have very different sublimation rates, making distillation efficient to isolate the less volatile component, crystalline H2O2.

  15. Enhancement of polyacrylamide gel slice dissolution in hydrogen peroxide by cupric sulfate.

    PubMed

    Donato, H; Doig, M T; Priest, D G

    1988-04-01

    An improved method is described for quantitation of radio-labelled protein by scintillation counting after polyacrylamide gel electrophoresis. The method is based upon copper catalyzed dissolution of gel slices in hydrogen peroxide under ambient conditions. Complete dissolution of gel sections was accomplished by incubation at 25 degrees C in 30% H2O2 that contained 0.9 mM CuSO4. Recovery of tritiated protein was greater than 90% under these conditions while in the absence of CuSO4 recovery was less than 50%.

  16. The criteria of critical runaway and stable temperatures of catalytic decomposition of hydrogen peroxide in the presence of hydrochloric acid.

    PubMed

    Lu, Kai-Tai; Yang, Ching-Chyuan; Lin, Peng-Chu

    2006-07-31

    The hydrogen peroxide and hydrochloric acid are used in close proximity in the computer chip manufacture. The hydrochloric acid catalyzes an exothermic decomposition of hydrogen peroxide into oxygen and water. The accumulation of heat and non-condensable gas increases temperature and pressure in this reaction process always lead to runaway reaction and accident owing to inadvertent mixing. Thus, the chemical reaction hazard has to be clearly identified. Its critical runaway temperatures and unstable reaction criteria in this reaction process have to be determined urgently. In this investigation, we estimated its kinetic parameters at various volumetric ratios of the hydrogen peroxide to hydrochloric acid. Then, used these kinetic parameters to evaluate their critical temperatures and stable criteria in each reaction processes. The analytic results are important and useful for the design of safety system in the computer chip manufacture.

  17. Bu4NI-catalyzed direct α-oxyacylation of diarylethanones with acyl peroxides.

    PubMed

    Zhou, Zhou; Cheng, Jiang; Yu, Jin-Tao

    2015-10-14

    The Bu4NI-catalyzed α-oxyacylation of diarylethanones with acyl peroxides is developed. The reaction is conducted at room temperature without metal catalysts and tolerates a series of functional groups leading to α-oxyacylated diarylethanones in moderate to good yields.

  18. Palladium-catalyzed decarboxylative ortho-arylation of 2-pyridyl sulfoxides with benzoyl peroxides.

    PubMed

    Sun, Meng; Wang, Zhe; Wang, Jiaxin; Guo, Peiyu; Chen, Xiangxiang; Li, Ya-Min

    2016-12-07

    A palladium catalyzed efficient strategy for regio-selective ortho-arylation of sulfoxides with benzoyl peroxides via decarboxylation has been developed. This reaction proceeds smoothly, tolerates a variety of functional groups, and provides easy access to the synthesis of different biaryl compounds.

  19. Oxygen K-shell excitation spectroscopy of hydrogen peroxide

    NASA Astrophysics Data System (ADS)

    Rühl, E.; Hitchcock, A. P.

    1991-07-01

    The absolute oscillator strength spectrum for oxygen K-shell excitation of hydrogen peroxide has been derived from electron energy loss spectra recorded under electric dipole scattering conditions. The spectrum is dominated by an intense low-lying excitation to the {O 1s -1, σ* (OO)} state at 533.0 eV. The spectrum is compared to the O 1 s spectra of bis (trifluoromethyl) peroxide and bis( t-butyl)peroxide. The spectra of all three peroxides exhibit a strong transition around 533 eV which involves O 1s promotions to an orbital of largely σ* (OO) character. The bond length-σ* resonance energy correlation and its relation to near-edge X-ray absorption fine structure (NEXAFS) determinations of the geometry of O 2 adsorbed on various metal surfaces is explored.

  20. Quantifying intracellular hydrogen peroxide perturbations in terms of concentration

    PubMed Central

    Huang, Beijing K.; Sikes, Hadley D.

    2014-01-01

    Molecular level, mechanistic understanding of the roles of reactive oxygen species (ROS) in a variety of pathological conditions is hindered by the difficulties associated with determining the concentration of various ROS species. Here, we present an approach that converts fold-change in the signal from an intracellular sensor of hydrogen peroxide into changes in absolute concentration. The method uses extracellular additions of peroxide and an improved biochemical measurement of the gradient between extracellular and intracellular peroxide concentrations to calibrate the intracellular sensor. By measuring peroxiredoxin activity, we found that this gradient is 650-fold rather than the 7–10-fold that is widely cited. The resulting calibration is important for understanding the mass-action kinetics of complex networks of redox reactions, and it enables meaningful characterization and comparison of outputs from endogenous peroxide generating tools and therapeutics across studies. PMID:25460730

  1. Hydrogen peroxide as a fungicide for fish culture

    USGS Publications Warehouse

    Dawson, V.K.; Rach, J.J.; Schreier, T.M.

    1994-01-01

    Antifungal agents are needed to maintain healthy stocks of fish in the intensive culture systems currently employed in fish hatcheries. Malachite green has been the most widely used antifungal agent; however, its potential for producing teratology in animals and fish precludes further use in fish culture. Preliminary studies at the National Fisheries Research Center, La Crosse, WI, USA (La Crosse Center) indicate that hydrogen peroxide is effective for control of Saprolegnia sp. fungus on incubating eggs of rainbow trout. It is also effective against a wide variety of other organisms such as bacteria, yeasts, viruses, and spores, and has been proposed as a treatment for sea lice on salmon. Hydrogen peroxide and its primary decomposition products, oxygen and water, are not systemic poisons and are considered environmentally compatible. In response to a petition from the La Crosse Center, the U.S. Food and Drug Administration (FDA) recently classified hydrogen peroxide as a 'low regulatory priority' when used for control of fungus on fish and fish eggs. Preliminary tests conducted at the La Crosse Center suggest that prophylactic treatments of 250 to 500 ppm (based on 100% active ingredient) for 15 minutes every other day will inhibit fungal infections on healthy rainbow trout (Oncorhynchus mykiss) eggs. This treatment regime also seems to inhibit fungal development and increase hatching success among infected eggs. Efficacy and safety of hydrogen peroxide as a fungicide for fish are currently being evaluated.

  2. Effect of hydrogen peroxide on human tendon allograft.

    PubMed

    Gardner, E M H; VonderHeide, N; Fisher, R; Brooker, G; Yates, P J

    2013-12-01

    Bacterial contamination of tendon allografts at the completion of processing has historically been about 2 %, with tendons that are found to be culture positive being discarded. Treatment of tendon allograft with hydrogen peroxide at the beginning of tissue processing may reduce bacterial contamination, however, the potential side effects of hydrogen peroxide treatment include hydrolysis of the collagen and this may alter the mechanical properties of the graft. Pairs of human tendons were used. One was washed in 3 % hydrogen peroxide for 5 min and the untreated tendon was used as a control. The ultimate tensile strength of the tendons was determined using a material testing machine. A freeze clamp technique was used to hold the tendons securely at the high loads required to cause tendon failure. There was no statistical difference in the ultimate tensile strength between the treated and untreated tendons. Mean strength ranged from Extensor Hallucis Longus at 588 Newtons to Tibialis Posterior at 2,366 Newtons. Hydrogen peroxide washing may reduce bacterial contamination of tendon allograft and does not affect the strength of the tendon.

  3. Evaluation of a new hydrogen peroxide wipe disinfectant.

    PubMed

    Boyce, John M; Havill, Nancy L

    2013-05-01

    A new activated hydrogen peroxide wipe disinfectant was used to disinfect 10 high-touch surfaces in 72 patient rooms. After cleaning, 99% of surfaces yielded less than 2.5 colony-forming units/cm(2), 75% yielded no growth, and 70% yielded adenosine triphosphate counts of less than 250 relative light units. The new disinfectant was highly effective.

  4. Polyhexanide and hydrogen peroxide inhibit proteoglycan synthesis of human chondrocytes.

    PubMed

    Röhner, Eric; Hoff, Paula; Winkler, Tobias; von Roth, Philipp; Seeger, Jörn Bengt; Perka, Carsten; Matziolis, Georg

    2011-03-01

    The use of local antiseptics is a common method in septic joint surgery. We tested polyhexanide and hydrogen peroxide, two of the most frequently used antiseptics with high efficacy and low toxicity. The purpose of this study was to evaluate the effects of both antiseptics on the extracellular cartilaginous matrix synthesis of human chondrocytes. Chondrocytes were isolated from donated human knee joints, embedded in alginate beads, and incubated for 10 and 30 minutes with polyhexanide (0.04%), hydrogen peroxide (3%), or phosphate-buffered saline (PBS) for control. Cartilaginous matrix production was quantified through light microscopic analysis of Alcian blue staining. Cell number and morphology were detected by histological analysis. Chondrocytes showed a decreased intensity of blue colouring after antiseptic treatment versus PBS. In contrast to that, neither the cell number per view field nor the cell morphology differed between the groups. Polyhexanide has more toxic potential than hydrogen peroxide. Based on the fact that the cell number and morphology was not altered by the substances at the examined concentrations, the lower intensity of Alcian blue staining of treated chondrocytes indicates a decreased cartilage-specific matrix synthesis by polyhexanide more than by hydrogen peroxide and control.

  5. Establishment of a Vaporous Hydrogen Peroxide Bio-Decontamination Capability

    DTIC Science & Technology

    2007-02-01

    strips that were exposed to vaporous hydrogen peroxide and a positive control BI strip were transferred aseptically to 10 ml Trypticase soya broth (TSB...that were exposed to VHP (10 locations) and a positive control BI strip from each manufacturer were transferred aseptically to 10ml Trypticase soya

  6. Hydrogen peroxide evolution during V-UV photolysis of water.

    PubMed

    Azrague, Kamal; Bonnefille, Eric; Pradines, Vincent; Pimienta, Véronique; Oliveros, Esther; Maurette, Marie-Thérèse; Benoit-Marquié, Florence

    2005-05-01

    Hydrogen peroxide evolution during the vacuum-ultraviolet (V-UV, 172 nm) photolysis of water is considerably affected by the presence of oxalic acid (employed as a model water pollutant) and striking differences are observed in the absence and in the presence of dioxygen.

  7. Oxygen Mass Flow Rate Generated for Monitoring Hydrogen Peroxide Stability

    NASA Technical Reports Server (NTRS)

    Ross, H. Richard

    2002-01-01

    Recent interest in propellants with non-toxic reaction products has led to a resurgence of interest in hydrogen peroxide for various propellant applications. Because peroxide is sensitive to contaminants, material interactions, stability and storage issues, monitoring decomposition rates is important. Stennis Space Center (SSC) uses thermocouples to monitor bulk fluid temperature (heat evolution) to determine reaction rates. Unfortunately, large temperature rises are required to offset the heat lost into the surrounding fluid. Also, tank penetration to accomodate a thermocouple can entail modification of a tank or line and act as a source of contamination. The paper evaluates a method for monitoring oxygen evolution as a means to determine peroxide stability. Oxygen generation is not only directly related to peroxide decomposition, but occurs immediately. Measuring peroxide temperature to monitor peroxide stability has significant limitations. The bulk decomposition of 1% / week in a large volume tank can produce in excess of 30 cc / min. This oxygen flow rate corresponds to an equivalent temperature rise of approximately 14 millidegrees C, which is difficult to measure reliably. Thus, if heat transfer were included, there would be no temperature rise. Temperature changes from the surrounding environment and heat lost to the peroxide will also mask potential problems. The use of oxygen flow measurements provides an ultra sensitive technique for monitoring reaction events and will provide an earlier indication of an abnormal decomposition when compared to measuring temperature rise.

  8. Toxicity of hydrogen peroxide treatments to rainbow trout eggs

    USGS Publications Warehouse

    Gaikowski, M.P.; Rach, J.J.; Olson, J.J.; Ramsay, R.T.

    1998-01-01

    Hydrogen peroxide treatments of 0, 500, 1,000, and 3,000 I?L/L, concentrations that were multiples of the Low Regulatory Priority limit of 500 I?L/L, were administered for 15 min every weekday (Mondaya??Friday) to eggs of rainbow trout Oncorhynchus mykiss and steelhead (anadromous rainbow trout) to determine the margin of safety existing for standard egg treatments. All untreated and treated eggs remained free of fungal infection throughout incubation. Hydrogen peroxide treatment reduced the mean percent hatch of rainbow trout eggs by 1.4a??5.9% among those treated at 500 I?L/L, 6.8a??15.4% among those treated at 1,000 I?L/L, and 13.2a??25.3% among those treated at 3,000 I?L/L. Mean percent hatch of rainbow trout eggs treated at 1,000 I?L H2O2/L was 7% lower than that for eggs treated at 500 I?L H2O2/L. Mean percent hatch of Skamania strain steelhead was significantly reduced by hydrogen peroxide treatment, whereas the mean percent hatch of Ganaraska strain steelhead was similar to the mean percent hatch of rainbow trout eggs. Daily percent mortality of rainbow trout eggs increased significantly from day 6 to day 10 (78a??135 daily temperature units, DTUsA?C) of incubation. Discontinuing hydrogen peroxide treatments to Skamania strain steelhead eggs from day 7 to day 11 (78a??105 DTUsA?C) of incubation significantly increased the probability of eggs reaching the eyed egg stage. The mean percent hatch of rainbow trout eggs treated with hydrogen peroxide at concentrations up to 1,000 I?L/L may be increased if no treatments are administered between 70 and 140 DTUsA?C. Mortality of sac fry was not observed at hydrogen peroxide concentrations of 1,000 I?L/L or lower. Fish culturists should be aware that other species or strains may be more sensitive than rainbow trout. Other species and strains should be initially treated with hydrogen peroxide at 500 I?L/L until monitoring of egg mortality identifies the presence or absence of a sensitive period.

  9. 78 FR 73697 - New Animal Drugs; Hyaluronate Sodium; Hydrogen Peroxide; Imidacloprid and Moxidectin; Change of...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-12-09

    ...; Hyaluronate Sodium; Hydrogen Peroxide; Imidacloprid and Moxidectin; Change of Sponsor AGENCY: Food and Drug... interest in, NADA 141-255 for PEROX-AID (hydrogen peroxide) 35% Solution to Western Chemical, Inc.,...

  10. 21 CFR 172.167 - Silver nitrate and hydrogen peroxide solution.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... Hydrogen Peroxide Test Kit from the HACH Co., or equivalent. The manual from the Hydrogen Peroxide Test Kit... may obtain copies of the test kit manual from the HACH Co., P.O. Box 389, Loveland CO, 80359...

  11. 21 CFR 172.167 - Silver nitrate and hydrogen peroxide solution.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... Hydrogen Peroxide Test Kit from the HACH Co., or equivalent. The manual from the Hydrogen Peroxide Test Kit... may obtain copies of the test kit manual from the HACH Co., P.O. Box 389, Loveland CO, 80359...

  12. Hydrogen peroxide oxidant fuel cell systems for ultra-portable applications

    NASA Technical Reports Server (NTRS)

    Valdez, T. I.; Narayanan, S. R.

    2001-01-01

    This paper will address the issues of using hydrogen peroxide as an oxidant fuel in a miniature DMFC system. Cell performance for DMFC based fuel cells operating on hydrogen peroxide will be presented and discussed.

  13. Hydrogen peroxide oxidant fuel cell systems for ultra-portable applications

    NASA Technical Reports Server (NTRS)

    Valdez, T. I.; Narayanan, S. R.

    2001-01-01

    This paper will address the issues of using hydrogen peroxide as an oxidant fuel in a miniature DMFC system. Cell performance for DMFC based fuel cells operating on hydrogen peroxide will be presented and discussed.

  14. The First Characterization of Free Radicals Formed From Cellular COX-Catalyzed Peroxidation

    PubMed Central

    Gu, Yan; Xu, Yi; Law, Benedict; Qian, Steven Y.

    2014-01-01

    Through free radical-mediated peroxidation, cyclooxygenase (COX) can metabolize dihomo-γ-linolenic acid (DGLA) and arachidonic acid(AA) to form well-known bioactive metabolites, namely, the 1-series of prostaglandins (PGs1) and 2-series of prostaglandins(PGs2), respectively. Unlike PGs2, which are generally viewed as pro-inflammatory and pro-carcinogenic PGs, PGs1 may possess anti-inflammatory and anti-cancer activity. Previous studies using ovine COX along with spin trapping and the LC/ESR/MS technique have shown that certain exclusive free radicals are generated from different free radical reactions in DGLA and AA peroxidation. However, it has been unclear whether the differences were associated with the contrasting bioactivity of DGLA vs. AA. The aim of this study was to refine the LC/MS and spin-trapping technique to make it possible for the association between free radicals and cancer cell growth to be directly tested. Using a colon cancer cell line, HCA-7 colony 29, and LC/MS along with a solid phase extraction, we were able to characterize the reduced forms of radical adducts (hydroxylamines) as the free radicals generated from cellular COX-catalyzed peroxidation. For the first time, free radicals formed in the COX-catalyzed peroxidation of AA vs. DGLA and their association with cancer cell growth was assessed (cell proliferation via MTS and cell cycle distribution via PI staining) in the same experimental setting. The exclusive free radicals formed from the COX-catalyzed peroxidation of AA and DGLA were shown to be correlated with the cell growth response. Our results indicate that free radicals generated from the distinct radical reactions in COX-catalyzed peroxidation may represent the novel metabolites of AA and DGLA that correspond to their contrasting bioactivity. PMID:23261941

  15. The first characterization of free radicals formed from cellular COX-catalyzed peroxidation.

    PubMed

    Gu, Yan; Xu, Yi; Law, Benedict; Qian, Steven Y

    2013-04-01

    Through free radical-mediated peroxidation, cyclooxygenase (COX) can metabolize dihomo-γ-linolenic acid (DGLA) and arachidonic acid (AA) to form well-known bioactive metabolites, namely, the 1-series of prostaglandins (PGs1) and the 2-series of prostaglandins (PGs2), respectively. Unlike PGs2, which are generally viewed as proinflammatory and procarcinogenic PGs, PGs1 may possess anti-inflammatory and anti-cancer activity. Previous studies using ovine COX along with spin trapping and the LC/ESR/MS technique have shown that certain exclusive free radicals are generated from different free radical reactions in DGLA and AA peroxidation. However, it has been unclear whether the differences were associated with the contrasting bioactivity of DGLA vs AA. The aim of this study was to refine the LC/MS and spin trapping technique to make it possible for the association between free radicals and cancer cell growth to be directly tested. Using a colon cancer cell line, HCA-7 colony 29, and LC/MS along with a solid-phase extraction, we were able to characterize the reduced forms of radical adducts (hydroxylamines) as the free radicals generated from cellular COX-catalyzed peroxidation. For the first time, free radicals formed in the COX-catalyzed peroxidation of AA vs DGLA and their association with cancer cell growth were assessed (cell proliferation via MTS and cell cycle distribution via propidium iodide staining) in the same experimental setting. The exclusive free radicals formed from the COX-catalyzed peroxidation of AA and DGLA were shown to be correlated with the cell growth response. Our results indicate that free radicals generated from the distinct radical reactions in COX-catalyzed peroxidation may represent the novel metabolites of AA and DGLA that correspond to their contrasting bioactivity.

  16. Application of a newly developed hydrogen peroxide vapor phase sensor to HPV sterilizer.

    PubMed

    Taizo, I; Sinichi, A; Kawamura, K

    1998-01-01

    A new type of concentration sensor for hydrogen peroxide vapor has been developed by making use of a semiconductor. Output from the vapor sensor has been shown to have a good linear relationship with the logarithm of the concentration of hydrogen peroxide vapor. Concentration of hydrogen peroxide vapor introduced into the sterilization chamber could be kept constant by monitoring the concentration of the hydrogen peroxide vapor continuously and controlling the vapor supply. Temperature and humidity have also been kept constant. D-values for B. stearothermophilus ATCC 12980 at various concentrations of hydrogen peroxide vapor have been determined by using the combination system of the hydrogen peroxide vapor sensor, the hydrogen peroxide vapor supplier, thermosensor and humidity sensor. D-values at the temperature of 30 degrees C and the absolute humidity of 0.7 mg H2O/L thus obtained, were 0.2 minutes at hydrogen peroxide concentration of 600 ppm and 1.2 minutes at 200 ppm at the temperature of 30 degrees C and 0.7 mg/L absolute humidity. D-values for B. stearothermophilus ATCC 12980 at various temperatures, humidity and levels of hydrogen peroxide concentration have also been determined. These fundamental data indicate that the sterilization by hydrogen peroxide vapor can be validated as precisely as steam sterilization by measuring and controlling the concentration of hydrogen peroxide vapor using a combination of the hydrogen peroxide concentration sensor and the vapor generator. Influence of temperature and humidity have also been studied. The hydrogen peroxide sensor has been calibrated and standardized by using the standard hydrogen peroxide vapor whose concentration has been determined by calculating partial pressure of hydrogen peroxide over the water-hydrogen peroxide solution.

  17. Nanomolar hydrogen peroxide detection using horseradish peroxidase covalently linked to undoped nanocrystalline diamond surfaces.

    PubMed

    Wang, Qi; Kromka, Alexander; Houdkova, Jana; Babchenko, Oleg; Rezek, Bohuslav; Li, Musen; Boukherroub, Rabah; Szunerits, Sabine

    2012-01-10

    In this article, we report on the low-level detection of hydrogen peroxide, a key player in the redox signaling pathway and a toxic product in the cellular system, using a colorimetric solution assay. Amine-terminated undoped nanocrystalline diamond thin films were grown on glass using a linear-antenna microwave plasma CVD process. The diamond surface consists mainly of -NH(2) termination. The aminated diamond surface was decorated with horseradish peroxidase (HRP) enzyme using carbodiimide coupling chemistry. The success of the HRP immobilization was confirmed by X-ray photoelectron spectroscopy (XPS). The enzymatic activity of immobilized HRP was determined with a colorimetric test based on the HRP-catalyzed oxidation of 2,2'-azino-bis(3-ethylbenzothiazoline-6-sufonic acid (ABTS) in the presence of hydrogen peroxide. The surface coverage of active HRP was estimated to be Γ = 7.3 × 10(13) molecules cm(-2). The use of the functionalized diamond surface as an optical sensor for the detection of hydrogen peroxide with a detection limit of 35 nM was demonstrated.

  18. Biomimetic nitrogen doped titania nanoparticles as a colorimetric platform for hydrogen peroxide detection.

    PubMed

    Nasir, Muhammad; Rauf, Sajid; Muhammad, Nawshad; Hasnain Nawaz, Mian; Anwar Chaudhry, Aqif; Hamza Malik, Muhammad; Ahmad Shahid, Shakir; Hayat, Akhtar

    2017-11-01

    Nanoparticles proved a viable alternative to the already used sensing and diagnostics methods due to their low cost, good stability, easy availability and easy synthesis. In the present approach, nitrogen doped titania nanoparticles are prepared through freeze drying method, and subsequently stabilized through ionic liquid. These nanoparticles were characterized through various techniques such as X-ray diffraction (XRD), Fourier transformation infrared spectroscopy (FTIR), Scanning electron microscopy (SEM), BET pore size and surface area analyzer, X-ray photoelectron spectroscopy (XPS) and UV-Visible diffuse reflectance spectroscopy (UV-Vis. DRS). The synthesized nitrogen doped titania nanoparticles were proved to be a novel peroxidase mimetic with great potential to catalyze oxidation of 3,3',5,5'-tetramethylbenzidine (TMB) in the presence of hydrogen peroxide (H2O2) to form a blue color product. As a proof of concept, this new enzyme mimic was used as a robust nanoprobe for the detection of hydrogen peroxide with improved analytical characteristics. A linear response for hydrogen peroxide detection was obtained in the range of 10-300μmol/L, with a detection limit of 2.5μmol/L. Taking into account the valuable intrinsic peroxidase activity, the present work may find widespread applications in the field of sensors and biosensors for diverse applications. Copyright © 2017 Elsevier Inc. All rights reserved.

  19. Methionine oxidation by peroxymonocarbonate, a reactive oxygen species formed from CO2/bicarbonate and hydrogen peroxide.

    PubMed

    Richardson, David E; Regino, Celeste A S; Yao, Huirong; Johnson, Jodie V

    2003-12-15

    Kinetic and thermodynamic evidence is reported for the role of the peroxymonocarbonate ion, HCO4-, as a reactive oxygen species in biology. Peroxymonocarbonate results from the equilibrium reaction of hydrogen peroxide with bicarbonate via the perhydration of CO2. The kinetic parameters for HCO4- oxidation of free methionine have been obtained (k1 = 0.48 +/- 0.08 M(-1)s(-1) by a spectrophotometric initial rate method). At the physiological concentration of bicarbonate in blood ( approximately 25 mM), it is estimated that peroxymonocarbonate formed in equilibrium with hydrogen peroxide will oxidize methionine approximately 2-fold more rapidly than plasma H2O2 itself. As an example of methionine oxidation in proteins, the bicarbonate-catalyzed hydrogen peroxide oxidation of alpha1-proteinase inhibitor (alpha1-PI) has been investigated via its inhibitory effect on porcine pancreatic elastase activity. The second-order rate constant for HCO4- oxidation of alpha1-PI (0.36 +/- 0.06 M(-1)s(-1)) is comparable to that of free methionine, suggesting that methionine oxidation is occurring. Further evidence for methionine oxidation, specifically involving Met358 and Met351 of the alpha1-PI reactive center loop, has been obtained through amino acid analyses and mass spectroscopic analyses of proteolytic digests of the oxidized alpha1-PI. These results strongly suggest that HCO4- should be considered a reactive oxygen species in aerobic metabolism.

  20. A Spectrometric Method for Hydrogen Peroxide Concentration Measurement with a Reusable and Cost-Efficient Sensor

    PubMed Central

    Hsu, Cheng-Chih; Lo, Yuan-Rong; Lin, Yu-Chian; Shi, Yi-Cen; Li, Pang-Lung

    2015-01-01

    In this study we developed a low cost sensor for measuring the concentration of hydrogen peroxide (H2O2) in liquids utilizing a spectrometric method. The sensor was tested using various concentrations of a peroxidase enzyme immobilized on a glass substrate. H2O2 can be catalyzed by peroxidase and converted into water and oxygen. The reagent 4-amino-phenazone takes up oxygen together with phenol to form a colored product that has absorption peaks at 510 nm and 450 nm. The transmission intensity is strongly related to the hydrogen peroxide concentration, so can be used for quantitative analysis. The measurement range for hydrogen peroxide is from 5 × 10−5% to 1 × 10−3% (0.5 ppm to 10 ppm) and the results show high linearity. This device can achieve a sensitivity and resolution of 41,400 (photon count/%) and 3.49 × 10−5% (0.35 ppm), respectively. The response time of the sensor is less than 3 min and the sensor can be reused for 10 applications with similar performance. PMID:26473862

  1. Hydrogen Peroxide: A Key Chemical for Today's Sustainable Development.

    PubMed

    Ciriminna, Rosaria; Albanese, Lorenzo; Meneguzzo, Francesco; Pagliaro, Mario

    2016-12-20

    The global utilization of hydrogen peroxide, a green oxidant that decomposes in water and oxygen, has gone from 0.5 million tonnes per year three decades ago to 4.5 million tonnes per year in 2014, and is still climbing. With the aim of expanding the utilization of this eminent green chemical across different industrial and civil sectors, the production and use of hydrogen peroxide as a green industrial oxidant is reviewed herein to provide an overview of the explosive growth of its industrial use over the last three decades and of the state of the art in its industrial manufacture, with important details of what determines the viability of the direct production from oxygen and hydrogen compared with the traditional auto-oxidation process.

  2. Investigation on regeneration of basic hydrogen peroxide by electrochemical methods

    NASA Astrophysics Data System (ADS)

    Ke, Changchun; Chen, Wenwu; Xu, Xiaobo; Wang, Jinglong; Liu, Yushi; Jin, Yuqi; Sang, Fengting

    2015-02-01

    Two electrochemical methods for regeneration of Basic Hydrogen Peroxide (BHP) were investigated in this paper, which could be called one-step method and two-step method, respectively, distinguished by the number of steps during the regeneration process. The one-step method converts potassium chloride solution and oxygen directly to chlorine and BHP by a modified chlor-alkali cell with an oxygen cathode. For the one-step method, two reactors of different structure and corresponding regenerating process were designed. The experimental results showed that, for the continuous-type reactor, the highest peroxide concentration was 0.042 mol/L, while for batch-type reactor the highest peroxide concentration was 0.563 mol/L. The two-step method accomplishes the regeneration of BHP by a conventional chlor-alkali cell combined with a fuel cell reactor which could convert hydrogen and oxygen to peroxide in alkaline potassium hydroxide solution. A peroxide concentration of 2.450 mol/L was obtained for the two-step method.

  3. 40 CFR 180.1197 - Hydrogen peroxide; exemption from the requirement of a tolerance.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 23 2010-07-01 2010-07-01 false Hydrogen peroxide; exemption from the... Exemptions From Tolerances § 180.1197 Hydrogen peroxide; exemption from the requirement of a tolerance. An exemption from the requirement of a tolerance is established for residues of hydrogen peroxide in or on...

  4. 40 CFR 180.1197 - Hydrogen peroxide; exemption from the requirement of a tolerance.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 24 2011-07-01 2011-07-01 false Hydrogen peroxide; exemption from the... Exemptions From Tolerances § 180.1197 Hydrogen peroxide; exemption from the requirement of a tolerance. An exemption from the requirement of a tolerance is established for residues of hydrogen peroxide in or on...

  5. 40 CFR 415.90 - Applicability; description of the hydrogen peroxide production subcategory.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... hydrogen peroxide production subcategory. 415.90 Section 415.90 Protection of Environment ENVIRONMENTAL... SOURCE CATEGORY Hydrogen Peroxide Production Subcategory § 415.90 Applicability; description of the hydrogen peroxide production subcategory. The provisions of this subpart are applicable to...

  6. 21 CFR 172.167 - Silver nitrate and hydrogen peroxide solution.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 3 2011-04-01 2011-04-01 false Silver nitrate and hydrogen peroxide solution. 172... FOOD FOR HUMAN CONSUMPTION Food Preservatives § 172.167 Silver nitrate and hydrogen peroxide solution. An aqueous solution containing a mixture of silver nitrate and hydrogen peroxide may be safely...

  7. 21 CFR 172.167 - Silver nitrate and hydrogen peroxide solution.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Silver nitrate and hydrogen peroxide solution. 172... FOOD FOR HUMAN CONSUMPTION Food Preservatives § 172.167 Silver nitrate and hydrogen peroxide solution. An aqueous solution containing a mixture of silver nitrate and hydrogen peroxide may be safely...

  8. 40 CFR 415.90 - Applicability; description of the hydrogen peroxide production subcategory.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... hydrogen peroxide production subcategory. 415.90 Section 415.90 Protection of Environment ENVIRONMENTAL... SOURCE CATEGORY Hydrogen Peroxide Production Subcategory § 415.90 Applicability; description of the hydrogen peroxide production subcategory. The provisions of this subpart are applicable to...

  9. 40 CFR 180.1197 - Hydrogen peroxide; exemption from the requirement of a tolerance.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 25 2012-07-01 2012-07-01 false Hydrogen peroxide; exemption from the... Exemptions From Tolerances § 180.1197 Hydrogen peroxide; exemption from the requirement of a tolerance. An exemption from the requirement of a tolerance is established for residues of hydrogen peroxide in or on all...

  10. 40 CFR 415.90 - Applicability; description of the hydrogen peroxide production subcategory.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... hydrogen peroxide production subcategory. 415.90 Section 415.90 Protection of Environment ENVIRONMENTAL... SOURCE CATEGORY Hydrogen Peroxide Production Subcategory § 415.90 Applicability; description of the hydrogen peroxide production subcategory. The provisions of this subpart are applicable to discharges...

  11. 40 CFR 180.1197 - Hydrogen peroxide; exemption from the requirement of a tolerance.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 24 2014-07-01 2014-07-01 false Hydrogen peroxide; exemption from the... Exemptions From Tolerances § 180.1197 Hydrogen peroxide; exemption from the requirement of a tolerance. An exemption from the requirement of a tolerance is established for residues of hydrogen peroxide in or on all...

  12. 40 CFR 415.90 - Applicability; description of the hydrogen peroxide production subcategory.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... hydrogen peroxide production subcategory. 415.90 Section 415.90 Protection of Environment ENVIRONMENTAL... SOURCE CATEGORY Hydrogen Peroxide Production Subcategory § 415.90 Applicability; description of the hydrogen peroxide production subcategory. The provisions of this subpart are applicable to discharges...

  13. 40 CFR 415.90 - Applicability; description of the hydrogen peroxide production subcategory.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... hydrogen peroxide production subcategory. 415.90 Section 415.90 Protection of Environment ENVIRONMENTAL... SOURCE CATEGORY Hydrogen Peroxide Production Subcategory § 415.90 Applicability; description of the hydrogen peroxide production subcategory. The provisions of this subpart are applicable to discharges...

  14. 40 CFR 180.1197 - Hydrogen peroxide; exemption from the requirement of a tolerance.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 25 2013-07-01 2013-07-01 false Hydrogen peroxide; exemption from the... Exemptions From Tolerances § 180.1197 Hydrogen peroxide; exemption from the requirement of a tolerance. An exemption from the requirement of a tolerance is established for residues of hydrogen peroxide in or on all...

  15. Thermal Screening Of Residues From Acidification And Copper-Catalyzed Peroxide Oxidation Of Tank 48H Simulant

    SciTech Connect

    Fondeur, F. F.; Newell, J. D.; Peters, T. B.; Fink, S. D.

    2012-10-04

    This study evaluated the residues generated from copper-catalyzed peroxide oxidation (CCPO) of Tank 48H simulant. The first step of the CCPO calls for pH adjustment of the simulant, and early testing used either 15wt% or 50wt % nitric acid to reach a slurry pH of between 12 and 5. Residues obtained by ambient temperature pH adjustment with 50wt % nitric acid followed by oxidation with 50 wt % hydrogen peroxide at 35, 50, and 65°C (from a recently conducted Copper Catalyzed Peroxide Oxidation or CCPO) were also analyzed. Slurry samples at pH 7 or lower especially made from adding nitric acid at the process equivalent of one gallon per minute had the largest enthalpy of decomposition. The thermogravimetric characteristics of some samples from the CCPO test generated at pH 9 or lower exhibited rapid weight loss. Taken together, residues generated at pH 9 or lower may be classified as energetic upon decomposition in confined spaces or under adiabatic conditions. Therefore, additional testing is recommended with larger (up to 50mL) samples in an adiabatic calorimeter. To minimize risk of formation of energetic byproducts, an intermediate slurry pH of 9 or greater is recommended following the acidification step in the CCPO and prior to start of peroxide addition. In practice, process temperature needs to reach 150°C or greater to decompose residues obtained a pH 9 or lower which is unlikely. Oxidation temperature had no significant effect on the thermal characteristics of the final residues generated.

  16. Hydrogen peroxide modified sodium titanates with improved sorption capabilities

    DOEpatents

    Nyman, May D [Albuquerque, NM; Hobbs, David T [North Augusta, SC

    2009-02-24

    The sorption capabilities (e.g., kinetics, selectivity, capacity) of the baseline monosodium titanate (MST) sorbent material currently being used to sequester Sr-90 and alpha-emitting radioisotopes at the Savannah River Site are significantly improved when treated with hydrogen peroxide; either during the original synthesis of MST, or, as a post-treatment step after the MST has been synthesized. It is expected that these peroxide-modified MST sorbent materials will have significantly improved sorption capabilities for non-radioactive cations found in industrial processes and waste streams.

  17. Preparation of vermiculite nanoparticles using thermal hydrogen peroxide treatment.

    PubMed

    Weiss, Zdenĕk; Valásková, Marta; Seidlerová, Jana; Supová-Krístková, Monika; Sustai, Ondrej; Matĕjka, Vlastimil; Capková, Pavla

    2006-03-01

    Powdered natural Mg-vermiculite (Letovice, Czech Republic), with the formula (Mg0.35K0.02Ca0.01) (Mg2.39Fe0.51(3+)Fe0.02(2+)Al0.08) (Si2.64Al1.33Ti0.03) O10(OH)2 x 4.97H2O and particle size < 5 microm, was used for the investigation of exfoliation after hydrogen peroxide and/or microwave treatment (600 W). A sample heated in the microwave oven for 40 min exhibits a 11% mass loss and reduction of the 001 peak intensity in the X-ray diffraction pattern. The basal 001 peak intensity of untreated Mg-vermiculite sample (/001 = 100%) drops to 35% in the microwave treated sample. Only the sample treated for 5 h at 80 degrees C fully rehydrated after 120 min at room temperature. A more pronounced reduction of the 001 peak intensity (to 8%) was observed after hydrogen peroxide treatment of the sample at 25 degrees C. The combination of a five-hour hydrogen peroxide treatment at 80 degrees C and subsequent microwave heating leads to an effective extinction of the 001 diffraction in the XRD pattern. The 001 diffraction profile becomes very diffuse with peak intensity less than 1%. The degree of reduction of the 001 diffraction intensity also depends on the time and temperature of hydrogen peroxide treatment and on the peroxide concentration. An even more pronounced reduction of the peak intensity is caused by exfoliation of particles to nano-domains coupled with a randomization of the c-axes.

  18. Singlet oxygen in copper-catalyzed lipid peroxidation in erythrocyte membranes

    SciTech Connect

    Ding, A.H.; Chan, P.C.

    1984-04-01

    Lipid hydroperoxide was generated in human erythrocyte membranes by irradiation with near ultraviolet (UV) light in the presence of a photosensitizer, hematoporphyrin, but no production of 2-thiobarbituric acid-reactive materials (malonaldehyde and its precursors) was detected. Incubation of the irradiated membranes with CuSO4 led to increased levels of hydroperoxide and formation of malonaldehyde. Hydroperoxides were essential for initiating the Cu(II)-catalyzed peroxidation as no significant activity was observed with nonirradiated membranes and Cu(II) unless an organic peroxide, either t-butyl hydroperoxide or cumene hydroperoxide, was added. Catalytic activity was also found with Fe(II), but not with other metal ions tested. The peroxidation catalyzed with Cu(II) was partially inhibited by several singlet oxygen quenchers but was not affected by superoxide dismutase, catalase or OH radical scavengers. The possible involvement of singlet oxygen in the Cu(II)-catalyzed peroxidation reaction was further supported by a 3-fold enhancement of malonaldehyde production in D/sub 2/O.

  19. Continuous-flow synthesis of adipic acid from cyclohexene using hydrogen peroxide in high-temperature explosive regimes.

    PubMed

    Damm, Markus; Gutmann, Bernhard; Kappe, C Oliver

    2013-06-01

    Safe only in a microreactor! The synthesis of adipic acid from cyclohexene by tungstic acid-catalyzed oxidation using hydrogen peroxide following the classical Noyori protocol can be accomplished in good yields with residence times as short as 20 min at 140 °C using a safe and scalable microreactor environment. Under these intensified conditions the use of a phase-transfer catalyst is not required.

  20. Rational design of a lipase to accommodate catalysis of Baeyer-Villiger oxidation with hydrogen peroxide.

    PubMed

    Carlqvist, Peter; Eklund, Robert; Hult, Karl; Brinck, Tore

    2003-06-01

    The mechanism and potential energy surface for the Baeyer-Villiger oxidation of acetone with hydrogen peroxide catalyzed by a Ser105-Ala mutant of Candida antarctica Lipase B has been determined using ab initio and density functional theories. Initial substrate binding has been studied using an automated docking procedure and molecular dynamics simulations. Substrates were found to bind to the active site of the mutant. The activation energy for the first step of the reaction, the nucleophilic attack of hydrogen peroxide on the carbonyl carbon of hydrogen peroxide, was calculated to be 4.4 kcal x mol(-1) at the B3LYP/6-31+G* level. The second step, involving the migration of the alkyl group, was found to be the rate-determining step with a computed activation energy of 19.9 kcal x mol(-1) relative the reactant complex. Both steps were found to be lowered considerably in the reaction catalyzed by the mutated lipase, compared to the uncatalyzed reaction. The first step was lowered by 36.0 kcal x mol(-1) and the second step by 19.5 kcal x mol(-1). The second step of the reaction, the rearrangement step, has a high barrier of 27.7 kcal x mol(-1) relative to the Criegee intermediate. This could lead to an accumulation of the intermediate. It is not clear whether this result is an artifact of the computational procedure, or an indication that further mutations of the active site are required. Figure Second TS (18TS) in the Baeyer-Villiger oxidation in a mutant of CALB. Distances in A

  1. Effects of Martian Surface Materials on the Thermal Decomposition of Hydrogen Peroxide

    NASA Technical Reports Server (NTRS)

    Archer, P. D., Jr.

    2017-01-01

    While hydrogen peroxide (H2O2) has been detected in the martian atmosphere, it has not been detected in surface materials. Since the Viking lander mission, we have sent instruments to Mars with the capability to detect H2O2. The Sample Analysis at Mars (SAM) instrument onboard the Curiosity Rover and Thermal and Evolved Gas Analyzer (TEGA) instrument on the Phoenix lander both detected water and oxygen releases from analyzed sediments but whether or not peroxide could be the source of these gases has not been investigated. We are investigating the possible presence of H2O2 in martian materials by analyzing Mars-relevant minerals that have been mixed with hydrogen peroxide using lab instruments configured as analogs to Mars mission instruments. The object of this research is to use lab instruments to find the effects of Mars analog minerals on hydrogen peroxide gas release temperatures, specifically gas releases of water and oxygen and also determine the effect of the peroxide on the minerals. Data that we get from the lab can then be compared to the data collected from Mars. The minerals hematite, siderite, San Carlos olivine, magnetite and nontronite were chosen as our Mars analog minerals. 20 mg of analog Mars minerals with 5µl of 50% H2O2, and were either run immediately or placed in a sealed tube for 2, 4, or 9 days to look for changes over time with two reps being done at each time step to determine repeatability. Each sample was heated from -60 degC to 500 degC at 20 degC/min and the evolved gases were monitored with a mass spectrometer. Each sample was also analyzed with an X-ray diffraction instrument to look for changes in mineralogy. Preliminary results show three potential outcomes: 1) peroxide has no effect on the sample (e.g., hematite), 2) the mineral is unaffected but catalyzes peroxide decomposition (magnetite, siderite), or 3) peroxide alters the mineral (pyrrhotite, San Carlos olivine).

  2. The level of Hydrogen Peroxide in HeLa Cells in an Ozonated Medium.

    PubMed

    Kontorshchikova, K N; Belova, A S; Dudenkova, V V; Orlova, A G; Terent'ev, I G; Tsybusov, S N; Alyasova, A V

    2017-08-01

    We studied the role of hydrogen peroxide in the response of tumor cells to treatment with ozonated culture medium. Changes of the level of hydrogen peroxide in tumor cells incubated in ozonated medium were detected by using fluorescence microscopy and genetically-encoded sensor HyPer2. Modifications of fluorescent properties of the sensor reflecting accumulation of hydrogen peroxide in the cell cytoplasm were detected within 70 min from the start of exposure. The concentration of hydrogen peroxide continued to increase until 375 min. The revealed changes support the involvement of hydrogen peroxide in the cell response to ozone treatment.

  3. Heme degradation upon production of endogenous hydrogen peroxide via interaction of hemoglobin with sodium dodecyl sulfate.

    PubMed

    Salehi, N; Moosavi-Movahedi, A A; Fotouhi, L; Yousefinejad, S; Shourian, M; Hosseinzadeh, R; Sheibani, N; Habibi-Rezaei, M

    2014-04-05

    In this study the hemoglobin heme degradation upon interaction with sodium dodecyl sulfate (SDS) was investigated using UV-vis and fluorescence spectroscopy, multivariate curve resolution analysis, and chemiluminescence method. Our results showed that heme degradation occurred during interaction of hemoglobin with SDS producing three fluorescent components. We showed that the hydrogen peroxide, produced during this interaction, caused heme degradation. In addition, the endogenous hydrogen peroxide was more effective in hemoglobin heme degradation compared to exogenously added hydrogen peroxide. The endogenous form of hydrogen peroxide altered oxyHb to aquamethemoglobin and hemichrome at low concentration. In contrast, the exogenous hydrogen peroxide lacked this ability under same conditions.

  4. Hydrogen peroxide-induced apoptosis in human gingival fibroblasts.

    PubMed

    Gutiérrez-Venegas, Gloria; Guadarrama-Solís, Adriana; Muñoz-Seca, Carmen; Arreguín-Cano, Juan Antonio

    2015-01-01

    In the process of bleaching vital, discolored teeth, low concentrations of hydrogen peroxide (H2O2) are effective alternatives to heat-activated 30% H2O2. However, interest has been expressed in the assessment of pathological effects of long-term exposure to bleaching agents such as irritation and ulceration of the gingival or other soft tissues. The aim of the present study was to determine the effect of hydrogen peroxide on apoptosis in human gingival fibroblasts (HGF). Cytochrome c, Bcl-2, Bax, Bid and caspase-3 protein expression were detected by Western blotting. HGF cell apoptosis induced by H2O2 was both dose and time dependent. The addition of H2O2 resulted in the release of cytochrome c to the cytosol, and an increase of Caspase-3 cleavage. Data suggest that oxidative stress-induced apoptosis in HGF is intrinsic pathway involved the release of apoptotic signal from mitochondria.

  5. Glycerophosphate-dependent hydrogen peroxide production by rat liver mitochondria.

    PubMed

    Jesina, P; Kholová, D; Bolehovská, R; Cervinková, Z; Drahota, Z; Houstek, J

    2004-01-01

    We studied the extent to which hormonally-induced mitochondrial glycerophosphate dehydrogenase (mGPDH) activity contributes to the supply of reducing equivalents to the mitochondrial respiratory chain in the rat liver. The activity of glycerophosphate oxidase was compared with those of NADH oxidase and/or succinate oxidase. It was found that triiodothyronine-activated mGPDH represents almost the same capacity for the saturation of the respiratory chain as Complex II. Furthermore, the increase of mGPDH activity induced by triiodothyronine correlated with an increase of capacity for glycerophosphate-dependent hydrogen peroxide production. As a result of hormonal treatment, a 3-fold increase in glycerophosphate-dependent hydrogen peroxide production by liver mitochondria was detected by polarographic and luminometric measurements.

  6. Hydrogen peroxide bleaching of cotton in ultrasonic energy.

    PubMed

    Mistik, S Ilker; Yükseloglu, S Müge

    2005-12-01

    It is well known that, conventional hydrogen peroxide bleaching process is an important and a specific step for wet processors; however it has some problems such as long time, high energy consumption. On the other hand, using ultrasonic energy in bleaching is an alternative method for the conventional processes. In this work, 100% cotton materials of different forms such as raw fibre, ring-spun yarns and knitted fabrics produced from these cottons, were treated with hydrogen peroxide in two different concentrations (5 mL/L and 10 mL/L), at three different temperatures (20 degrees C, 30 degrees C, 40 degrees C) and times (20 min, 30 min, 60 min). Whiteness Index of the samples were then measured spectrophotometrically and the overall results were compared.

  7. Hydrogen peroxide-induced apoptosis in human gingival fibroblasts

    PubMed Central

    Gutiérrez-Venegas, Gloria; Guadarrama-Solís, Adriana; Muñoz-Seca, Carmen; Arreguín-Cano, Juan Antonio

    2015-01-01

    In the process of bleaching vital, discolored teeth, low concentrations of hydrogen peroxide (H2O2) are effective alternatives to heat-activated 30% H2O2. However, interest has been expressed in the assessment of pathological effects of long-term exposure to bleaching agents such as irritation and ulceration of the gingival or other soft tissues. The aim of the present study was to determine the effect of hydrogen peroxide on apoptosis in human gingival fibroblasts (HGF). Cytochrome c, Bcl-2, Bax, Bid and caspase-3 protein expression were detected by Western blotting. HGF cell apoptosis induced by H2O2 was both dose and time dependent. The addition of H2O2 resulted in the release of cytochrome c to the cytosol, and an increase of Caspase-3 cleavage. Data suggest that oxidative stress-induced apoptosis in HGF is intrinsic pathway involved the release of apoptotic signal from mitochondria. PMID:26884825

  8. Ultraviolet absorption spectrum of hydrogen peroxide vapor. [for atmospheric abundances

    NASA Technical Reports Server (NTRS)

    Molina, L. T.; Schinke, S. D.; Molina, M. J.

    1977-01-01

    The ultraviolet absorption cross sections of hydrogen peroxide vapor have been determined over the wavelength range 210 to 350 nm at 296 K. At the longer wavelengths, the gas phase absorptivities are significantly larger than the corresponding values in condensed phase. The atmospheric H2O2 photodissociation rate for overhead sun at the earth's surface is estimated to be about 1.3 x 10 to the -5th/sec.

  9. SONEX-Hydrogen Peroxide, Methylhydroperoxide and Formaldehyde Measurements

    NASA Technical Reports Server (NTRS)

    Heikes, Brian

    1999-01-01

    We measured gas phase H2O2, CH3OOH, and CH2O on board the NASA DC-8 during the SONEX field mission, presented preliminary results at three scientific meetings, participated in two data workshops and contributed to joint publications of final results. The observations of peroxides and formaldehyde were instrumental in assessing odd-hydrogen radical chemistry, ozone chemistry, and in tracing meteorological transport paths.

  10. Novel aqueous dual-channel aluminum-hydrogen peroxide battery

    NASA Astrophysics Data System (ADS)

    Marsh, Catherine; Licht, Stuart

    1994-06-01

    A dual-channel aluminum hydrogen peroxide battery is introduced with an open-circuit voltage of 1.9 volts, polarization losses of 0.9 mV cm(exp 2) mA(exp -1), and power densities of 1 W/cm(exp 2). Catholyte and anolyte cell compartments are separated by an Ir/Pd modified porous nickel cathode. Separation of catholyte and anolyte chambers prevents hydrogen peroxide poisoning of the aluminum anode. The battery is expressed by aluminum oxidation and aqueous solution phase hydrogen peroxide reduction for an overall battery discharge consisting of 2Al + 3H2O2 + 2OH(-) yields 2AlO2(-) + 4H2O E = 2.3 V. The search for electrical propulsion sources which fit the requirements for electrically powered vehicles has blurred the standard characteristics associated with electrochemical storage systems. Presently, electrochemical systems comprised of mechanically rechargeable primary batteries, secondary batteries, and fuel cells are candidates for electrochemical propulsion sources. While important advances in energy and power density continue for nonaqueous and molten electrolytes, aqueous electrolyte batteries often have an advantage in simplicity, conductivity, cost effectiveness, and environmental impact. Systems coupling aluminum anodes and aqueous electrolytes have been investigated. These systems include: aluminum/silver oxide, aluminum/manganese dioxide, aluminum air, aluminum/hydrogen peroxide aqueous batteries, and the recently introduced aluminum/ferricyanide and aluminum sulfur aqueous batteries. Conventional aqueous systems such as the nickel cadmium and lead-acid batteries are characterized by their relatively low energy densities and adverse environmental impact. Other systems have substantially higher theoretical energy capacities. While aluminum-silver oxide has demonstrated the highest steady-state power density, its high cost is an impediment for widespread utilization for electric propulsion.

  11. Inactivation of porcine kidney betaine aldehyde dehydrogenase by hydrogen peroxide.

    PubMed

    Rosas-Rodríguez, Jesús A; Valenzuela-Soto, Elisa M

    2011-05-30

    Concentrated urine formation in the kidney is accompanied by conditions that favor the accumulation of reactive oxygen species (ROS). Under hyperosmotic conditions, medulla cells accumulate glycine betaine, which is an osmolyte synthesized by betaine aldehyde dehydrogenase (BADH, EC 1.2.1.8). All BADHs identified to date have a highly reactive cysteine residue at the active site, and this cysteine is susceptible to oxidation by hydrogen peroxide. Porcine kidney BADH incubated with H(2)O(2) (0-500 μM) lost 25% of its activity. However, pkBADH inactivation by hydrogen peroxide was limited, even after 120 min of incubation. The presence of coenzyme NAD(+) (10-50 μM) increased the extent of inactivation (60%) at 120 min of reaction, but the ligands betaine aldehyde (50 and 500 μM) and glycine betaine (100 mM) did not change the rate or extent of inactivation as compared to the reaction without ligand. 2-Mercaptoethanol and dithiothreitol, but not reduced glutathione, were able to restore enzyme activity. Mass spectrometry analysis of hydrogen peroxide inactivated BADH revealed oxidation of M278, M243, M241 and H335 in the absence and oxidation of M94, M327 and M278 in the presence of NAD(+). Molecular modeling of BADH revealed that the oxidized methionine and histidine residues are near the NAD(+) binding site. In the presence of the coenzyme, these oxidized residues are proximal to the betaine aldehyde binding site. None of the oxidized amino acid residues participates directly in catalysis. We suggest that pkBADH inactivation by hydrogen peroxide occurs via disulfide bond formation between vicinal catalytic cysteines (C288 and C289). Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.

  12. Hydrogen peroxide propulsion for smaller satellites (SSC98-VIII-1)

    SciTech Connect

    Whitehead, J C

    1998-07-13

    As satellite designs shrink, providing maneuvering and control capability falls outside the realm of available propulsion technology. While cold gas has been used on the smallest satellites, hydrogen peroxide propellant is suggested as the next step in performance and cost before hydrazine. Minimal toxicity and a small scale enable benchtop propellant preparation and development testing. Progress toward low-cost thrusters and self-pressurizing tank systems is described.

  13. Direct synthesis of hydrogen peroxide in water at ambient temperature.

    PubMed

    Crole, David A; Freakley, Simon J; Edwards, Jennifer K; Hutchings, Graham J

    2016-06-01

    The direct synthesis of hydrogen peroxide (H2O2) from hydrogen and oxygen has been studied using an Au-Pd/TiO2 catalyst. The aim of this study is to understand the balance of synthesis and sequential degradation reactions using an aqueous, stabilizer-free solvent at ambient temperature. The effects of the reaction conditions on the productivity of H2O2 formation and the undesirable hydrogenation and decomposition reactions are investigated. Reaction temperature, solvent composition and reaction time have been studied and indicate that when using water as the solvent the H2O2 decomposition reaction is the predominant degradation pathway, which provides new challenges for catalyst design, which has previously focused on minimizing the subsequent hydrogenation reaction. This is of importance for the application of this catalytic approach for water purification.

  14. Pseudomonas aeruginosa Thiol Peroxidase Protects against Hydrogen Peroxide Toxicity and Displays Atypical Patterns of Gene Regulation

    PubMed Central

    Somprasong, Nawarat; Jittawuttipoka, Thichakorn; Duang-nkern, Jintana; Romsang, Adisak; Chaiyen, Pimchai; Schweizer, Herbert P.; Vattanaviboon, Paiboon

    2012-01-01

    The Pseudomonas aeruginosa PAO1 thiol peroxidase homolog (Tpx) belongs to a family of enzymes implicated in the removal of toxic peroxides. We have shown the expression of tpx to be highly inducible with redox cycling/superoxide generators and diamide and weakly inducible with organic hydroperoxides and hydrogen peroxide (H2O2). The PAO1 tpx pattern is unlike the patterns for other peroxide-scavenging genes in P. aeruginosa. Analysis of the tpx promoter reveals the presence of a putative IscR binding site located near the promoter. The tpx expression profiles in PAO1 and the iscR mutant, together with results from gel mobility shift assays showing that purified IscR specifically binds the tpx promoter, support the role of IscR as a transcriptional repressor of tpx that also regulates the oxidant-inducible expression of the gene. Recombinant Tpx has been purified and biochemically characterized. The enzyme catalyzes thioredoxin-dependent peroxidation and can utilize organic hydroperoxides and H2O2 as substrates. The Δtpx mutant demonstrates differential sensitivity to H2O2 only at moderate concentrations (0.5 mM) and not at high (20 mM) concentrations, suggesting a novel protective role of tpx against H2O2 in P. aeruginosa. Altogether, P. aeruginosa tpx is a novel member of the IscR regulon and plays a primary role in protecting the bacteria from submillimolar concentrations of H2O2. PMID:22609922

  15. Pseudomonas aeruginosa thiol peroxidase protects against hydrogen peroxide toxicity and displays atypical patterns of gene regulation.

    PubMed

    Somprasong, Nawarat; Jittawuttipoka, Thichakorn; Duang-Nkern, Jintana; Romsang, Adisak; Chaiyen, Pimchai; Schweizer, Herbert P; Vattanaviboon, Paiboon; Mongkolsuk, Skorn

    2012-08-01

    The Pseudomonas aeruginosa PAO1 thiol peroxidase homolog (Tpx) belongs to a family of enzymes implicated in the removal of toxic peroxides. We have shown the expression of tpx to be highly inducible with redox cycling/superoxide generators and diamide and weakly inducible with organic hydroperoxides and hydrogen peroxide (H(2)O(2)). The PAO1 tpx pattern is unlike the patterns for other peroxide-scavenging genes in P. aeruginosa. Analysis of the tpx promoter reveals the presence of a putative IscR binding site located near the promoter. The tpx expression profiles in PAO1 and the iscR mutant, together with results from gel mobility shift assays showing that purified IscR specifically binds the tpx promoter, support the role of IscR as a transcriptional repressor of tpx that also regulates the oxidant-inducible expression of the gene. Recombinant Tpx has been purified and biochemically characterized. The enzyme catalyzes thioredoxin-dependent peroxidation and can utilize organic hydroperoxides and H(2)O(2) as substrates. The Δtpx mutant demonstrates differential sensitivity to H(2)O(2) only at moderate concentrations (0.5 mM) and not at high (20 mM) concentrations, suggesting a novel protective role of tpx against H(2)O(2) in P. aeruginosa. Altogether, P. aeruginosa tpx is a novel member of the IscR regulon and plays a primary role in protecting the bacteria from submillimolar concentrations of H(2)O(2).

  16. Luminol-hydrogen peroxide chemiluminescence produced by sweet potato peroxidase.

    PubMed

    Alpeeva, Inna S; Yu Sakharov, Ivan

    2007-01-01

    Anionic sweet potato peroxidase (SPP; Ipomoea batatas) was shown to efficiently catalyse luminol oxidation by hydrogen peroxide, forming a long-term chemiluminescence (CL) signal. Like other anionic plant peroxidases, SPP is able to catalyse this enzymatic reaction efficiently in the absence of any enhancer. Maximum intensity produced in SPP-catalysed oxidation of luminol was detected at pH 7.8-7.9 to be lower than that characteristic of other peroxidases (8.4-8.6). Varying the concentrations of luminol, hydrogen peroxide and Tris buffer in the reaction medium, we determined favourable conditions for SPP catalysis (100 mmol/L Tris-HCl buffer, pH 7.8, containing 5 mmol/L hydrogen peroxide and 8 mmol/L luminol). The SPP detection limit in luminol oxidation was 1.0 x 10(-14) mol/L. High sensitivity in combination with the long-term CL signal and high stability is indicative of good promise for the application of SPP in CL enzyme immunoassay.

  17. Treatment of ammonia contaminated water by ozone and hydrogen peroxide

    SciTech Connect

    Yuan, F.; Hill, D.O.; Kuo, C.H.

    1995-12-31

    The present research concerns kinetics of oxidation of ammonia by ozone and ozone-hydrogen peroxide mixtures in alkaline solutions. Experiments were carried out at 15 to 35{degrees}C in solutions with pH values varying from 8 to 10 utilizing a stopped-flow spectrophotometer system. Fractions of free ammonia present in acidic and neutral solutions are negligible, and the reaction is very slow. This confirms that only free ammonia can react with ozone in the aqueous phase. The reaction proceeds at moderate rates in the alkaline solutions requiring four moles of ozone to react with each mole of ammonia. The free ammonia is oxidized and converted completely to nitrate in the solutions. The overall reaction between ammonia and ozone is second order with first order in each reactant. The reaction rate constant increases with temperature and pH value of the solution. The average activation energy is 59 Kcal/gmol for all systems investigated at different pH values. The results of the kinetic experiments suggest that the reaction is predominated by the direct oxidation between ammonia and ozone molecules, and that the hydroxyl radical reactions play insignificant roles in the ozonation process. The oxidation rate of ammonia is enhanced considerably in the presence of hydrogen peroxide and ozone mixtures. The formation of hydroxyl radical from interactions between ozone and hydrogen peroxide and the subsequent free radical reactions of ammonia seem important in controlling the destruction rate of free ammonia, as suggested by the results of this study.

  18. A reaction-diffusion model of cytosolic hydrogen peroxide.

    PubMed

    Lim, Joseph B; Langford, Troy F; Huang, Beijing K; Deen, William M; Sikes, Hadley D

    2016-01-01

    As a signaling molecule in mammalian cells, hydrogen peroxide (H2O2) determines the thiol/disulfide oxidation state of several key proteins in the cytosol. Localization is a key concept in redox signaling; the concentrations of signaling molecules within the cell are expected to vary in time and in space in manner that is essential for function. However, as a simplification, all theoretical studies of intracellular hydrogen peroxide and many experimental studies to date have treated the cytosol as a well-mixed compartment. In this work, we incorporate our previously reported reduced kinetic model of the network of reactions that metabolize hydrogen peroxide in the cytosol into a model that explicitly treats diffusion along with reaction. We modeled a bolus addition experiment, solved the model analytically, and used the resulting equations to quantify the spatiotemporal variations in intracellular H2O2 that result from this kind of perturbation to the extracellular H2O2 concentration. We predict that micromolar bolus additions of H2O2 to suspensions of HeLa cells (0.8 × 10(9)cells/l) result in increases in the intracellular concentration that are localized near the membrane. These findings challenge the assumption that intracellular concentrations of H2O2 are increased uniformly throughout the cell during bolus addition experiments and provide a theoretical basis for differing phenotypic responses of cells to intracellular versus extracellular perturbations to H2O2 levels. Copyright © 2015 Elsevier Inc. All rights reserved.

  19. Quantification of peroxide ion passage in dentin, enamel, and cementum after internal bleaching with hydrogen peroxide.

    PubMed

    Palo, R M; Bonetti-Filho, I; Valera, M C; Camargo, C H R; Camargo, Sea; Moura-Netto, C; Pameijer, C

    2012-01-01

    The aim of this study was to evaluate the amount of peroxide passage from the pulp chamber to the external enamel surface during the internal bleaching technique. Fifty bovine teeth were sectioned transversally 5 mm below the cemento-enamel junction (CEJ), and the remaining part of the root was sealed with a 2-mm layer of glass ionomer cement. The external surface of the samples was coated with nail varnish, with the exception of standardized circular areas (6-mm diameter) located on the enamel, exposed dentin, or cementum surface of the tooth. The teeth were divided into three experimental groups according to exposed areas close to the CEJ and into two control groups (n=10/group), as follows: GE, enamel exposure area; GC, cementum exposed area; GD, dentin exposed area; Negative control, no presence of internal bleaching agent and uncoated surface; and Positive control, pulp chamber filled with bleaching agent and external surface totally coated with nail varnish. The pulp chamber was filled with 35% hydrogen peroxide (Opalescence Endo, Ultradent). Each sample was placed inside of individual flasks with 1000 μL of acetate buffer solution, 2 M (pH 4.5). After seven days, the buffer solution was transferred to a glass tube, in which 100 μL of leuco-crystal violet and 50 μL of horseradish peroxidase were added, producing a blue solution. The optical density of the blue solution was determined by spectrophotometer and converted into microgram equivalents of hydrogen peroxide. Data were submitted to Kruskal-Wallis and Dunn-Bonferroni tests (α=0.05). All experimental groups presented passage of peroxide to the external surface that was statistically different from that observed in the control groups. It was verified that the passage of peroxide was higher in GD than in GE (p<0.01). The GC group presented a significantly lower peroxide passage than did GD and GE (p<0.01). It can be concluded that the hydrogen peroxide placed into the pulp chamber passed through the

  20. Iridium-Catalyzed Asymmetric Hydrogenation of Unsaturated Carboxylic Acids.

    PubMed

    Zhu, Shou-Fei; Zhou, Qi-Lin

    2017-04-04

    Chiral carboxylic acid moieties are widely found in pharmaceuticals, agrochemicals, flavors, fragrances, and health supplements. Although they can be synthesized straightforwardly by transition-metal-catalyzed enantioselective hydrogenation of unsaturated carboxylic acids, because the existing chiral catalysts have various disadvantages, the development of new chiral catalysts with high activity and enantioselectivity is an important, long-standing challenge. Ruthenium complexes with chiral diphosphine ligands and rhodium complexes with chiral monodentate or bidentate phosphorus ligands have been the predominant catalysts for asymmetric hydrogenation of unsaturated acids. However, the efficiency of these catalysts is highly substrate-dependent, and most of the reported catalysts require a high loading, high hydrogen pressure, or long reaction time for satisfactory results. Our recent studies have revealed that chiral iridium complexes with chiral spiro-phosphine-oxazoline ligands and chiral spiro-phosphine-benzylamine ligands exhibit excellent activity and enantioselectivity in the hydrogenation of α,β-unsaturated carboxylic acids, including α,β-disubstituted acrylic acids, trisubstituted acrylic acids, α-substituted acrylic acids, and heterocyclic α,β-unsaturated acids. On the basis of an understanding of the role of the carboxy group in iridium-catalyzed asymmetric hydrogenation reactions, we developed a carboxy-group-directed strategy for asymmetric hydrogenation of olefins. Using this strategy, we hydrogenated several challenging olefin substrates, such as β,γ-unsaturated carboxylic acids, 1,1-diarylethenes, 1,1-dialkylethenes, and 1-alkyl styrenes in high yield and with excellent enantioselectivity. All these iridium-catalyzed asymmetric hydrogenation reactions feature high turnover numbers (up to 10000) and turnover frequencies (up to 6000 h(-1)), excellent enantioselectivities (greater than 95% ee with few exceptions), low hydrogen pressure (<12 atm

  1. Direct reduction of hydrogen peroxides into hydroxyl ions in peroxide-based fuel cell

    NASA Astrophysics Data System (ADS)

    Luo, Nie; Miley, George H.; Noid, D. W.

    2004-03-01

    We study the catalytic electrochemical reduction of hydrogen peroxide (H_2O2 + 2 e = 2 OH^-) at the electrolyte/cathode interface of peroxide fuel cells. This is the desired reaction for high efficiency fuel cell operation, but is nevertheless in competition with wasteful processes such as the direct decomposition of H_2O2 to water and oxygen gas. The reaction kinetics of these competing processes is calculated with thermodynamic and electrochemical data of relevant materials, resulting in a qualitative guide on the selection of effective catalyst and cathode compositions. The experimental research includes cyclic voltammetry, used to probe the surface electrochemistry of the catalytic process, and shed light on how proper theories are restricted experimentally. The fuel cell based on direct hydrogen peroxide cathode has the following distinct advantages: i) Very high volumetric power density (several times higher than ordinary H_2O2 fuel cells) through direct utilization of a liquid phase oxidant at the cathode; (ii) The potential for high efficiency (over 60%): use of H_2O2 eliminates the oxygen over-potential problem inherent to ordinary H_2O2 fuel cell designs, which require transfer of four electrons simultaneously; (iii) Safe, and stable storage of the energetic materials.

  2. [Ingestion of hydrogen peroxide. Apropos of 3 cases].

    PubMed

    Brea Hernando, A J; Martín Burcio, S

    1991-03-02

    Hydrogen peroxide is used as a preserver in milk industry. Three cases of accidental ingestion of 60% hydrogen peroxide (oxygenated water 200 volumes). The patients were male stockbreeders aged 30, 45 and 62 years, respectively, who stored that powerful oxidizing agent in commercial drink containers without adequate labeling. One of them was admitted comatose and required assisted ventilation. After recovering consciousness migratory paresis of right limbs and of the VI cranial nerve were observed, which were reversed after ten days, and left hemiparesia that persisted for two months. Upper gastrointestinal tract lesions, particularly in stomach, were detected in all. The endoscopic and pathological findings are described in detail. The outcome was satisfactory in the three patients, with complete remission of the lesions. There appears to be a direct relationship between the severity of symptoms and the amount of ingested peroxide, dependent on the diameter of the opening of the container. Only five reports have been identified related to the oral poisoning by this substance.

  3. Durability of bleaching results achieved with 15% carbamide peroxide and 38% hydrogen peroxide in vitro.

    PubMed

    Knösel, Michael; Reus, Monika; Rosenberger, Albert; Attin, Thomas; Ziebolz, Dirk

    2011-01-01

    The aim of this study was to assess the durability of bleaching results achieved with (1) 15% carbamide peroxide home bleaching and (2) 38% hydrogen peroxide in-office bleaching. A total of 231 extracted anterior teeth were randomly divided into three groups (n = 77 in each group) with comparable mean baseline L*-values (68.24 ± 0.8): a non-bleached control group A, a 15% carbamide peroxide group B (5 bleaching intervals of 8 hours), and a 38% hydrogen peroxide group C (3 intervals of 15 minutes). Durability of bleaching was assessed by comparing CIE-L*a*b* data after intervals of 2, 4, 12, and 26 weeks from baseline. Both bleaching regimes initially produced a highly significant increase in lightness parameter L*, with no significant difference between the respective bleaching regimes (B: 68.23 / 72.48; C: 68.32 / 73.25). Six months after starting the trial, L*-values for group B yielded no significant differences compared to baseline (69.55), whereas L*-values for group C were still significantly raised (69.91), despite a highly significant decrease when compared to initial bleaching results. In both treatment groups, there was a lasting response to bleaching in terms of CIE-a* and -b* value decreases. Results for both home- and in-practice regimes were found to be similar for about 12 weeks. However, in-office results were longer lasting, despite the shorter treatment intervals. Summarized bleaching effects, in terms of delta E values, revealed no significant differences between treatment groups and the control group after 6 months, indicating an abatement of the bleaching results achieved.

  4. Hydrogenation of liquid natural rubber via diimide reduction in hydrazine hydrate/hydrogen peroxide system

    SciTech Connect

    Yusof, Muhammad Jefri Mohd; Jamaluddin, Naharullah; Abdullah, Ibrahim; Yusoff, Siti Fairus M.

    2015-09-25

    Liquid natural rubber (LNR) with molecular weight of lower than 10{sup 5} and shorter polymeric chain than natural rubber was prepared. LNR was then hydrogenated via diimide reduction by oxidation of hydrazine hydrate with hydrogen peroxide. The unsaturated units of the rubber were converted into saturated hydrocarbon to strengthen the backbone of the polymer so it was able to resist thermal degradation. The results indicated that hydrogenation degree of the product (HLNR) could be extended to 91.2% conversion under appropriate conditions. The hydrogenated LNR (HLNR) was characterized using Fourier-Transform Infrared (FTIR) and Nuclear Magnetic Resonance (NMR) spectroscopy. The physical characteristics of HLNR were analyzed with Termogravimetric Analysis (TGA)

  5. Photochemical formation of hydrogen peroxide in surface and ground waters exposed to sunlight

    SciTech Connect

    Cooper, W.J.; Zika, R.G.

    1983-05-13

    A rapid increase in the concentration of hydrogen peroxide was observed when samples of natural surface and ground water from various locations in the United States were exposed to sunlight. The hydrogen peroxide is photochemically generated from organic constitutents present in the water; humic materials are believed to be the primary agent producing the peroxide. Studies with superoxide dismutase suggest that the superoxide anion is the precursor of the peroxide.

  6. Uptake of isoprene, methacrylic acid and methyl methacrylate into aqueous solutions of sulfuric acid and hydrogen peroxide.

    PubMed

    Liu, Ze; Ge, Maofa; Wang, Weigang

    2012-01-01

    Multiphase acid-catalyzed oxidation by hydrogen peroxide has been suggested to be a potential route to secondary organic aerosol formation from isoprene and its gas-phase oxidation products, but the lack of kinetics data significantly limited the evaluation of this process in the atmosphere. Here we report the first measurement of the uptake of isoprene, methacrylic acid and methyl methacrylate into aqueous solutions of sulfuric acid and hydrogen peroxide. Isoprene cannot readily partition into the solution because of its high volatility and low solubility, which hinders its further liquid-phase oxidation. Both methacrylic acid and methyl methacrylate can enter the solutions and be oxidized by hydrogen peroxide, and steady-state uptake was observed with the acidity of solution above 30 wt.% and 70 wt.%, respectively. The steady-state uptake coefficient of methacrylic acid is much larger than that of methyl methacrylate for a solution with same acidity. These observations can be explained by the different reactivity of these two compounds caused by the different electron-withdrawing conjugation between carboxyl and ester groups. The atmospheric lifetimes were estimated based on the calculated steady-state uptake coefficients. These results demonstrate that the multiphase acid-catalyzed oxidation of methacrylic acid plays a role in secondary organic aerosol formation, but for isoprene and methyl methacrylate, this process is not important in the troposphere.

  7. Efficacy of hydrogen peroxide for treating saprolegniasis in channel catfish

    USGS Publications Warehouse

    Howe, G.E.; Gingerich, W.H.; Dawson, V.K.; Olson, J.J.

    1999-01-01

    Hatchery-reared fish and their eggs are commonly afflicted with saprolegniasis, a fungal disease that can cause significant losses in production. Fish culturists need safe and effective fungicides to minimize losses and meet production demands. The efficacy of hydrogen peroxide was evaluated for preventing or controlling mortality associated with saprolegniasis in channel catfish Ictalurus punctatus. Saprolegniasis was systematically induced in channel catfish so various therapies could be evaluated in a controlled laboratory environment. Both prophylactic and therapeutic hydrogen peroxide bath treatments of 50, 100, and 150 ??L/L for 1 h were administered every other day for seven total treatments. All untreated positive control fish died of saprolegniasis during the prophylactic and therapeutic tests. Hydrogen peroxide treatments of 150 ??L/L were harmful (relative to lower concentrations) to test fish and resulted in 73-95% mortality. Mortality was attributed to a combination of abrasion, temperature, chemical treatment, and disease stressors. Treatments of 100 ??L/L were less harmful (relatively) but also appeared to contribute to mortality (60-79%). These treatments, however, significantly reduced the incidence of mortality and infection compared with those observed for fish of the positive control or 150-??L/L treatment groups. Overall, treatments of 50 ??L/L were found to be the most safe and effective of those tested. Mortality with this concentration ranged from 16% in therapeutic tests to 41% in prophylactic tests. The statistical model employed estimated that the optimum treatment concentration for preventing or controlling mortality, reducing the incidence of infections, and enhancing the recovery of infected fish was 75 ??L H2O2/L.

  8. Vapor hydrogen peroxide as alternative to dry heat microbial reduction

    NASA Astrophysics Data System (ADS)

    Chung, S.; Kern, R.; Koukol, R.; Barengoltz, J.; Cash, H.

    2008-09-01

    The Jet Propulsion Laboratory (JPL), in conjunction with the NASA Planetary Protection Officer, has selected vapor phase hydrogen peroxide (VHP) sterilization process for continued development as a NASA approved sterilization technique for spacecraft subsystems and systems. The goal was to include this technique, with an appropriate specification, in NASA Procedural Requirements 8020.12 as a low-temperature complementary technique to the dry heat sterilization process. The VHP process is widely used by the medical industry to sterilize surgical instruments and biomedical devices, but high doses of VHP may degrade the performance of flight hardware, or compromise material compatibility. The goal for this study was to determine the minimum VHP process conditions for planetary protection acceptable microbial reduction levels. Experiments were conducted by the STERIS Corporation, under contract to JPL, to evaluate the effectiveness of vapor hydrogen peroxide for the inactivation of the standard spore challenge, Geobacillus stearothermophilus. VHP process parameters were determined that provide significant reductions in spore viability while allowing survival of sufficient spores for statistically significant enumeration. In addition to the obvious process parameters of interest: hydrogen peroxide concentration, number of injection cycles, and exposure duration, the investigation also considered the possible effect on lethality of environmental parameters: temperature, absolute humidity, and material substrate. This study delineated a range of test sterilizer process conditions: VHP concentration, process duration, a process temperature range for which the worst case D-value may be imposed, a process humidity range for which the worst case D-value may be imposed, and the dependence on selected spacecraft material substrates. The derivation of D-values from the lethality data permitted conservative planetary protection recommendations.

  9. Peroxide decoloration of CI Acid Orange 7 catalyzed by manganese chlorophyll derivatives at the surfaces of micelles and lipid bilayers.

    PubMed

    Ishigure, Shuichi; Mitsui, Tatsuro; Ito, Shingo; Kondo, Yuji; Kawabe, Shigeki; Kondo, Masaharu; Dewa, Takehisa; Mino, Hiroyuki; Itoh, Shigeru; Nango, Mamoru

    2010-06-01

    Manganese-substituted chlorophyll a derivatives (MnChls) were synthesized. We first report peroxidative oxidation of an azo dye, CI Acid Orange 7, catalyzed by MnChls at the surfaces of micelles and lipid bilayers with hydrogen peroxide (H(2)O(2)) under mild conditions (pH 8.0, 25 degrees C). Peroxide decoloration depended upon the structures of MnChls, surfactants, lipids, and the presence of imidazole. Surprisingly, a largest decoloration rate was observed for MnChls dimer, MnPChlide a-K(MnPChlide a)-His 5 in cetyltrimethylammonium bromide (CTAB) micellar solution, especially when imidazole was present: this observation is analogous to the decoloration using horseradish peroxidase (HRP). Interestingly, the dimer complexes showed enhanced decoloration in comparison to the corresponding MnChls monomer in the micellar solution. In contrast, the MnChls monomer showed enhanced decoloration in comparison with the MnChls dimer in liposomal suspensions. Further, the imidazole residue covalently linked to the MnChls plays an important role in increasing the decoloration in both micellar and liposomal suspensions as well as in addition of imidazole into the solutions. It is interesting that the electron paramagnetic resonance (EPR) spectra of MnPChlide a ME 2, MnPChlide a-His 3, and MnMPMME-His 7 have 16 peaks around g = 2 in Egg PC or DMPC liposomal suspension with H(2)O(2), which is typical of a mixed-valence Mn(III)-Mn(IV) complex with coupling between two ions. The higher decoloration performance obtained by the monomer porphyrin compounds at the surface of the lipid bilayers appears to be related to the stability of this mixed-valence Mn(III)-Mn(IV) species formed in the lipid bilayers. This finding should provide useful information to note that MnChls, which are easily found in a number of biological systems, are involved in functions such as hydrogen peroxide decomposition in bacteria and the oxidation of water during photosynthesis as well as the peroxidases

  10. Apparatus and method for treating pollutants in a gas using hydrogen peroxide and UV light

    NASA Technical Reports Server (NTRS)

    Cooper, Charles David (Inventor); Clausen, Christian Anthony (Inventor)

    2005-01-01

    An apparatus for treating pollutants in a gas may include a source of hydrogen peroxide, and a treatment injector for creating and injecting dissociated hydrogen peroxide into the flow of gas. The treatment injector may further include an injector housing having an inlet, an outlet, and a hollow interior extending therebetween. The inlet may be connected in fluid communication with the source of hydrogen peroxide so that hydrogen peroxide flows through the hollow interior and toward the outlet. At least one ultraviolet (UV) lamp may be positioned within the hollow interior of the injector housing. The at least one UV lamp may dissociate the hydrogen peroxide flowing through the tube. The dissociated hydrogen peroxide may be injected into the flow of gas from the outlet for treating pollutants, such as nitrogen oxides.

  11. APPARATUS AND METHOD FOR TREATING POLLUTANTS IN A GAS USING HYDROGEN PEROXIDE AND UV LIGHT

    NASA Technical Reports Server (NTRS)

    Cooper, Charles David (Inventor); Clauseu, christian Anthony (Inventor)

    2005-01-01

    An apparatus for treating pollutants in a gas may include a source of hydrogen peroxide, and a treatment injector for creating and injecting dissociated hydrogen peroxide into the flow of gas. The treatment injector may further include an injector housing having an inlet, an outlet, and a hollow interior extending there between. The inlet may be connected in fluid communication with the source of hydrogen peroxide so that hydrogen peroxide flows through the hollow interior and toward the outlet. At least one ultraviolet (UV) lamp may be positioned within the hollow interior of the injector housing. The at least one UV lamp may dissociate the hydrogen peroxide flowing through the tube. The dissociated hydrogen peroxide may be injected into the flow of gas from the outlet for treating pollutants, such as nitrogen oxides.

  12. Revisiting the mesosome as a novel site of hydrogen peroxide accumulation in Escherichia coli.

    PubMed

    Xin, Li; Lipeng, Yang; Jiaju, Qiao; Hanqing, Feng; Yunhong, Liu; Min, Zhang; Yuxian, Zhang; Hongyu, Li

    2014-10-01

    The major source of endogenous hydrogen peroxide is generally thought to be the respiratory chain of bacteria and mitochondria. In our previous works, mesosome structure was induced in cells during rifampicin effect, and the mesosome formation is always accompanied by excess hydrogen peroxide accumulation in bacterial cells. However, the underlying mechanisms of hydrogen peroxide production and the rationale behind it remain still unknown. Here we report that hydrogen peroxide can specifically accumulate in the mesosome in vitro. Mesosomes were interpreted earlier as artifacts of specific cells under stress through TEM preparation, while, in the current study, mesosomes were shown as intracellular compartments with specific roles and features by using quickly freezing preparation of TEM. Formation of hydrogen peroxide was observed in suspension of mesosomal vesicles by using either a fluorescence-based reporter assay or a histochemical method, respectively. Our investigation provides experimental evidence that mesosomes can be a novel site of hydrogen peroxide accumulation.

  13. Hydrogen peroxide tooth-whitening (bleaching): review of safety in relation to possible carcinogenesis.

    PubMed

    Naik, Supritha; Tredwin, Christopher Jeremy; Scully, Crispian

    2006-08-01

    Hydrogen peroxide in the form of carbamide peroxide is widely used in professionally and self-administered products for tooth whitening. Hydrogen peroxide is a highly reactive substance that can damage oral soft and hard tissues when present in high concentrations and with exposures of prolonged duration. This review examines the issue of oral mucosal damage and possible carcinogenicity relating to the use of hydrogen peroxide in the mouth for tooth whitening, with an emphasis on safety with prolonged exposure to low concentrations of peroxide products.

  14. Hydrogen peroxide in orthopaedic surgery - is it worth the risk?

    PubMed

    Yang, Yi; Reid, Chris; Nambiar, Mithun; Penn, David

    2016-08-01

    Hydrogen peroxide (H2O2) is commonly used in orthopaedic surgery during cemented arthroplasty and wound washouts. Its purported roles include antisepsis, haemostasis, mechanical debridement, and optimising the cement-bone interface during cementing. However, despite its apparent harmless mechanism of action, H2O2 has been implicated in fatal and near fatal complications caused through oxygen emboli. We present a case of oxygen embolism and review the existing literature to highlight its potential risks and its lack of therapeutic value. We believe there is little role for its use in orthopaedic surgery.

  15. Historical Survey: German Research on Hydrogen Peroxide/Alcohol Explosives

    SciTech Connect

    Parmeter, John E.

    2015-01-01

    Discussion of HP/fuel explosives in the scientific literature dates back to at least 1927. A paper was published that year in a German journal entitled On Hydrogen Peroxide Explosives [Bamberger and Nussbaum 1927]. The paper dealt with HP/cotton/Vaseline formulations, specifically HP89/cotton/Vaseline (76/15/9) and (70/8.5/12.5). The authors performed experiments with charge masses of 250-750 g and charge diameters of 35-45 mm. This short paper provides brief discussion on the observed qualitative effects of detonations but does not report detonation velocities.

  16. Hydrogen peroxide agarose gels for electrophoretic analysis of RNA.

    PubMed

    Pandey, Renu; Saluja, Daman

    2017-10-01

    Efficient electrophoretic separation of isolated total RNA utilizes chemicals and agents to aid in nuclease free environment. However cost, extensive pre-run processing protocols as well as toxic byproducts limit the usage of such protocols. Moreover, these treatments affect the overall electrophoretic results by altering the conductivity of the running buffer and weaken the gel strength. We here provide a protocol for RNA visualization that obviates these shortcomings by preparation of agarose gel with hydrogen peroxide using the regular TAE buffer. The simple, inexpensive protocol exhibits superior results in a horizontal agarose gel electrophoresis. Copyright © 2017 Elsevier Inc. All rights reserved.

  17. Hydrogen peroxide-based propulsion and power systems.

    SciTech Connect

    Melof, Brian Matthew; Keese, David L.; Ingram, Brian V.; Grubelich, Mark Charles; Ruffner, Judith Alison; Escapule, William Rusty

    2004-04-01

    Less toxic, storable, hypergolic propellants are desired to replace nitrogen tetroxide (NTO) and hydrazine in certain applications. Hydrogen peroxide is a very attractive replacement oxidizer, but finding acceptable replacement fuels is more challenging. The focus of this investigation is to find fuels that have short hypergolic ignition delays, high specific impulse, and desirable storage properties. The resulting hypergolic fuel/oxidizer combination would be highly desirable for virtually any high energy-density applications such as small but powerful gas generating systems, attitude control motors, or main propulsion. These systems would be implemented on platforms ranging from guided bombs to replacement of environmentally unfriendly existing systems to manned space vehicles.

  18. Hydrogen Peroxide as an Effective Disinfectant for Pasteurella multocida

    PubMed Central

    Jung, In-Soo; Kim, Hyun-Jung; Jung, Won-Yong

    2014-01-01

    Pasteurella multocida (P. multocida) infections vary widely, from local infections resulting from animal bites and scratches to general infections. As of yet, no vaccine against P. multocida has been developed, and the most effective way to prevent pathogenic transmission is to clean the host environment using disinfectants. In this study, we identified which disinfectants most effectively inhibited environmental isolates of P. multocida. Three readily available disinfectants were compared: 3% hydrogen peroxide (HP), 70% isopropyl alcohol, and synthetic phenol. In suspension tests and zone inhibition tests, 3% HP was the most promising disinfectant against P. multocida. PMID:24954350

  19. Iron-catalyzed hydrogen production from formic acid.

    PubMed

    Boddien, Albert; Loges, Björn; Gärtner, Felix; Torborg, Christian; Fumino, Koichi; Junge, Henrik; Ludwig, Ralf; Beller, Matthias

    2010-07-07

    Hydrogen represents a clean energy source, which can be efficiently used in fuel cells generating electricity with water as the only byproduct. However, hydrogen generation from renewables under mild conditions and efficient hydrogen storage in a safe and reversible manner constitute important challenges. In this respect formic acid (HCO(2)H) represents a convenient hydrogen storage material, because it is one of the major products from biomass and can undergo selective decomposition to hydrogen and carbon dioxide in the presence of suitable catalysts. Here, the first light-driven iron-based catalytic system for hydrogen generation from formic acid is reported. By application of a catalyst formed in situ from inexpensive Fe(3)(CO)(12), 2,2':6'2''-terpyridine or 1,10-phenanthroline, and triphenylphosphine, hydrogen generation is possible under visible light irradiation and ambient temperature. Depending on the kind of N-ligands significant catalyst turnover numbers (>100) and turnover frequencies (up to 200 h(-1)) are observed, which are the highest known to date for nonprecious metal catalyzed hydrogen generation from formic acid. NMR, IR studies, and DFT calculations of iron complexes, which are formed under reaction conditions, confirm that PPh(3) plays an active role in the catalytic cycle and that N-ligands enhance the stability of the system. It is shown that the reaction mechanism includes iron hydride species which are generated exclusively under irradiation with visible light.

  20. Catalysis with Cu(II) (bpy) improves alkaline hydrogen peroxide pretreatment.

    PubMed

    Li, Zhenglun; Chen, Charles H; Liu, Tongjun; Mathrubootham, Vaidyanathan; Hegg, Eric L; Hodge, David B

    2013-04-01

    Copper(II) 2,2'-bipyridine (Cu(II) (bpy))-catalyzed alkaline hydrogen peroxide (AHP) pretreatment was performed on three biomass feedstocks including alkali pre-extracted switchgrass, silver birch, and a hybrid poplar cultivar. This catalytic approach was found to improve the subsequent enzymatic hydrolysis of plant cell wall polysaccharides to monosaccharides for all biomass types at alkaline pH relative to uncatalyzed pretreatment. The hybrid poplar exhibited the most significant improvement in enzymatic hydrolysis with monomeric sugar release and conversions more than doubling from 30% to 61% glucan conversion, while lignin solubilization was increased from 36.6% to 50.2% and hemicellulose solubilization was increased from 14.9% to 32.7%. It was found that Cu(II) (bpy)-catalyzed AHP pretreatment of cellulose resulted in significantly more depolymerization than uncatalyzed AHP pretreatment (78.4% vs. 49.4% decrease in estimated degree of polymerization) and that carboxyl content the cellulose was significantly increased as well (fivefold increase vs. twofold increase). Together, these results indicate that Cu(II) (bpy)-catalyzed AHP pretreatment represents a promising route to biomass deconstruction for bioenergy applications. Copyright © 2012 Wiley Periodicals, Inc.

  1. Hydrogen Peroxide Accidents and Incidents: What We Can Learn From History

    NASA Technical Reports Server (NTRS)

    Greene, Ben; Baker, David L.; Frazier, Wayne

    2005-01-01

    Historical accidents and incidents involving hydrogen peroxide are reviewed and presented. These hydrogen peroxide events are associated with storage, transportation, handling, and disposal and they include exposures, fires, and explosions. Understanding the causes and effects of these accident and incident examples may aid personnel currently working with hydrogen peroxide to mitigate and perhaps avoid similar situations. Lessons learned, best practices, and regulatory compliance information related to the cited accidents and incidents are also discussed.

  2. Feasibility of routinely using hydrogen peroxide vapor to decontaminate rooms in a busy United States hospital.

    PubMed

    Otter, Jonathan A; Puchowicz, Matthew; Ryan, David; Salkeld, James A G; Cooper, Timothea A; Havill, Nancy L; Tuozzo, Kathy; Boyce, John M

    2009-06-01

    During a 22-month period at a 500-bed teaching hospital, 1,565 rooms that had housed patients infected with multidrug-resistant pathogens were decontaminated using hydrogen peroxide vapor. Hydrogen peroxide vapor decontamination required a mean time of 2 hours and 20 minutes, compared with 32 minutes for conventional cleaning. Despite the greater time required for decontamination, hydrogen peroxide vapor decontamination of selected patient rooms is feasible in a busy hospital with a mean occupancy rate of 94%.

  3. Hydrogen peroxide induce modifications of human extracellular superoxide dismutase that results in enzyme inhibition.

    PubMed

    Gottfredsen, Randi H; Larsen, Ulrike G; Enghild, Jan J; Petersen, Steen V

    2013-01-01

    Superoxide dismutase (EC-SOD) controls the level of superoxide in the extracellular space by catalyzing the dismutation of superoxide into hydrogen peroxide and molecular oxygen. In addition, the enzyme reacts with hydrogen peroxide in a peroxidase reaction which is known to disrupt enzymatic activity. Here, we show that the peroxidase reaction supports a site-specific bond cleavage. Analyses by peptide mapping and mass spectrometry shows that oxidation of Pro112 supports the cleavage of the Pro112-His113 peptide bond. Substitution of Ala for Pro112 did not inhibit fragmentation, indicating that the oxidative fragmentation at this position is dictated by spatial organization and not by side-chain specificity. The major part of EC-SOD inhibited by the peroxidase reaction was not fragmented but found to encompass oxidations of histidine residues involved in the coordination of copper (His98 and His163). These oxidations are likely to support the dissociation of copper from the active site and thus loss of enzymatic activity. Homologous modifications have also been described for the intracellular isozyme, Cu/Zn-SOD, reflecting the almost identical structures of the active site within these enzymes. We speculate that the inactivation of EC-SOD by peroxidase activity plays a role in regulating SOD activity in vivo, as even low levels of superoxide will allow for the peroxidase reaction to occur.

  4. Effect of hydrogen peroxide and sodium perborate on the microhardness of human enamel and dentin.

    PubMed

    Lewinstein, I; Hirschfeld, Z; Stabholz, A; Rotstein, I

    1994-02-01

    The effect of 30% hydrogen peroxide and a paste of sodium perborate mixed with hydrogen peroxide at different temperatures and time intervals on the microhardness of human enamel and dentin was examined. Intact extracted human teeth were sectioned, embedded in acrylic resin, polished, and divided into four test groups related to surface treatment. The groups were 30% hydrogen peroxide at 37 degrees C, 30% hydrogen peroxide at 50 degrees C in an illuminated chamber, a paste of sodium perborate mixed with hydrogen peroxide at 37 degrees C, and a paste of sodium perborate mixed with hydrogen peroxide at 50 degrees C in an illuminated chamber. Teeth treated with distilled water at either 37 degrees C or 50 degrees C served as controls. The results indicated that treatment with 30% hydrogen peroxide reduced the microhardness of both enamel and dentin. This reduction was statistically significant after 5-min treatment for the dentin and after 15-min treatment for the enamel (p < 0.05). Treatment with sodium perborate mixed with hydrogen peroxide did not alter the microhardness of either the enamel or dentin at the tested temperatures and time intervals. It is therefore suggested that the use of high concentrations of hydrogen peroxide for bleaching purposes should be limited. Sodium perborate appears to be a less damaging bleaching agent.

  5. Hydrogen peroxide production by Lactobacillus johnsonii NCC 533 and its role in anti-Salmonella activity.

    PubMed

    Pridmore, Raymond David; Pittet, Anne-Cécile; Praplan, Fabienne; Cavadini, Christoph

    2008-06-01

    The human intestinal isolate Lactobacillus johnsonii NCC 533 (La1) is a probiotic strain with well-documented antimicrobial properties. Previous research has identified the production of lactic acid and bacteriocins as important factors, but that other unidentified factors are also involved. We used the recently published genome sequence of L. johnsonii NCC 533 to search for novel antipathogen factors and identified three potential gene products that may catalyze the synthesis of the known antimicrobial factor hydrogen peroxide, H(2)O(2). In this work, we confirmed the ability of NCC 533 as well as eight different L. johnsonii strains and Lactobacillus gasseri to produce H(2)O(2) when resting cells were incubated in the presence of oxygen, and that culture supernatant containing NCC 533-produced H(2)O(2) was effective in killing the model pathogen Salmonella enterica serovar Typhimurium SL1344 in vitro.

  6. Identification of hydrogen peroxide-secreting cells by cytocompatible coating with a hydrogel membrane.

    PubMed

    Liu, Yang; Sakai, Shinji; Kawa, Shogo; Taya, Masahito

    2014-12-02

    A method for identifying each cell secreting reactive oxygen species (ROS) is highly desirable to advance the understanding of the physiological and pathological processes attributed to extracellular ROS. Here, we first report a method for realizing this. The individual cells secreting hydrogen peroxide (H2O2), a common ROS, could be coated by a hydrogel membrane through a horseradish peroxidase-catalyzed reaction consuming H2O2 secreted from the cells themselves. This hydrogel membrane coating was proved to be cytocompatible. In addition, the hydrogel membrane made from an alginate derivative could be removed on demand without causing damage to the enclosed cells. These results demonstrated the feasibility of the proposed method to be an effective tool in cellular ROS studies.

  7. Direct reduction of hydrogen peroxides into hydroxyl ions in peroxide-based fuel cells

    NASA Astrophysics Data System (ADS)

    Luo, Nie; Miley, George; Noid, Don; Chubb, Scott

    2004-03-01

    The physics of catalytic electrochemical reduction of hydrogen peroxide (H2O2 + 2 e = 2 OH-) at the electrolyte/cathode interface of peroxide fuel cells is under study. This reaction is ideally suited for high efficiency fuel cell operation, but is nevertheless in competition with wasteful processes such as the direct decomposition of H2O2 to water and oxygen gas. The reaction kinetics of these competing processes are calculated with thermodynamic and electrochemical data of relevant materials, resulting in a qualitative guide to the selection of effective catalyst and cathode compositions. The experimental research includes cyclic voltammetry, used to probe the surface electrochemistry of the catalytic process, and to shed light on how a correct theoretical understanding is restricted experimentally. A fuel cell based on direct hydrogen peroxide cathode has the following distinct advantages: i) Very high volumetric power density (several times higher than conventional H2/O2 fuel cells) due to direct utilization of a liquid phase oxidant at the cathode; (ii) The potential for a very high efficiency (over 60%) because the use of H2O2 overcomes the oxygen over-potential problem (slow O2 reduction kinetics) inherent to a H2/O2 fuel cell designs, which require simultaneous transfer of four electrons; (iii) Safe, and long time stable storage of the energetic materials for fuel cells in special environment (space, underwater, etc.). The measurement on open cell voltage, short-circuit current density shows an improved performance compared to a typical H2/O2 fuel cell, indicating a higher efficiency at similar discharge conditions.

  8. The alpha-hemolysin of Streptococcus gordonii is hydrogen peroxide.

    PubMed Central

    Barnard, J P; Stinson, M W

    1996-01-01

    The alpha-hemolysin of viridans group streptococci, which causes greening of intact erythrocytes, is a potential virulence factor as well as an important criterion for the laboratory identification of these bacteria; however, it has never been purified and characterized. The alpha-hemolysin of Streptococcus gordonii CH1 caused characteristic shifts in the A403, A430, A578, and A630 of sheep hemoglobin. A spectrophotometric assay was developed and used to monitor purification of alpha-hemolysin during extraction in organic solvents and separation by reverse-phase high-performance liquid chromatography (HPLC). The alpha-hemolysin was identical to hydrogen peroxide with respect to its effects on erythrocyte hemoglobin, oxygen-dependent synthesis by streptococci, insensitivity to proteases, inactivation by catalase, differential solubility, failure to adsorb to ion-exchange chromatography resins, and retention time on a reverse-phase HPLC column. The amount of hydrogen peroxide present in HPLC-fractionated spent culture medium was sufficient to account for all alpha-hemolytic activity observed. PMID:8751938

  9. Vapor hydrogen peroxide as alternative to dry heat microbial reduction

    NASA Astrophysics Data System (ADS)

    Chung, S.; Kern, R.; Koukol, R.; Barengoltz, J.; Cash, H.

    The Jet Propulsion Laboratory in conjunction with the NASA Planetary Protection Officer has selected vapor phase hydrogen peroxide sterilization process for continued development as a NASA approved sterilization technique for spacecraft subsystems and systems The goal is to include this technique with appropriate specification in NPG8020 12C as a low temperature complementary technique to the dry heat sterilization process To meet microbial reduction requirements for all Mars in-situ life detection and sample return missions various planetary spacecraft subsystems will have to be exposed to a qualified sterilization process This process could be the elevated temperature dry heat sterilization process 115C for 40 hours which was used to sterilize the Viking lander spacecraft However with utilization of highly sophisticated electronics and sensors in modern spacecraft this process presents significant materials challenges and is thus undesirable to design engineers to achieve bioburden reduction The objective of this work is to introduce vapor hydrogen peroxide VHP as an alternative to dry heat microbial reduction to meet planetary protection requirements The VHP process is widely used by the medical industry to sterilize surgical instruments and biomedical devices but high doses of VHP may degrade the performance of flight hardware or compromise material compatibility Our goal for this study is to determine the minimum VHP process conditions for planetary protection acceptable microbial reduction levels A series of experiments were conducted to

  10. Antifungal efficacy of hydrogen peroxide in dental unit waterline disinfection.

    PubMed

    Szymańska, Jolanta

    2006-01-01

    The concentration and composition of fungal flora in dental unit waterlines (DUWL) were evaluated. For this purpose, water samples from unit reservoirs and high-speed handpieces, and biofilm samples from the waterline walls from units were collected. Subsequently, analogous samples from DUWL were taken before and after disinfection using agent containing hydrogen peroxide. In the examined samples, the yeast-like fungi Candida albicans and Candida curvata were found. The following species of mould were also identified: Aspergillus amstelodami, Aspergillus fumigatus, Aspergillus glaucus group, Aspergillus (=Eurotium herbariorum) repens, Citromyces spp., Geotrichum candidum, Penicillium (glabrum) frequentans, Penicillium pusillum, Penicillium turolense and Sclerotium sclerotiorum (Sclerotinia sclerotiorum). Before disinfection, Candida curvata and Candida albicans constituted the greatest proportion of the total fungi in the reservoirs water; in the water of handpieces--Candida albicans and Aspergillus glaucus group; and in the biofilm samples--Aspergillus glaucus group and Candida albicans. After disinfection, in all 3 kinds of samples, Candida albicans prevailed, constituting from 31.2-85.7 % of the total fungi. The application of agent containing hydrogen peroxide caused a significant decrease both in the number of total fungi and individual fungal species, which confirms the product effectiveness in fungal decontamination of DUWL.

  11. Hydrogen Peroxide and Sodium Transport in the Lung and Kidney

    PubMed Central

    Shlyonsky, V.; Boom, A.; Mies, F.

    2016-01-01

    Renal and lung epithelial cells are exposed to some significant concentrations of H2O2. In urine it may reach 100 μM, while in the epithelial lining fluid in the lung it is estimated to be in micromolar to tens-micromolar range. Hydrogen peroxide has a stimulatory action on the epithelial sodium channel (ENaC) single-channel activity. It also increases stability of the channel at the membrane and slows down the transcription of the ENaC subunits. The expression and the activity of the channel may be inhibited in some other, likely higher, oxidative states of the cell. This review discusses the role and the origin of H2O2 in the lung and kidney. Concentration-dependent effects of hydrogen peroxide on ENaC and the mechanisms of its action have been summarized. This review also describes outlooks for future investigations linking oxidative stress, epithelial sodium transport, and lung and kidney function. PMID:27073804

  12. Effect of Hydrogen Peroxide on the Antibacterial Substantivity of Chlorhexidine

    PubMed Central

    Shahriari, Shahriar; Mohammadi, Zahed; Mokhtari, Mohammadi Mehdi; Yousefi, Rasoul

    2010-01-01

    The purpose of this in vitro study was to assess the effect of hydrogen peroxide on the antibacterial substantivity of chlorhexidine (CHX). Seventy-five dentine tubes prepared from human maxillary central and lateral incisor teeth were used. After contamination with Enterococcus faecalis for 14 days, the specimens were divided into five groups as follows: CHX, H2O2, CHX + H2O2, infected dentine tubes (positive control), and sterile dentine tubes (negative control). Dentine chips were collected with round burs into tryptic soy broth, and after culturing, the number of colony-forming units (CFU) was counted. The number of CFU was minimum in the first cultures in all experimental groups, and the results obtained were significantly different from each other at any time period (P < .05). At the first culture, the number of CFU in the CHX + H2O2 group was lower than other two groups. At the other experimental periods, the CHX group showed the most effective antibacterial action (P < .05). Hydrogen peroxide group showed the worst result at all periods. In each group, the number of CFU increased significantly by time lapse (P < .05). In conclusion, H2O2 had no additive effect on the residual antibacterial activity of CHX. PMID:21318180

  13. A low-volume microstructured optical fiber hydrogen peroxide sensor

    NASA Astrophysics Data System (ADS)

    Schartner, E. P.; Murphy, D. F.; Ebendorff-Heidepriem, H.; Monro, T. M.

    2011-05-01

    The ability to measure the concentration of hydrogen peroxide (H2O2) in solution is critical for quality assessment and control in many disparate applications, including wine, aviation fuels and IVF. The objective of this research is to develop a rapid test for the hydrogen peroxide content that can be performed on very low volume samples (i.e. sub-μL) that is relatively independent of other products within the sample. For H2O2 detection we use suspended core optical fibers to achieve a high evanescent field interaction with the fluid of interest, without the constraint of limited interaction length that is generally inherent with nanowire structures. By filling the holes of the fiber with an analyte/fluorophore solution we seek to create a quick and effective sensor that should enable detection of desired species within liquid media. By choosing a fluorophore that reacts with our target species to produce an increase in fluorescence, we can correlate observed fluorescence intensity with the concentration of the target molecule.

  14. Dissolution of ion exchange resin by hydrogen peroxide

    SciTech Connect

    Lee, S.C.

    1981-08-01

    The resin dissolution process was conducted successfully in full-scale equipment at the SRL Semiworks. A solution containing 0.001M Fe/sup 2 +/, or Fe/sup 3 +/, and 3 vol % H/sub 2/O/sub 2/ in 0.1M HNO/sub 3/ is sufficient to dissolve up to 40 vol % resin slurry (Dowex 50W-X8). Foaming and pressurization can be eliminated by maintaining the dissolution temperature below 99/sup 0/C. The recommended dissolution temperature range is 85 to 90/sup 0/C. Premixing hydrogen peroxide with all reactants will not create a safety hazard, but operating with a continual feed of hydrogen peroxide is recommended to control the dissolution rate. An air sparging rate of 1.0 to 1.5 scfm will provide sufficient mixing. Spent resin from chemical separation contains DTPA (diethylenetriaminepentaacetic acid) residue, and the resin must be washed with 0.1M NH/sub 4/ OH to remove excess DTPA before dissolution. Gamma irradiation of resin up to 4 kW-hr/L did not change the dissolution rate significantly.

  15. Effect of species, life stage, and water temperature on the toxicity of hydrogen peroxide to fish

    USGS Publications Warehouse

    Rach, J.J.; Schreier, T.M.; Howe, G.E.; Redman, S.D.

    1997-01-01

    Hydrogen peroxide is a drug of low regulatory priority status that is effective in treating fish and fish eggs infected by fungi. However, only limited information is available to guide fish culturists in administering hydrogen peroxide to diseased fish. Laboratory tests were conducted to determine (1) the sensitivity of brown trout Salmo trutta, lake trout Salvelinus namaycush, fathead minnow Pimephales promelas, walleye Stizostedion vitreum, channel catfish Ictalurus punctatus, and bluegill Lepomis, machrochirus to hydrogen peroxide treatments; (2) the sensitivity of various life stages of rainbow trout Oncorhynchus mykiss to hydrogen peroxide treatments; and (3) the effect of water temperature on the acute toxicity of hydrogen peroxide to three fish species. Fish were exposed to hydrogen peroxide concentrations ranging from 100 to 5,000 mu L/L (ppm) for 15-min or 45-min treatments every other day for four consecutive treatments to determine the sensitivity of various species and life stages of fish. Except for walleye, most species of fish tested (less than or equal to 2 g) tolerated hydrogen peroxide of 1,000 mu L/L or greater. Walleyes were sensitive to hydrogen peroxide concentrations as low as 100 mu L/L. A correlation was found between the toxicity of hydrogen peroxide and the life stages of rainbow trout; larger fish were more sensitive. Generally, the toxicity of hydrogen peroxide increased for all species as water temperature increased. The results of these experiments demonstrate that it is important to consider the effects of species, life stage, and water temperature when conducting hydrogen peroxide treatments.

  16. Removal of multiple air pollutants by gas-phase reactions of hydrogen peroxide

    SciTech Connect

    Zamansky, V.M.; Ho, L.; Maly, P.M.; Seeker, W.R.

    1995-12-31

    Hydrogen peroxide is a large-volume chemical with a wide range of applications in different industries. If properly stored, hydrogen peroxide solutions in water are stable, with no loss of the effective substance. Environmental applications have become a major area of use for hydrogen peroxide because it is not itself a source of pollution, and water and oxygen are the only reaction by- products. There is a variety of developed or developing environmental technologies which use H{sub 2}O{sub 2} as an active reagent: detoxification and deodorization of industrial and municipal effluents; low temperature removal of nitrogen oxides, sulfur dioxide, cyanides, chlorine, hydrogen sulfide, organic compounds; low temperature treatment for catalytic NO-to-NO{sub 2} conversion, etc. This study develops a concept of high-temperature hydrogen peroxide injection into combustion gases or other off-gases followed by reactions of hydrogen peroxide with nitric oxide, sulfur trioxide, carbon monoxide and organic compounds.

  17. Effectiveness of treatment with carbamide peroxide and hydrogen peroxide in subjects affected by dental fluorosis: a clinical trial.

    PubMed

    Loyola-Rodriguez, Juan Pablo; Pozos-Guillen, Amaury de Jesus; Hernandez-Hernandez, Felipe; Berumen-Maldonado, Rocio; Patiño-Marin, Nuria

    2003-01-01

    Dental fluorosis is an endemic dental health problem around the world; so, it is important to develop clinical alternatives that are non-invasive and inexpensive. In this study, nightguard vital bleaching technique (NVBT), using carbamide and hydrogen peroxide as active agents, has shown itself to be effective in whitening teeth affected by dental fluorosis. Carbamide peroxide at 10 and 20% and hydrogen peroxide at 7.5% showed good clinical effectiveness in improving clinical appearence, but it is important to point out that clinical success is only in cases of class 1 to 3 of the Tooth Surface Index of Fluorosis. When comparing 10 and 20% concentrations of carbamide peroxide, there was no difference in the clinical effectiveness (p > 0.05); but when comparing both concentrations of carbamide peroxide against hydrogen peroxide, results showed that carbamide peroxide was more effective in whitening in cases of dental fluorosis, the difference being statistically significant (p < 0.05). NVBT has two advantages: it is a non-invasive technique and the relationship cost/benefit is excellent; only a few patients reported tenderness or mild tooth sensitivity.

  18. An optimized hydrogen target for muon catalyzed fusion

    NASA Astrophysics Data System (ADS)

    Gheisari, R.

    2011-04-01

    This paper deals with the optimization of the processes involved in muon catalyzed fusion. Muon catalyzed fusion ( μCF) is studied in all layers of the solid hydrogen structure H/0.1%T⊕D2⊕HD. The layer H/ T acts as an emitter source of energetic tμ atoms, due to the so-called Ramsauer-Townsend effect. These tμ atoms are slowed down in the second layer (degrader) and are forced to take place nuclear fusion in HD. The degrader affects time evolution of tμ atomic beam. This effect has not been considered until now in μCF-multilayered targets. Due to muon cycling and this effect, considerable reactions occur in the degrader. In our calculations, it is shown that the fusion yield equals 180±1.5. It is possible to separate events that overlap in time.

  19. Oxygen from Hydrogen Peroxide. A Safe Molar Volume-Molar Mass Experiment.

    ERIC Educational Resources Information Center

    Bedenbaugh, John H.; And Others

    1988-01-01

    Describes a molar volume-molar mass experiment for use in general chemistry laboratories. Gives background technical information, procedures for the titration of aqueous hydrogen peroxide with standard potassium permanganate and catalytic decomposition of hydrogen peroxide to produce oxygen, and a discussion of the results obtained in three…

  20. An Experimental Investigation of Hypergolic Ignition Delay of Hydrogen Peroxide with Fuel Mixtures

    NASA Technical Reports Server (NTRS)

    Blevins, John A.; Gostowski, Rudy; Chianese, Silvio

    2003-01-01

    An experimental evaluation of decomposition and ignition delay of hydrogen peroxide at concentrations of 80% to 98% with combinations of hydrocarbon fuels, tertiary amines and transition metal chelates will be presented in the proposed paper. The results will be compared to hydrazine ignition delays with hydrogen peroxide and nitric acid mixtures using the same test apparatus.

  1. Mycobactericidal activity of hydrogen peroxide activated by a novel heterogeneous Fentons-like catalyst system.

    PubMed

    Price, S L; Huddersman, K D; Shen, J; Walsh, S E

    2013-02-01

    To investigate the potential activation of hydrogen peroxide by a novel catalyst, reducing the concentration of hydrogen peroxide required and the time taken for mycobactericidal activity. The mycobactericidal properties of an iron-based novel heterogeneous-modified polyacrylonitrile (PAN) catalyst in combination with hydrogen peroxide were examined against Mycobacterium chelonae using a modified version of the European suspension test. Mycobactericidal activity was significantly increased when the modified PAN catalyst was combined with hydrogen peroxide. The 0·5% w/v hydrogen peroxide and 2-g catalyst system resulted in average Log reductions of >5·80 for Myco. chelonae at 30-min exposure at room temperature. This was a significant increase in activity (P < 0·01) compared to 0·5% w/v hydrogen peroxide alone. This study has expanded on previous work and knowledge of the modified PAN catalyst and hydrogen peroxide system, by providing evidence for mycobactericidal activity when the novel PAN catalyst is combined with hydrogen peroxide. © 2012 The Society for Applied Microbiology.

  2. Hydrogen peroxide and povidone-lodine solution--a dangerous combination.

    PubMed

    2011-02-01

    When mixed with povidone-iodine solution, hydrogen peroxide can release enough oxygen to cause sealed waste containers to burst open. Such risks can also result from using a sealed container to collect hydrogen peroxide that has mixed with body fluids (for instance, in a debridement procedure). Staff should be instructed to avoid both practices.

  3. 21 CFR 172.167 - Silver nitrate and hydrogen peroxide solution.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... reference in accordance with 5 U.S.C. 552(a) and 1 CFR part 51. You may obtain copies from the United States...: http://www.archives.gov/federal-register/cfr/ibr-locations.html. (c) The amount of silver added will... Hydrogen Peroxide Test Kit from the HACH Co., or equivalent. The manual from the Hydrogen Peroxide Test...

  4. Development of vapor phase hydrogen peroxide sterilization process for spacecraft applications

    NASA Technical Reports Server (NTRS)

    Rohatgi, N.; Schubert, W.; Knight, J.; Quigley, M.; Forsberg, G.; Ganapathi, G.; Yarbrough, C.; Koukol, R.

    2001-01-01

    This paper will present test data and discussion on the work we are conducting at JPL to address the following issues: 1) efficacy of sterilization process; 2) diffusion of hydrogen peroxide under sterilization process conditions into hard to reach places; 3) materials and components compatibility with the sterilization process and 4) development of methodology to protect sensitive components from hydrogen peroxide vapor.

  5. Oxygen from Hydrogen Peroxide. A Safe Molar Volume-Molar Mass Experiment.

    ERIC Educational Resources Information Center

    Bedenbaugh, John H.; And Others

    1988-01-01

    Describes a molar volume-molar mass experiment for use in general chemistry laboratories. Gives background technical information, procedures for the titration of aqueous hydrogen peroxide with standard potassium permanganate and catalytic decomposition of hydrogen peroxide to produce oxygen, and a discussion of the results obtained in three…

  6. Hydrogen peroxide and caustic soda: Dancing with a dragon while bleaching

    Treesearch

    Peter W. Hart; Carl Houtman; Kolby Hirth

    2013-01-01

    When hydrogen peroxide is mixed with caustic soda, an auto-accelerating reaction can lead to generation of significant amounts of heat and oxygen. On the basis of experiments using typical pulp mill process concentration and temperatures, a relatively simple kinetic model has been developed. Evaluation of these model results reveals that hydrogen peroxide-caustic soda...

  7. Development of vapor phase hydrogen peroxide sterilization process for spacecraft applications

    NASA Technical Reports Server (NTRS)

    Rohatgi, N.; Schubert, W.; Knight, J.; Quigley, M.; Forsberg, G.; Ganapathi, G.; Yarbrough, C.; Koukol, R.

    2001-01-01

    This paper will present test data and discussion on the work we are conducting at JPL to address the following issues: 1) efficacy of sterilization process; 2) diffusion of hydrogen peroxide under sterilization process conditions into hard to reach places; 3) materials and components compatibility with the sterilization process and 4) development of methodology to protect sensitive components from hydrogen peroxide vapor.

  8. Role of hydrogen peroxide and hydroxyl radical in pyrite oxidation by molecular oxygen

    NASA Astrophysics Data System (ADS)

    Schoonen, Martin A. A.; Harrington, Andrea D.; Laffers, Richard; Strongin, Daniel R.

    2010-09-01

    Hydrogen peroxide and hydroxyl radical are readily formed during the oxidation of pyrite with molecular oxygen over a wide range of pH conditions. However, pretreatment of the pyrite surface influences how much of the intermediates are formed and their fate. Acid-washed pyrite produces significant amounts of hydrogen peroxide and hydroxyl radical when suspended in air-saturated water. However, the hydrogen peroxide concentration shows an exponential decrease with time. Suspensions made with partially oxidized pyrite yield significantly lower amounts of hydrogen peroxide product. The presence of Fe(III)-oxide or Fe(III)-hydroxide patches facilitates the conversion of hydrogen peroxide to oxygen and water. Hence, the degree to which a pyrite surface is covered with patches of Fe(III)-oxide or Fe(III)-hydroxide patches is an important control on the concentration of hydrogen peroxide in solution. Hydrogen peroxide appears to be an important intermediate in the four-electron transfer from pyrite to molecular oxygen. Addition of catalase, an enzyme that decomposes hydrogen peroxide to water and molecular oxygen, to a pyrite suspension reduces the oxidation rate by 40%. By contrast, hydroxyl radical does not appear to play a significant role in the oxidation mechanism. It is estimated on the basis of a molecular oxygen and sulfate mass balance that 5-6% of the molecular oxygen is consumed without forming sulfate.

  9. Lgr4 Expression in Osteoblastic Cells Is Suppressed by Hydrogen Peroxide Treatment.

    PubMed

    Pawaputanon Na Mahasarakham, Chantida; Izu, Yayoi; Nishimori, Katsuhiko; Izumi, Yuichi; Noda, Masaki; Ezura, Yoichi

    2017-07-01

    LGR4 is expressed in bone and has been shown to be involved in bone metabolism. Oxidative stress is one of the key issues in pathophysiology of osteoporosis. However, the link between Lgr4 and oxidative stress has not been known. Therefore, effects of hydrogen peroxide on Lgr4 expression in osteoblasts were examined. Hydrogen peroxide treatment suppressed the levels of Lgr4 mRNA expression in an osteoblastic cell line, MC3T3-E1. The suppressive effects were not obvious at 0.1 mM, while 1 mM hydrogen peroxide suppressed Lgr4 expression by more than 50%. Hydrogen peroxide treatment suppressed Lgr4 expression within 12 h and this suppression lasted at least up to 48 h. Hydrogen peroxide suppression of Lgr4 expression was still observed in the presence of a transcription inhibitor but was no longer observed in the presence of a protein synthesis inhibitor. Although Lgr4 expression in osteoblasts is enhanced by BMP2 treatment as reported before, hydrogen peroxide treatment suppressed Lgr4 even in the presence of BMP2. Finally, hydrogen peroxide suppressed Lgr4 expression in primary cultures of osteoblasts similarly to MC3T3-E1 cells. These date indicate that hydrogen peroxide suppresses Lgr4 expression in osteoblastic cells. J. Cell. Physiol. 232: 1761-1766, 2017. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

  10. [The origin of hydrogen peroxide in oral cavity and its role in oral microecology balance].

    PubMed

    Keke, Zhang; Xuedong, Zhou; Xin, Xu

    2017-04-01

    Hydrogen peroxide, an important antimicrobial agent in oral cavity, plays a significant role in the balance of oral microecology. At the early stage of biofilm formation, about 80% of the detected initial colonizers belong to the genus Streptococcus. These oral streptococci use different oxidase to produce hydrogen peroxide. Recent studies showed that the produced hydrogen peroxide plays a critical role in modulating oral microecology. Hydrogen peroxide modulates biofilm development attributed to its growth inhibitory nature. Hydrogen peroxide production is closely associated with extracellular DNA(eDNA) release from microbe and the development of its competent cell which are critical for biofilm development and also serves as source for horizontal gene transfer. Microbe also can reduce the damage to themselves through several detoxification mechanisms. Moreover, hydrogen peroxide is also involved in the regulation of interactions between oral microorganisms and host. Taken together, hydrogen peroxide is an imperative ecological factor that contributes to the microbial equilibrium in the oral cavity. Here we will give a brief review of both the origin and the function in the oral microecology balance of hydrogen peroxide.

  11. Rational Design of a Fluorescent Hydrogen Peroxide Probe Based on the Umbelliferone Fluorophore

    PubMed Central

    Du, Lupei; Li, Minyong; Zheng, Shilong; Wang, Binghe

    2008-01-01

    In this study, we report a novel water-soluble umbelliferone-based fluorescent probe for hydrogen peroxide. This probe shows very large increases (up to 100 fold) in fluorescent intensity upon reaction with hydrogen peroxide, and good selectivity over other reactive oxygen species (ROS). PMID:19081820

  12. A Link between Protein Structure and Enzyme Catalyzed Hydrogen Tunneling

    NASA Astrophysics Data System (ADS)

    Bahnson, Brian J.; Colby, Thomas D.; Chin, Jodie K.; Goldstein, Barry M.; Klinman, Judith P.

    1997-11-01

    We present evidence that the size of an active site side chain may modulate the degree of hydrogen tunneling in an enzyme-catalyzed reaction. Primary and secondary kH/kT and kD/kT kinetic isotope effects have been measured for the oxidation of benzyl alcohol catalyzed by horse liver alcohol dehydrogenase at 25 degrees C. As reported in earlier studies, the relationship between secondary kH/kT and kD/kT isotope effects provides a sensitive probe for deviations from classical behavior. In the present work, catalytic efficiency and the extent of hydrogen tunneling have been correlated for the alcohol dehydrogenase-catalyzed hydride transfer among a group of site-directed mutants at position 203. Val-203 interacts with the opposite face of the cofactor NAD+ from the alcohol substrate. The reduction in size of this residue is correlated with diminished tunneling and a two orders of magnitude decrease in catalytic efficiency. Comparison of the x-ray crystal structures of a ternary complex of a high-tunneling (Phe-93 --> Trp) and a low-tunneling (Val-203 --> Ala) mutant provides a structural basis for the observed effects, demonstrating an increase in the hydrogen transfer distance for the low-tunneling mutant. The Val-203 --> Ala ternary complex crystal structure also shows a hyperclosed interdomain geometry relative to the wild-type and the Phe-93 --> Trp mutant ternary complex structures. This demonstrates a flexibility in interdomain movement that could potentially narrow the distance between the donor and acceptor carbons in the native enzyme and may enhance the role of tunneling in the hydride transfer reaction.

  13. Peroxide test strips detect added hydrogen peroxide in raw milk at levels affecting bacterial load.

    PubMed

    Martin, Nicole H; Friedlander, Adam; Mok, Allen; Kent, David; Wiedmann, Martin; Boor, Kathryn J

    2014-10-01

    Hydrogen peroxide (H2O2) has a long-established history of use as a preservative in milk worldwide. The use of H2O2 to activate the inherent lactoperoxidase enzyme system has dramatically improved the quality of raw dairy products in areas in which cooling is not widely available. In the United States, however, where refrigeration is widely available, the addition of H2O2 to milk is not permitted, with the exception of certain applications prior to cheesemaking and during the preparation of modified whey. Due to the relatively quick deterioration of H2O2 in fluid milk, the detection of raw milk adulterated with the compound can be challenging. In this study we evaluated (i) total aerobic bacterial counts and (ii) ability of peroxide test strips to detect H2O2 in raw milk with various concentrations (0, 100, 300, 500, 700, and 900 ppm) of added H2O2, incubated at both 6 and 21°C for 0, 24, and 48 h. Results showed that at both 6 and 21°C the H2O2 concentration and time had a significant effect on bacterial loads in raw milk. Additionally, commercially available test strips were able to detect H2O2 in raw milk, with predicted probability of >90%, immediately after addition and after 24 and 48 h for the higher concentrations used, offering a viable method for detecting raw milk adulteration with H2O2.

  14. Hydrogen peroxide as a new defensive compound in "benzoyl cyanide" producing polydesmid millipedes

    NASA Astrophysics Data System (ADS)

    Kuwahara, Yasumasa; Yamaguchi, Takuya; Ichiki, Yayoi; Tanabe, Tsutomu; Asano, Yasuhisa

    2017-04-01

    Hydrogen peroxide was newly and simultaneously demonstrated with well-known hydrogen cyanide as a component of defensive secretions of "benzoyl cyanide" producing polydesmid millipedes. Presence of hydrogen peroxide was successively evidenced by Trinder reagent's spray with colorless as well as oily smears of defensive secretions containing benzoyl cyanide and hydrogen cyanide by alkaline picrate paper treatment. Linear correlation was demonstrated between quantities of hydrogen peroxide and benzoyl cyanide. By qualitative assay, seven benzoyl cyanide containing polydesmidans (six species of adults and one species of a nymph at stadium I) tested positive to Trinder reagent, indicative of the presence of hydrogen peroxide (together with hydrogen cyanide), while two cyanogenic species without benzoyl cyanide exhibited negative responses to the reagent. Two types of millipedes were elucidated as species of cyanogenic Polydesmida.

  15. Hydrogen peroxide as a new defensive compound in "benzoyl cyanide" producing polydesmid millipedes.

    PubMed

    Kuwahara, Yasumasa; Yamaguchi, Takuya; Ichiki, Yayoi; Tanabe, Tsutomu; Asano, Yasuhisa

    2017-04-01

    Hydrogen peroxide was newly and simultaneously demonstrated with well-known hydrogen cyanide as a component of defensive secretions of "benzoyl cyanide" producing polydesmid millipedes. Presence of hydrogen peroxide was successively evidenced by Trinder reagent's spray with colorless as well as oily smears of defensive secretions containing benzoyl cyanide and hydrogen cyanide by alkaline picrate paper treatment. Linear correlation was demonstrated between quantities of hydrogen peroxide and benzoyl cyanide. By qualitative assay, seven benzoyl cyanide containing polydesmidans (six species of adults and one species of a nymph at stadium I) tested positive to Trinder reagent, indicative of the presence of hydrogen peroxide (together with hydrogen cyanide), while two cyanogenic species without benzoyl cyanide exhibited negative responses to the reagent. Two types of millipedes were elucidated as species of cyanogenic Polydesmida.

  16. Metal-catalyzed oxidation of 2-alkenals generates genotoxic 4-oxo-2-alkenals during lipid peroxidation.

    PubMed

    Nuka, Erika; Tomono, Susumu; Ishisaka, Akari; Kato, Yoji; Miyoshi, Noriyuki; Kawai, Yoshichika

    2016-10-01

    Lipid peroxidation products react with cellular molecules, such as DNA bases, to form covalent adducts, which are associated with aging and disease processes. Since lipid peroxidation is a complex process and occurs in multiple stages, there might be yet unknown reaction pathways. Here, we analyzed comprehensively 2'-deoxyguanosine (dG) adducts with oxidized arachidonic acid using liquid chromatography-tandem mass spectrometry and found the formation of 7-(2-oxo-hexyl)-etheno-dG as one of the major unidentified adducts. The formation of this adduct was reproduced in the reaction of dG with 2-octenal and predominantly with 4-oxo-2-octenal (OOE). We also found that other 2-alkenals (with five or more carbons) generate corresponding 4-oxo-2-alkenal-type adducts. Importantly, it was found that transition metals enhanced the oxidation of C4-position of 2-octenal, leading to the formation of OOE-dG adduct. These findings demonstrated a new pathway for the formation of 4-oxo-2-alkenals during lipid peroxidation and might provide a mechanism for metal-catalyzed genotoxicity.

  17. Fe-catalyzed etching of exfoliated graphite through carbon hydrogenation

    PubMed Central

    Cheng, Guangjun; Calizo, Irene; Hacker, Christina A.; Richter, Curt A.; Hight Walker, Angela R.

    2016-01-01

    We present an investigation on Fe-catalyzed etching of graphite by dewetting Fe thin films on graphite in forming gas. Raman mapping of the etched graphite shows thickness variation in the etched channels and reveals that the edges are predominately terminated in zigzag configuration. X-ray diffraction and photoelectron spectroscopy measurements identify that the catalytic particles are Fe with the presence of iron carbide and iron oxides. The existence of iron carbide indicates that, in additional to carbon hydrogenation, carbon dissolution into Fe is also involved during etching. Furthermore, the catalytic particles can be re-activated upon a second annealing in forming gas. PMID:27840449

  18. Efficacy of Mouthwashes Containing Hydrogen Peroxide on Tooth Whitening.

    PubMed

    Karadas, Muhammet; Hatipoglu, Omer

    2015-01-01

    The aim of this study was to analyze the efficacy of mouthwashes containing hydrogen peroxide compared with 10% carbamide peroxide (CP) gel. Fifty enamel-dentin samples were obtained from bovine incisors and then stained in a tea solution. The stained samples were randomly divided into five groups according to the whitening product applied (n = 10): AS: no whitening (negative control), with the samples stored in artificial saliva; CR: Crest 3D White mouthwash; LS: Listerine Whitening mouthwash; SC: Scope White mouthwash; and OP group: 10% CP Opalescence PF (positive control). Color measurements were carried out with a spectrophotometer before staining, after staining, and on the 7th, 28th, and 56th day of the whitening period. The data were analyzed using two-way analysis of variance followed by a Tukey post hoc test. The color change (ΔE) was significantly greater in all the groups compared to that of the AS group. After 56 days, no significant differences were found among the mouthwash products with respect to color change (P > 0.05). The whiteness of the teeth treated with the mouthwashes increased significantly over time. Nevertheless, the color change achieved with the mouthwashes was significantly lower than that achieved with the 10% CP at-home bleaching gel.

  19. Efficacy of Mouthwashes Containing Hydrogen Peroxide on Tooth Whitening

    PubMed Central

    Karadas, Muhammet; Hatipoglu, Omer

    2015-01-01

    The aim of this study was to analyze the efficacy of mouthwashes containing hydrogen peroxide compared with 10% carbamide peroxide (CP) gel. Fifty enamel-dentin samples were obtained from bovine incisors and then stained in a tea solution. The stained samples were randomly divided into five groups according to the whitening product applied (n = 10): AS: no whitening (negative control), with the samples stored in artificial saliva; CR: Crest 3D White mouthwash; LS: Listerine Whitening mouthwash; SC: Scope White mouthwash; and OP group: 10% CP Opalescence PF (positive control). Color measurements were carried out with a spectrophotometer before staining, after staining, and on the 7th, 28th, and 56th day of the whitening period. The data were analyzed using two-way analysis of variance followed by a Tukey post hoc test. The color change (ΔE) was significantly greater in all the groups compared to that of the AS group. After 56 days, no significant differences were found among the mouthwash products with respect to color change (P > 0.05). The whiteness of the teeth treated with the mouthwashes increased significantly over time. Nevertheless, the color change achieved with the mouthwashes was significantly lower than that achieved with the 10% CP at-home bleaching gel. PMID:26295061

  20. Evaluating different concentrations of hydrogen peroxide in an automated room disinfection system.

    PubMed

    Murdoch, L E; Bailey, L; Banham, E; Watson, F; Adams, N M T; Chewins, J

    2016-09-01

    A comparative study was made on the efficacy of 5, 10 and 35% weight by weight (w/w) hydrogen peroxide solutions when applied using an automated room disinfection system. Six-log biological indicators of methicillin-resistant Staphylococcus aureus (MRSA) and Geobacillus stearothermophilus were produced on stainless steel coupons and placed within a large, sealed, environmentally controlled enclosure. Five percent hydrogen peroxide was distributed throughout the enclosure using a Bioquell hydrogen peroxide vapour generator (BQ-50) for 40 min and left to reside for a further 200 min. Biological indicators were removed at 10-min intervals throughout the first 120 min of the process. The experiment was repeated for 10 and 35% hydrogen peroxide solutions. Five percent and 10% hydrogen peroxide solutions failed to achieve any reduction of MRSA, but achieved full kill of G. stearothermophilus spores at 70 and 40 min respectively. Thirty-five percent hydrogen peroxide achieved a 6-log reduction of MRSA after 30 min and full kill of G. stearothermophilus at 20 min. The concentration of 5% hydrogen peroxide within the enclosure after the 200-min dwell was measured at 9·0 ppm. This level exceeds the 15-min Short Term Exposure Limit (STEL) for hydrogen peroxide of 2·0 ppm. Users of automated hydrogen peroxide disinfection systems should review system efficacy and room re-entry protocols in light of these results. This research allows hospital infection control teams to consider the impact and risks of using low concentrations of hydrogen peroxide for disinfection within their facilities, and to question automated room disinfection system providers on the efficacy claims they make. The evidence that low concentration hydrogen peroxide solutions do not rapidly, autonomously break down, is in contradiction to the claims made by some hydrogen peroxide equipment providers and raises serious health and safety concerns. Facilities using hydrogen peroxide systems that

  1. Alkaline hydrogen peroxide pretreatment of softwood: hemicellulose degradation pathways.

    PubMed

    Alvarez-Vasco, Carlos; Zhang, Xiao

    2013-12-01

    This study investigated softwood hemicelluloses degradation pathways during alkaline hydrogen peroxide (AHP) pretreatment of Douglas fir. It was found that glucomannan is much more susceptible to alkaline pretreatment than xylan. Organic acids, including lactic, succinic, glycolic and formic acid are the predominant products from glucomannan degradation. At low treatment temperature (90°C), a small amount of formic acid is produced from glucomannan, whereas glucomannan degradation to lactic acid and succinic acid becomes the main reactions at 140°C and 180°C. The addition of H2O2 during alkaline pretreatment of D. fir led to a significant removal of lignin, which subsequently facilitated glucomannan solubilization. However, H2O2 has little direct effect on the glucomannan degradation reaction. The main degradation pathways involved in glucomannan conversion to organics acids are elucidated. The results from this study demonstrate the potential to optimize pretreatment conditions to maximize the value of biomass hemicellulose.

  2. Vapor Hydrogen Peroxide as Alternative to Dry Heat Microbial Reduction

    NASA Technical Reports Server (NTRS)

    Cash, Howard A.; Kern, Roger G.; Chung, Shirley Y.; Koukol, Robert C.; Barengoltz, Jack B.

    2006-01-01

    The Jet Propulsion Laboratory, in conjunction with the NASA Planetary Protection Officer, has selected vapor phase hydrogen peroxide (VHP) sterilization process for continued development as a NASA approved sterilization technique for spacecraft subsystems and systems. The goal is to include this technique, with appropriate specification, in NPG8020.12C as a low temperature complementary technique to the dry heat sterilization process. A series of experiments were conducted in vacuum to determine VHP process parameters that provided significant reductions in spore viability while allowing survival of sufficient spores for statistically significant enumeration. With this knowledge of D values, sensible margins can be applied in a planetary protection specification. The outcome of this study provided an optimization of test sterilizer process conditions: VHP concentration, process duration, a process temperature range for which the worst case D value may be imposed, a process humidity range for which the worst case D value may be imposed, and robustness to selected spacecraft material substrates.

  3. Kinetics of hydrogen peroxide decomposition by catalase: hydroxylic solvent effects.

    PubMed

    Raducan, Adina; Cantemir, Anca Ruxandra; Puiu, Mihaela; Oancea, Dumitru

    2012-11-01

    The effect of water-alcohol (methanol, ethanol, propan-1-ol, propan-2-ol, ethane-1,2-diol and propane-1,2,3-triol) binary mixtures on the kinetics of hydrogen peroxide decomposition in the presence of bovine liver catalase is investigated. In all solvents, the activity of catalase is smaller than in water. The results are discussed on the basis of a simple kinetic model. The kinetic constants for product formation through enzyme-substrate complex decomposition and for inactivation of catalase are estimated. The organic solvents are characterized by several physical properties: dielectric constant (D), hydrophobicity (log P), concentration of hydroxyl groups ([OH]), polarizability (α), Kamlet-Taft parameter (β) and Kosower parameter (Z). The relationships between the initial rate, kinetic constants and medium properties are analyzed by linear and multiple linear regression.

  4. Hydrogen peroxide room disinfection--ready for prime time?

    PubMed

    Huttner, Benedikt D; Harbarth, Stephan

    2015-05-08

    Non-manual techniques for terminal disinfection of hospital rooms have gained increasing interest in recent years as means to reduce transmission of multidrug-resistant organisms (MDROs). A prospective crossover study by Blazejewski and colleagues in five ICUs of a French academic hospital with a high prevalence of MDRO carriers showed that two different hydrogen peroxide (H2O2)-based non-touch disinfection techniques reduced environmental contamination with MDROs after routine cleaning. This study provides further evidence of the 'in use' bioburden reduction offered by these techniques. Before H2O2-based non-touch disinfection can be recommended for routine clinical use outside specific outbreak situations, further studies need to show whether the environmental contamination reduction provided by these techniques is clinically relevant and results in reduced cross-infections with MDROs.

  5. Radiation Hormesis: The Link to Nanomolar Hydrogen Peroxide.

    PubMed

    Sies, Helmut; Feinendegen, Ludwig E

    2017-09-20

    Hydrogen peroxide (H2O2) is a stable product of water radiolysis, occurring at nanomolar concentration upon low-dose ionizing radiation (LDIR) (<100 mGy). In view of the recent recognition of H2O2 as a central redox signaling molecule that, likewise, is maintained in the nanomolar range in cells, we propose a role for H2O2 in radiation hormesis. LDIR is capable of utilizing known molecular redox master switches such as Nrf2/Keap1 or NF-κB/IκB to effect adaptive resistance. This leads to the hypothesis that, as a normal component of the exposome, LDIR mediates hormetic effects by H2O2 signaling. Antioxid. Redox Signal. 27, 596-598.

  6. Recent advances in electrochemical sensing for hydrogen peroxide: a review.

    PubMed

    Chen, Wei; Cai, Shu; Ren, Qiong-Qiong; Wen, Wei; Zhao, Yuan-Di

    2012-01-07

    Due to the significance of hydrogen peroxide (H(2)O(2)) in biological systems and its practical applications, the development of efficient electrochemical H(2)O(2) sensors holds a special attraction for researchers. Various materials such as Prussian blue (PB), heme proteins, carbon nanotubes (CNTs) and transition metals have been applied to the construction of H(2)O(2) sensors. In this article, the electrocatalytic H(2)O(2) determinations are mainly focused on because they can provide a superior sensing performance over non-electrocatalytic ones. The synergetic effect between nanotechnology and electrochemical H(2)O(2) determination is also highlighted in various aspects. In addition, some recent progress for in vivo H(2)O(2) measurements is also presented. Finally, the future prospects for more efficient H(2)O(2) sensing are discussed.

  7. Decomposition of solid amorphous hydrogen peroxide by ion irradiation

    SciTech Connect

    Loeffler, Mark J.; Teolis, Ben D.; Baragiola, Raul A.

    2006-03-14

    We present laboratory studies of the radiolysis of pure (97%) solid H{sub 2}O{sub 2} films by 50 keV H{sup +} at 17 K. Using UV-visible and infrared reflectance spectroscopies, a quartz-crystal microbalance, and a mass spectrometer, we measured the absolute concentrations of the H{sub 2}O, O{sub 2}, H{sub 2}O{sub 2}, and O{sub 3} products as a function of irradiation fluence. Ozone was identified by both UV and infrared spectroscopies and O{sub 2} from its forbidden transition in the infrared at 1550 cm{sup -1}. From the measurements we derive radiation yields, which we find to be particularly high for the decomposition of hydrogen peroxide; this can be explained by the occurrence of a chemical chain reaction.

  8. Vapor Hydrogen Peroxide as Alternative to Dry Heat Microbial Reduction

    NASA Technical Reports Server (NTRS)

    Cash, Howard A.; Kern, Roger G.; Chung, Shirley Y.; Koukol, Robert C.; Barengoltz, Jack B.

    2006-01-01

    The Jet Propulsion Laboratory, in conjunction with the NASA Planetary Protection Officer, has selected vapor phase hydrogen peroxide (VHP) sterilization process for continued development as a NASA approved sterilization technique for spacecraft subsystems and systems. The goal is to include this technique, with appropriate specification, in NPG8020.12C as a low temperature complementary technique to the dry heat sterilization process. A series of experiments were conducted in vacuum to determine VHP process parameters that provided significant reductions in spore viability while allowing survival of sufficient spores for statistically significant enumeration. With this knowledge of D values, sensible margins can be applied in a planetary protection specification. The outcome of this study provided an optimization of test sterilizer process conditions: VHP concentration, process duration, a process temperature range for which the worst case D value may be imposed, a process humidity range for which the worst case D value may be imposed, and robustness to selected spacecraft material substrates.

  9. Plasma Depolymerization of Chitosan in the Presence of Hydrogen Peroxide

    PubMed Central

    Ma, Fengming; Wang, Zhenyu; Zhao, Haitian; Tian, Shuangqi

    2012-01-01

    The depolymerization of chitosan by plasma in the presence of hydrogen peroxide (H2O2) was investigated. The efficiency of the depolymerization was demonstrated by means of determination of viscosity-average molecular weight and gel permeation chromatography (GPC). The structure of the depolymerized chitosan was characterized by Fourier-transform infrared spectra (FT-IR), ultraviolet spectra (UV) and X-ray diffraction (XRD). The results showed that chitosan can be effectively degradated by plasma in the presence of H2O2. The chemical structure of the depolymerized chitosan was not obviously modified. The combined plasma/H2O2 method is significantly efficient for scale-up manufacturing of low molecular weight chitosan. PMID:22837727

  10. Hydrogen peroxide removal with magnetically responsive Saccharomyces cerevisiae cells.

    PubMed

    Safarik, Ivo; Sabatkova, Zdenka; Safarikova, Mirka

    2008-09-10

    Hydrogen peroxide (HP) is a promising chemical sanitizer for use in the food industry. Its residues have to be decomposed, usually using an enzyme process employing catalase. In order to offer an inexpensive biocatalyst and to simplify subsequent manipulation, we have prepared magnetically responsive alginate beads containing entrapped Saccharomyces cerevisiae cells and magnetite microparticles. Larger beads (2-3 mm in diameter) were prepared by dropping the mixture into calcium chloride solution, while microbeads (the diameter of majority of particles ranged between 50 and 100 microm) were prepared using the water in oil emulsification process. In general, microbeads enabled more efficient HP decomposition. The prepared microparticulate biocatalyst caused efficient decomposition of HP in water solutions (up to 2% concentration), leaving very low residual HP concentration after treatment (below 0.001% under appropriate conditions). The biocatalyst was stable; the same catalytic activity was observed after one month storage at 4 degrees C, and the microbeads could be used at least five times.

  11. Temperature-dependent absorption cross sections for hydrogen peroxide vapor

    NASA Technical Reports Server (NTRS)

    Nicovich, J. M.; Wine, P. H.

    1988-01-01

    Relative absorption cross sections for hydrogen peroxide vapor were measured over the temperature ranges 285-381 K for lambda = 230 nm-295 nm and 300-381 K for lambda = 193 nm-350 nm. The well established 298 K cross sections at 202.6 and 228.8 nm were used as an absolute calibration. A significant temperature dependence was observed at the important tropospheric photolysis wavelengths lambda over 300 nm. Measured cross sections were extrapolated to lower temperatures, using a simple model which attributes the observed temperature dependence to enhanced absorption by molecules possessing one quantum of O-O stretch vibrational excitation. Upper tropospheric photodissociation rates calculated using the extrapolated cross sections are about 25 percent lower than those calculated using currently recommended 298 K cross sections.

  12. Direct synthesis of hydrogen peroxide from plasma-water interactions

    NASA Astrophysics Data System (ADS)

    Liu, Jiandi; He, Bangbang; Chen, Qiang; Li, Junshuai; Xiong, Qing; Yue, Guanghui; Zhang, Xianhui; Yang, Size; Liu, Hai; Liu, Qing Huo

    2016-12-01

    Hydrogen peroxide (H2O2) is usually considered to be an important reagent in green chemistry since water is the only by-product in H2O2 involved oxidation reactions. Early studies show that direct synthesis of H2O2 by plasma-water interactions is possible, while the factors affecting the H2O2 production in this method remain unclear. Herein, we present a study on the H2O2 synthesis by atmospheric pressure plasma-water interactions. The results indicate that the most important factors for the H2O2 production are the processes taking place at the plasma-water interface, including sputtering, electric field induced hydrated ion emission, and evaporation. The H2O2 production rate reaches ~1200 μmol/h when the liquid cathode is purified water or an aqueous solution of NaCl with an initial conductivity of 10500 μS cm‑1.

  13. Direct synthesis of hydrogen peroxide from plasma-water interactions.

    PubMed

    Liu, Jiandi; He, Bangbang; Chen, Qiang; Li, Junshuai; Xiong, Qing; Yue, Guanghui; Zhang, Xianhui; Yang, Size; Liu, Hai; Liu, Qing Huo

    2016-12-05

    Hydrogen peroxide (H2O2) is usually considered to be an important reagent in green chemistry since water is the only by-product in H2O2 involved oxidation reactions. Early studies show that direct synthesis of H2O2 by plasma-water interactions is possible, while the factors affecting the H2O2 production in this method remain unclear. Herein, we present a study on the H2O2 synthesis by atmospheric pressure plasma-water interactions. The results indicate that the most important factors for the H2O2 production are the processes taking place at the plasma-water interface, including sputtering, electric field induced hydrated ion emission, and evaporation. The H2O2 production rate reaches ~1200 μmol/h when the liquid cathode is purified water or an aqueous solution of NaCl with an initial conductivity of 10500 μS cm(-1).

  14. Nanostructure modification to carbon nanowall surface employing hydrogen peroxide solution

    NASA Astrophysics Data System (ADS)

    Shimoeda, Hironao; Kondo, Hiroki; Ishikawa, Kenji; Hiramatsu, Mineo; Sekine, Makoto; Hori, Masaru

    2014-04-01

    Carbon nanowalls (CNWs), which are three-dimensional carbon nanomaterials consisting of stacks of graphene sheets vertically standing on substrates, possess a mazelike architecture containing high-density graphene edges and large-area plane surfaces. A selective morphological modification technique for the surfaces of CNWs after their growth has been developed employing hydrogen peroxide (H2O2) solution. It was found that oxidative radicals in H2O2 solution formed characteristic nanometer-scale asperities on the CNW surface without etching from the top edges. Photoelectron spectra indicate that hydroxyl adsorption and subsequent reactions at the edge and plane of graphene contribute to the selective morphological change on the CNW surface.

  15. Temperature-dependent absorption cross sections for hydrogen peroxide vapor

    NASA Astrophysics Data System (ADS)

    Nicovich, J. M.; Wine, P. H.

    1988-03-01

    Relative absorption cross sections for hydrogen peroxide vapor were measured over the temperature ranges 285-381 K for lambda = 230 nm-295 nm and 300-381 K for lambda = 193 nm-350 nm. The well established 298 K cross sections at 202.6 and 228.8 nm were used as an absolute calibration. A significant temperature dependence was observed at the important tropospheric photolysis wavelengths lambda over 300 nm. Measured cross sections were extrapolated to lower temperatures, using a simple model which attributes the observed temperature dependence to enhanced absorption by molecules possessing one quantum of O-O stretch vibrational excitation. Upper tropospheric photodissociation rates calculated using the extrapolated cross sections are about 25 percent lower than those calculated using currently recommended 298 K cross sections.

  16. Electron transfer properties and hydrogen peroxide electrocatalysis of cytochrome c variants at positions 67 and 80.

    PubMed

    Casalini, Stefano; Battistuzzi, Gianantonio; Borsari, Marco; Bortolotti, Carlo Augusto; Di Rocco, Giulia; Ranieri, Antonio; Sola, Marco

    2010-02-04

    Replacement of the axial Met80 heme ligand in electrode-immobilized cytochrome c with a noncoordinating Ala residue and alteration of the hydrogen bonding network in the region nearby following substitution of Tyr67 were investigated as effectors of the thermodynamics and kinetics of the protein-electrode electron transfer (ET) and the heme-mediated electrocatalytic reduction of H(2)O(2). To this end, the voltammetry of the Met80Ala, Met80Ala/Tyr67His, and Met80Ala/Tyr67Ala variants of yeast iso-1-cytochrome c chemisorbed on carboxyalkanethiol self-assembled monolayers was measured at varying temperature and hydrogen peroxide concentration. The thermodynamic study shows that insertion of His and Ala residues in place of Tyr67 results mainly in differences in protein-solvent interactions at the heme crevice with no relevant effects on the E degrees' values at pH 7, which for single and double variants range from approximately -0.200 to -0.220 V (vs SHE). On the contrary, both double variants show much lower ET rates compared to Met80Ala, most likely as a consequence of a change in the ET pathways. In the present nondenaturing immobilizing conditions, and with hydrogen peroxide concentrations in the micromolar range, the variants catalyze H(2)O(2) reduction at the electrode, whereas wild-type cytochrome c does not. H(2)O(2) electrocatalysis occurs with an efficient mechanism likely involving a fast catalase-like process followed by electrocatalytic reduction of the resulting dioxygen at the electrode. Comparison of Met80Ala/Tyr67His with Met80Ala/Tyr67Ala shows that the presence of a general acid-base residue for H(2)O(2) recognition and binding through H-bonding in the distal heme site is a key requisite for the reductive turnover of this substrate.

  17. Inactivation of possible micromycete food contaminants using the low-temperature plasma and hydrogen peroxide

    NASA Astrophysics Data System (ADS)

    Čeřovský, M.; Khun, J.; Rusová, K.; Scholtz, V.; Soušková, H.

    2013-09-01

    The inhibition effect of hydrogen peroxide aerosol, low-temperature plasma and their combinations has been studied on several micromycetes spores. The low-temperature plasma was generated in corona discharges in the open air apparatus with hydrogen peroxide aerosol. Micromycete spores were inoculated on the surface of agar plates, exposed solely to the hydrogen peroxide aerosol, corona discharge or their combination. After incubation the diameter of inhibition zone was measured. The solely positive corona discharge exhibits no inactivation effect, the solely negative corona discharge and solely hydrogen peroxide aerosol exhibit the inactivation effect, however their combinations exhibit to be much more effective. Low-temperature plasma and hydrogen peroxide aerosol present a possible alternative method of microbial decontamination of food, food packages or other thermolabile materials.

  18. Chemiluminescent nanomicelles for imaging hydrogen peroxide and self-therapy in photodynamic therapy.

    PubMed

    Chen, Rui; Zhang, Luzhong; Gao, Jian; Wu, Wei; Hu, Yong; Jiang, Xiqun

    2011-01-01

    Hydrogen peroxide is a signal molecule of the tumor, and its overproduction makes a higher concentration in tumor tissue compared to normal tissue. Based on the fact that peroxalates can make chemiluminescence with a high efficiency in the presence of hydrogen peroxide, we developed nanomicelles composed of peroxalate ester oligomers and fluorescent dyes, called peroxalate nanomicelles (POMs), which could image hydrogen peroxide with high sensitivity and stability. The potential application of the POMs in photodynamic therapy (PDT) for cancer was also investigated. It was found that the PDT-drug-loaded POMs were sensitive to hydrogen peroxide, and the PDT drug could be stimulated by the chemiluminescence from the reaction between POMs and hydrogen peroxide, which carried on a self-therapy of the tumor without the additional laser light resource.

  19. Hydrogen peroxide-mediated inactivation of two chloroplastic peroxidases, ascorbate peroxidase and 2-cys peroxiredoxin.

    PubMed

    Kitajima, Sakihito

    2008-01-01

    Reactive oxygen species (ROS), such as the superoxide anion and hydrogen peroxide, are generated by the photosystems because photoexcited electrons are often generated in excess of requirements for CO2 fixation and used for reducing molecular oxygen, even under normal environmental conditions. Moreover, ROS generation is increased in chloroplasts if plants are subjected to stresses, such as drought, high salinity and chilling. Chloroplast-localized isoforms of ascorbate peroxidase and possibly peroxiredoxins assume the principal role of scavenging hydrogen peroxide. However, in vitro studies revealed that both types of peroxidases are easily damaged by hydrogen peroxide and lose their catalytic activities. This is one contributing factor for cellular damage that occurs under severe oxidative stress. In this review, I describe mechanisms of hydrogen peroxide-mediated inactivation of these two enzymes and discuss a reason why they became susceptible to damage by hydrogen peroxide.

  20. Localized surface plasmon resonance sensor for simultaneous kinetic determination of peroxyacetic acid and hydrogen peroxide.

    PubMed

    Tashkhourian, Javad; Hormozi-Nezhad, Mohammad Reza; Khodaveisi, Javad; Dashti, Razieh

    2013-01-31

    A new sensor for simultaneous determination of peroxyacetic acid and hydrogen peroxide using silver nanoparticles (Ag-NPs) as a chromogenic reagent is introduced. The silver nanoparticles have the catalytic ability for the decomposition of peroxyacetic acid and hydrogen peroxide; then the decomposition of them induces the degradation of silver nanoparticles. Hence, a remarkable change in the localized surface plasmon resonance absorbance strength could be observed. Spectra-kinetic approach and artificial neural network was applied for the simultaneous determination of peroxyacetic acid and hydrogen peroxide. Linear calibration graphs were obtained in the concentration range of (8.20×10(-5) to 2.00×10(-3) mol L(-1)) for peroxyacetic acid and (2.00×10(-5) to 4.80×10(-3) mol L(-1)) for hydrogen peroxide. The analytical performance of this sensor has been evaluated for the detection of simultaneous determination of peroxyacetic acid and hydrogen peroxide in real samples.

  1. Inactivation of possible micromycete food contaminants using the low-temperature plasma and hydrogen peroxide

    SciTech Connect

    Čeřovský, M.; Khun, J.; Rusová, K.; Scholtz, V.; Soušková, H.

    2013-09-15

    The inhibition effect of hydrogen peroxide aerosol, low-temperature plasma and their combinations has been studied on several micromycetes spores. The low-temperature plasma was generated in corona discharges in the open air apparatus with hydrogen peroxide aerosol. Micromycete spores were inoculated on the surface of agar plates, exposed solely to the hydrogen peroxide aerosol, corona discharge or their combination. After incubation the diameter of inhibition zone was measured. The solely positive corona discharge exhibits no inactivation effect, the solely negative corona discharge and solely hydrogen peroxide aerosol exhibit the inactivation effect, however their combinations exhibit to be much more effective. Low-temperature plasma and hydrogen peroxide aerosol present a possible alternative method of microbial decontamination of food, food packages or other thermolabile materials.

  2. Spatially-resolved intracellular sensing of hydrogen peroxide in living cells

    PubMed Central

    Warren, Emilie A. K.; Netterfield, Tatiana S.; Sarkar, Saheli; Kemp, Melissa L.; Payne, Christine K.

    2015-01-01

    Understanding intracellular redox chemistry requires new tools for the site-specific visualization of intracellular oxidation. We have developed a spatially-resolved intracellular sensor of hydrogen peroxide, HyPer-Tau, for time-resolved imaging in live cells. This sensor consists of a hydrogen peroxide-sensing protein tethered to microtubules. We demonstrate the use of the HyPer-Tau sensor for three applications; dose-dependent response of human cells to exogenous hydrogen peroxide, a model immune response of mouse macrophages to stimulation by bacterial toxin, and a spatially-resolved response to localized delivery of hydrogen peroxide. These results demonstrate that HyPer-Tau can be used as an effective tool for tracking changes in spatially localized intracellular hydrogen peroxide and for future applications in redox signaling. PMID:26585385

  3. Spatially-resolved intracellular sensing of hydrogen peroxide in living cells.

    PubMed

    Warren, Emilie A K; Netterfield, Tatiana S; Sarkar, Saheli; Kemp, Melissa L; Payne, Christine K

    2015-11-20

    Understanding intracellular redox chemistry requires new tools for the site-specific visualization of intracellular oxidation. We have developed a spatially-resolved intracellular sensor of hydrogen peroxide, HyPer-Tau, for time-resolved imaging in live cells. This sensor consists of a hydrogen peroxide-sensing protein tethered to microtubules. We demonstrate the use of the HyPer-Tau sensor for three applications; dose-dependent response of human cells to exogenous hydrogen peroxide, a model immune response of mouse macrophages to stimulation by bacterial toxin, and a spatially-resolved response to localized delivery of hydrogen peroxide. These results demonstrate that HyPer-Tau can be used as an effective tool for tracking changes in spatially localized intracellular hydrogen peroxide and for future applications in redox signaling.

  4. Oxidation of polynuclear aromatic hydrocarbons in water. 4: Ozone combined with hydrogen peroxide

    SciTech Connect

    Beltran, F.J.; Rivas, J.; Ovejero, G.

    1996-03-01

    Three polynuclear aromatic hydrocarbons, fluorene, phenanthrene, and acenaphthene, have been treated in water with ozone combined with hydrogen peroxide. The effect of hydrogen peroxide concentration, pH, and bicarbonate ions has been investigated. The process goes through direct and radical reactions in the case of fluorene and phenanthrene oxidation, while acenaphthene is removed exclusively by direct ozonation. At concentrations of hydrogen peroxide higher than 10{sup {minus}5} M, ozone mass transfer controls the process rate, regardless of pH. In any case, however, the presence of hydrogen peroxide does not improve the oxidation rate compared to ozonation alone due to the importance of the direct reactions. Intermediate compounds identified during oxidation with ozone alone and combined with UV radiation or hydrogen peroxide are similar and justify the high consumption of ozone in these processes.

  5. Effect of hydrogen peroxide and sodium perborate on biomechanical properties of human dentin.

    PubMed

    Chng, Hui Kheng; Palamara, Joseph E A; Messer, Harold H

    2002-02-01

    This study compared the ultimate tensile strength, micropunch shear strength, and microhardness of bleached and unbleached human dentin. Forty-four intact premolars were root canal treated and randomly divided into four groups. Bleaching agents were sealed in pulp chambers, as in clinical use. Group 1 (control) was treated with water, group 2 with 30% hydrogen peroxide, group 3 with sodium perborate mixed with water, and group 4 with sodium perborate mixed with 30% hydrogen peroxide. The teeth were stored in saline at 37 degrees C for 7 days. The teeth were then sectioned and biomechanical tests were carried out on dentin specimens that were obtained from all teeth. Intracoronal bleaching with 30% hydrogen peroxide and sodium perborate used either alone or in combination weakened dentin. Hydrogen peroxide alone tended to be more damaging than sodium perborate used alone or sodium perborate mixed with hydrogen peroxide.

  6. Hydrogen Peroxide, Signaling in Disguise during Metal Phytotoxicity

    PubMed Central

    Cuypers, Ann; Hendrix, Sophie; Amaral dos Reis, Rafaela; De Smet, Stefanie; Deckers, Jana; Gielen, Heidi; Jozefczak, Marijke; Loix, Christophe; Vercampt, Hanne; Vangronsveld, Jaco; Keunen, Els

    2016-01-01

    Plants exposed to excess metals are challenged by an increased generation of reactive oxygen species (ROS) such as superoxide (O2•-), hydrogen peroxide (H2O2) and the hydroxyl radical (•OH). The mechanisms underlying this oxidative challenge are often dependent on metal-specific properties and might play a role in stress perception, signaling and acclimation. Although ROS were initially considered as toxic compounds causing damage to various cellular structures, their role as signaling molecules became a topic of intense research over the last decade. Hydrogen peroxide in particular is important in signaling because of its relatively low toxicity, long lifespan and its ability to cross cellular membranes. The delicate balance between its production and scavenging by a plethora of enzymatic and metabolic antioxidants is crucial in the onset of diverse signaling cascades that finally lead to plant acclimation to metal stress. In this review, our current knowledge on the dual role of ROS in metal-exposed plants is presented. Evidence for a relationship between H2O2 and plant metal tolerance is provided. Furthermore, emphasis is put on recent advances in understanding cellular damage and downstream signaling responses as a result of metal-induced H2O2 production. Finally, special attention is paid to the interaction between H2O2 and other signaling components such as transcription factors, mitogen-activated protein kinases, phytohormones and regulating systems (e.g. microRNAs). These responses potentially underlie metal-induced senescence in plants. Elucidating the signaling network activated during metal stress is a pivotal step to make progress in applied technologies like phytoremediation of polluted soils. PMID:27199999

  7. Development of hydrogen peroxide technique for bioburden reduction

    NASA Astrophysics Data System (ADS)

    Rohatgi, N.; Schwartz, L.; Stabekis, P.; Barengoltz, J.

    In order to meet the National Aeronautics and Space Administration (NASA) Planetary Protection microbial reduction requirements for Mars in-situ life detection and sample return missions, entire planetary spacecraft (including planetary entry probes and planetary landing capsules) may have to be exposed to a qualified sterilization process. Presently, dry heat is the only NASA approved sterilization technique available for spacecraft application. However, with the increasing use of various man-made materials, highly sophisticated electronic circuit boards, and sensors in a modern spacecraft, compatibility issues may render this process unacceptable to design engineers and thus impractical to achieve terminal sterilization of the entire spacecraft. An alternative vapor phase hydrogen peroxide sterilization process, which is currently used in various industries, has been selected for further development. Strategic Technology Enterprises, Incorporated (STE), a subsidiary of STERIS Corporation, under a contract from the Jet Propulsion Laboratory (JPL) is developing systems and methodologies to decontaminate spacecraft using vaporized hydrogen peroxide (VHP) technology. The VHP technology provides an effective, rapid and low temperature means for inactivation of spores, mycobacteria, fungi, viruses and other microorganisms. The VHP application is a dry process affording excellent material compatibility with many of the components found in spacecraft such as polymers, paints and electronic systems. Furthermore, the VHP process has innocuous residuals as it decomposes to water vapor and oxygen. This paper will discuss the approach that is being used to develop this technique and will present lethality data that have been collected to establish deep vacuum VHP sterilization cycles. In addition, the application of this technique to meet planetary protection requirements will be addressed.

  8. Depletion Rate of Hydrogen Peroxide from Sodium Perborate Bleaching Agent.

    PubMed

    Tran, Liliann; Orth, Rebecca; Parashos, Peter; Tao, Ying; Tee, Calvin W J; Thomas, Vineet Thenalil; Towers, Georgina; Truong, Diem Thuy; Vinen, Cynthia; Reynolds, Eric C

    2017-03-01

    Internal bleaching of discolored teeth uses sodium perborate reacting with water to form the active agent, hydrogen peroxide (H2O2). Sodium perborate is replaced at varying time intervals depending on clinician preference and until esthetically acceptable results are achieved, but this is done without scientific basis. This study measured the depletion rate of hydrogen peroxide from sodium perborate as a bleaching agent. Two sodium perborate bleaching products (Odontobleach [Australian Dental Manufacturing, Kenmore Hills, Queensland, Australia] and Endosure Perborate Micro [Dentalife, Ringwood, Victoria, Australia]) and distilled deionized water mixtures at ratios of 25 μg/mL, 50 μg/mL, and 100 μg/mL were placed into sealed microtubes and incubated at 37°C. H2O2 concentrations were measured at 23 time points over 4 weeks. Quantification of H2O2 concentrations was obtained using a ferrothiocyanate oxidation reduction reaction followed by spectrophotometry readings. The H2O2 concentration rapidly peaked within 27 hours and reached a plateau by about 3 days (75 hours). Low levels of H2O2 were evident beyond 3 days and for at least 28 days. No significant differences were found between the 2 sodium perborate products. There was also no significant difference in the depletion rate between the different ratios. Based on the chemistry of H2O2 depletion, the minimum replacement interval for the bleaching agent is 3 days. Frequent replacements of the perborate clinically may be unnecessary because of the continued presence of low H2O2 levels for at least 28 days. Although these data cannot be extrapolated to the clinical situation, they set a baseline for further studies to address the many clinical variables influencing internal bleaching. Copyright © 2016 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

  9. Formation of C–C Bonds via Iridium-Catalyzed Hydrogenation and Transfer Hydrogenation

    PubMed Central

    Bower, John F.; Krische, Michael J.

    2011-01-01

    The formation of C–C bonds via catalytic hydrogenation and transfer hydrogenation enables carbonyl and imine addition in the absence of stoichiometric organometallic reagents. In this review, iridium-catalyzed C–C bond-forming hydrogenations and transfer hydrogenations are surveyed. These processes encompass selective, atom-economic methods for the vinylation and allylation of carbonyl compounds and imines. Notably, under transfer hydrogenation conditions, alcohol dehydrogenation drives reductive generation of organoiridium nucleophiles, enabling carbonyl addition from the aldehyde or alcohol oxidation level. In the latter case, hydrogen exchange between alcohols and π-unsaturated reactants generates electrophile–nucleophile pairs en route to products of hydro-hydroxyalkylation, representing a direct method for the functionalization of carbinol C–H bonds. PMID:21822399

  10. Oxidation of benzo(a)pyrene-7,8-diol by methemoglobin and hydrogen peroxide

    SciTech Connect

    Catalano, C.E.; Ortiz, de Montellano, P.R.

    1986-05-01

    Methemoglobin catalyzes the hydrogen peroxide dependent oxidation of styrene to styrene oxide. An alkylperoxy radical formed from the combination of molecular oxygen with an amino acid radical at the protein surface has been proposed as the actual oxidant. This model predicts that access to the heme crevice is not a requirement for oxidation. The oxidation of benzo(a)pyrene-7.8-dihydro-diol, a substrate whose steric bulk makes access into the heme crevice unlikely, has been examined to further test this hypothesis. Anti-trans-benzo(a)pyrene-7,8,9,10-tetrol is isolated from the incubation of B(a)P-diol in the presence of methemoglobin and H/sub 2/O/sub 2/. The exclusive formation of this tetrol supports a peroxidative epoxidation mechanism analogous to that for lipid peroxy radical oxidation of the title compound. The oxidation of conjugated fatty acids by the methemoglobin/H/sub 2/O/sub 2/ system further supports the hypothesis that oxidation of compounds occurs at protein surface and not in the heme crevice as previously suspected.

  11. Overoxidation of chloroplast 2-Cys peroxiredoxins: balancing toxic and signaling activities of hydrogen peroxide.

    PubMed

    Puerto-Galán, Leonor; Pérez-Ruiz, Juan M; Ferrández, Julia; Cano, Beatriz; Naranjo, Belén; Nájera, Victoria A; González, Maricruz; Lindahl, Anna M; Cejudo, Francisco J

    2013-01-01

    Photosynthesis, the primary source of biomass and oxygen into the biosphere, involves the transport of electrons in the presence of oxygen and, therefore, chloroplasts constitute an important source of reactive oxygen species, including hydrogen peroxide. If accumulated at high level, hydrogen peroxide may exert a toxic effect; however, it is as well an important second messenger. In order to balance the toxic and signaling activities of hydrogen peroxide its level has to be tightly controlled. To this end, chloroplasts are equipped with different antioxidant systems such as 2-Cys peroxiredoxins (2-Cys Prxs), thiol-based peroxidases able to reduce hydrogen and organic peroxides. At high peroxide concentrations the peroxidase function of 2-Cys Prxs may become inactivated through a process of overoxidation. This inactivation has been proposed to explain the signaling function of hydrogen peroxide in eukaryotes, whereas in prokaryotes, the 2-Cys Prxs of which were considered to be insensitive to overoxidation, the signaling activity of hydrogen peroxide is less relevant. Here we discuss the current knowledge about the mechanisms controlling 2-Cys Prx overoxidation in chloroplasts, organelles with an important signaling function in plants. Given the prokaryotic origin of chloroplasts, we discuss the occurrence of 2-Cys Prx overoxidation in cyanobacteria with the aim of identifying similarities between chloroplasts and their ancestors regarding their response to hydrogen peroxide.

  12. Measurement of hydrogen peroxide in an advanced oxidation process using an automated biosensor.

    PubMed

    Modrzejewska, B; Guwy, A J; Dinsdale, R; Hawkes, D L

    2007-01-01

    A hydrogen peroxide biosensor was used to monitor hydrogen peroxide concentrations in a UV/hydrogen peroxide immobilised Fenton advanced oxidation process (AOP). The biosensor is based on gas phase monitoring and thus is more resistant to fouling from the liquid phase constituents of industrial processes. The biosensor is supplied with catalase continually, therefore overcoming any problems with enzyme degradation, which would occur in an immobilised enzyme biosensor. The biosensors response was linear within the experimental range 30-400mg H(2)O(2)l(-1) with a R(2) correlation of 0.99. The hydrogen peroxide monitor was used to monitor residual peroxide in an AOP, operated with a step overload of hydrogen peroxide, with correlation factors of 0.96-0.99 compared to offline hydrogen peroxide determinations by UV spectroscopy. Sparging the sample with nitrogen was found to be effective in reducing the interference from dissolved gases produced with the AOP itself. It is proposed that this biosensor could be used to improve the effectiveness of AOPs via hydrogen peroxide control.

  13. Hydrogen cycling of niobium and vanadium catalyzed nanostructured magnesium.

    PubMed

    Schimmel, H Gijs; Huot, Jacques; Chapon, Laurent C; Tichelaar, Frans D; Mulder, Fokko M

    2005-10-19

    The reaction of hydrogen gas with magnesium metal, which is important for hydrogen storage purposes, is enhanced significantly by the addition of catalysts such as Nb and V and by using nanostructured powders. In situ neutron diffraction on MgNb(0.05) and MgV(0.05) powders give a detailed insight on the magnesium and catalyst phases that exist during the various stages of hydrogen cycling. During the early stage of hydriding (and deuteriding), a MgH(1< x < 2) phase is observed, which does not occur in bulk MgH(2) and, thus, appears characteristic for the small particles. The abundant H vacancies will cause this phase to have a much larger hydrogen diffusion coefficient, partly explaining the enhanced kinetics of nanostructured magnesium. It is shown that under relevant experimental conditions, the niobium catalyst is present as NbH(1). Second, a hitherto unknown Mg-Nb perovskite phase could be identified that has to result from mechanical alloying of Nb and the MgO layer of the particles. Vanadium is not visible in the diffraction patterns, but electron micrographs show that the V particle size becomes very small, 2-20 nm. Nanostructuring and catalyzing the Mg enhance the adsorption speed that much that now temperature variations effectively limit the absorption speed and not, as for bulk, the slow kinetics through bulk MgH(2) layers.

  14. Alkylsilyl Peroxides as Alkylating Agents in the Copper-Catalyzed Selective Mono-N-Alkylation of Primary Amides and Arylamines.

    PubMed

    Sakamoto, Ryu; Sakurai, Shunya; Maruoka, Keiji

    2017-07-06

    The copper-catalyzed selective mono-N-alkylation of primary amides or arylamines using alkylsilyl peroxides as alkylating agents is reported. The reaction proceeds under mild reaction conditions and exhibits a broad substrate scope with respect to the alkylsilyl peroxides, as well as to the primary amides and arylamines. Mechanistic studies suggest that the present reaction should proceed through a free-radical process that includes alkyl radicals generated from the alkylsilyl peroxides. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  15. Vascular adhesion protein-1 enhances neutrophil infiltration by generation of hydrogen peroxide in renal ischemia/reperfusion injury.

    PubMed

    Tanaka, Shinji; Tanaka, Tetsuhiro; Kawakami, Takahisa; Takano, Hideki; Sugahara, Mai; Saito, Hisako; Higashijima, Yoshiki; Yamaguchi, Junna; Inagi, Reiko; Nangaku, Masaomi

    2017-07-01

    Vascular adhesion protein-1 (VAP-1) is a unique molecule since it acts as an adhesion molecule as well as an ectoenzyme catalyzing oxidative deamination of primary amines and generates hydrogen peroxide in the extracellular space. While VAP-1 is implicated in various inflammatory diseases, its role in acute kidney injury is less characterized. Here we studied VAP-1 expression in the kidney and the effect of its inhibition in a rat model of renal ischemia/reperfusion injury. VAP-1 was predominantly expressed in pericytes, which released enzymatically active enzyme. In vivo, a specific VAP-1 inhibitor, RTU-1096, significantly ameliorated rat renal ischemia/reperfusion injury and decreased neutrophil infiltration measured 12 hours after injury without altering macrophage or T lymphocyte populations. The protective effect of VAP-1 inhibition was lost in neutrophil-depleted rats, suggesting its inhibition ameliorated renal ischemia/reperfusion injury by suppressing neutrophil infiltration. To investigate whether hydrogen peroxide generated by VAP-1 enzyme reaction enhances neutrophil infiltration, we conducted an under-agarose migration assay with purified human neutrophils. Recombinant human VAP-1 significantly induced neutrophil migration, which was almost completely inhibited by RTU-1096 or catalase. Thus, VAP-1 plays a critical role in the pathophysiology of renal ischemia/reperfusion injury by enhancement of neutrophil infiltration generating a local hydrogen peroxide gradient. Hence, VAP-1 inhibition may be a novel therapy in ischemic acute kidney injury. Copyright © 2017 International Society of Nephrology. Published by Elsevier Inc. All rights reserved.

  16. Fabrication of a facile electrochemical biosensor for hydrogen peroxide using efficient catalysis of hemoglobin on the porous Pd@Fe3O4-MWCNT nanocomposite.

    PubMed

    Baghayeri, Mehdi; Veisi, Hojat

    2015-12-15

    In this work, a sensitive amperometric biosensor for hydrogen peroxide based on synergetic catalysis of hemoglobin and porous Pd@Fe3O4-MWCNT nanocomposite has been constructed. With attention to the utilities of large surface area and outstanding catalytic performance, Pd@Fe3O4-MWCNT nanocomposite was employed as the nano-stabilizer for the immobilization of hemoglobin (Hb). The immobilized Hb on the surface of nanocomposite as an electrochemical biosensor efficiently catalyzed the reduction of hydrogen peroxide, amplified the electrochemical signal and enhanced the sensitivity. Results of voltammetry and electrochemical impedance examinations showed that the nanocomposite could enhance the electron conductivity and provide more sites for the immobilization of Hb. A linear response from 0.2-500 µM with detection limit of 0.063 µM for hydrogen peroxide was achieved. The apparent Michaelis-Menten constant Kapp(M) value was 21 µM. Thus, the nanocomposite could be applied for fabrication of a third generation biosensor for hydrogen peroxide with high sensitivity, selectivity and low detection limit. The excellent performance of the biosensor indicated its promising prospect as a valuable tool in simple and fast hydrogen peroxide detection in environmental and clinical applications.

  17. Application of crude extract of kohlrabi (Brassica oleracea gongylodes) as a rich source of peroxidase in the spectrofluorometric determination of hydrogen peroxide in honey samples.

    PubMed

    Manzoori, Jamshid L; Amjadi, Mohammad; Orooji, Maghsood

    2006-09-01

    Crude extract of kohlrabi (Brassica oleracea gongylodes) was prepared by a simple procedure and its enzymatic activity and total protein concentration were determined. It was found that this crude extract is a rich source of peroxidase (POx) and has high specific activity. Cross-linked polyvinylpyrrolidone was used as a stabilizer in the preparation of the crude extract. The POx activity of kohlrabi crude extract did not vary for at least 2 months when deoxygenated and stored at 4 degrees C. This extract was applied for the spectrofluorometric determination of hydrogen peroxide using homovanillic acid as a fluorogenic substrate. POx catalyzes the hydrogen peroxide oxidation of homovanillic acid to produce a dimer which shows strong fluorescence at 420 nm with excitation at 312 nm. In the optimum conditions, the calibration graph for hydrogen peroxide was linear up to 190 ng mL(-1), with a detection limit of 4.4 ng mL(-1). The relative standard deviation (RSD) was 1.48% for 50 ng mL(-1) hydrogen peroxide. The proposed method was successfully applied to the determination of hydrogen peroxide in honey. The concentration-time profile of H2O2 produced upon dilution of honey was studied and H2O2 contents of some different honeys from various areas of Iran were determined.

  18. Evaluation of Extraradicular Diffusion of Hydrogen Peroxide during Intracoronal Bleaching Using Different Bleaching Agents.

    PubMed

    Rokaya, Mohammad E; Beshr, Khaled; Hashem Mahram, Abeer; Samir Pedir, Samah; Baroudi, Kusai

    2015-01-01

    Objectives. Extra radicular diffusion of hydrogen peroxide associated with intracoronal teeth bleaching was evaluated. Methods. 108 intact single rooted extracted mandibular first premolars teeth were selected. The teeth were instrumented with WaveOne system and obturated with gutta percha and divided into four groups (n = 27) according to the bleaching materials used. Each main group was divided into three subgroups (n = 9) according to the time of extra radicular hydrogen peroxide diffusion measurements at 1, 7, and 14 days: group 1 (35% hydrogen peroxide), group 2 (35% carbamide peroxide), group 3 (sodium perborate-30% hydrogen peroxide mixture), and group 4 (sodium perborate-water mixture). Four cemental dentinal defects were prepared just below the CEJ on each root surface. The amount of hydrogen peroxide that leached out was evaluated after 1, 7, and 14 days by spectrophotometer analysis. The results were analyzed using the ANOVA and Tukey's test. Results. Group 1 showed highest extra radicular diffusion, followed by group 3 and group 2, while group 4 showed the lowest mean extra radicular diffusion. Conclusion. Carbamide peroxide and sodium perborate-water mixture are the most suitable bleaching materials used for internal bleaching due to their low extra radicular diffusion of hydrogen peroxide.

  19. Evaluation of Extraradicular Diffusion of Hydrogen Peroxide during Intracoronal Bleaching Using Different Bleaching Agents

    PubMed Central

    Rokaya, Mohammad E.; Beshr, Khaled; Hashem Mahram, Abeer; Samir Pedir, Samah; Baroudi, Kusai

    2015-01-01

    Objectives. Extra radicular diffusion of hydrogen peroxide associated with intracoronal teeth bleaching was evaluated. Methods. 108 intact single rooted extracted mandibular first premolars teeth were selected. The teeth were instrumented with WaveOne system and obturated with gutta percha and divided into four groups (n = 27) according to the bleaching materials used. Each main group was divided into three subgroups (n = 9) according to the time of extra radicular hydrogen peroxide diffusion measurements at 1, 7, and 14 days: group 1 (35% hydrogen peroxide), group 2 (35% carbamide peroxide), group 3 (sodium perborate-30% hydrogen peroxide mixture), and group 4 (sodium perborate-water mixture). Four cemental dentinal defects were prepared just below the CEJ on each root surface. The amount of hydrogen peroxide that leached out was evaluated after 1, 7, and 14 days by spectrophotometer analysis. The results were analyzed using the ANOVA and Tukey's test. Results. Group 1 showed highest extra radicular diffusion, followed by group 3 and group 2, while group 4 showed the lowest mean extra radicular diffusion. Conclusion. Carbamide peroxide and sodium perborate-water mixture are the most suitable bleaching materials used for internal bleaching due to their low extra radicular diffusion of hydrogen peroxide. PMID:26257782

  20. Catalase activity of cytochrome C oxidase assayed with hydrogen peroxide-sensitive electrode microsensor.

    PubMed

    Bolshakov, I A; Vygodina, T V; Gennis, R; Karyakin, A A; Konstantinov, A A

    2010-11-01

    An iron-hexacyanide-covered microelectrode sensor has been used to continuously monitor the kinetics of hydrogen peroxide decomposition catalyzed by oxidized cytochrome oxidase. At cytochrome oxidase concentration ~1 µM, the catalase activity behaves as a first order process with respect to peroxide at concentrations up to ~300-400 µM and is fully blocked by heat inactivation of the enzyme. The catalase (or, rather, pseudocatalase) activity of bovine cytochrome oxidase is characterized by a second order rate constant of ~2·10(2) M(-1)·sec(-1) at pH 7.0 and room temperature, which, when divided by the number of H2O2 molecules disappearing in one catalytic turnover (between 2 and 3), agrees reasonably well with the second order rate constant for H2O2-dependent conversion of the oxidase intermediate F(I)-607 to F(II)-580. Accordingly, the catalase activity of bovine oxidase may be explained by H2O2 procession in the oxygen-reducing center of the enzyme yielding superoxide radicals. Much higher specific rates of H2O2 decomposition are observed with preparations of the bacterial cytochrome c oxidase from Rhodobacter sphaeroides. The observed second order rate constants (up to ~3000 M(-1)·sec(-1)) exceed the rate constant of peroxide binding with the oxygen-reducing center of the oxidized enzyme (~500 M(-1)·sec(-1)) several-fold and therefore cannot be explained by catalytic reaction in the a(3)/Cu(B) site of the enzyme. It is proposed that in the bacterial oxidase, H2O2 can be decomposed by reacting with the adventitious transition metal ions bound by the polyhistidine-tag present in the enzyme, or by virtue of reaction with the tightly-bound Mn2+, which in the bacterial enzyme substitutes for Mg2+ present in the mitochondrial oxidase.

  1. Peroxide-Free Pd(II)-Catalyzed Ortho Aroylation and Ortho Halogenation of Directing Arenes.

    PubMed

    Santra, Sourav Kumar; Banerjee, Arghya; Mohanta, Prakash Ranjan; Patel, Bhisma K

    2016-07-15

    A Pd(II)-catalyzed peroxide-free ortho aroylation of directing arenes has been developed via cross dehydrogenative coupling (CDC) in the presence of the terminal oxidant Cu(OAc)2·H2O. Ortho aroylation of directing arenes proceeds via decarbonylation of the in situ generated phenyl glyoxal, which is obtained from 2-acetoxyacetophenone in the presence of the oxidant Cu(OAc)2·H2O. However, changing the oxidant to CuX2 (X = Cl, Br) provided exclusive di-ortho-halogenated 2-arylbenzothiazoles. During the halogenation, CuX2 served the dual role of a halogen source as well as a co-oxidant.

  2. Results Of Copper Catalyzed Peroxide Oxidation (CCPO) Of Tank 48H Simulants

    SciTech Connect

    Peters, T. B.; Pareizs, J. M.; Newell, J. D.; Fondeur, F. F.; Nash, C. A.; White, T. L.; Fink, S. D.

    2012-12-13

    Savannah River National Laboratory (SRNL) performed a series of laboratory-scale experiments that examined copper-catalyzed hydrogen peroxide (H{sub 2}O{sub 2}) aided destruction of organic components, most notably tetraphenylborate (TPB), in Tank 48H simulant slurries. The experiments were designed with an expectation of conducting the process within existing vessels of Building 241-96H with minimal modifications to the existing equipment. Results of the experiments indicate that TPB destruction levels exceeding 99.9% are achievable, dependent on the reaction conditions. A lower reaction pH provides faster reaction rates (pH 7 > pH 9 > pH 11); however, pH 9 reactions provide the least quantity of organic residual compounds within the limits of species analyzed. Higher temperatures lead to faster reaction rates and smaller quantities of organic residual compounds. A processing temperature of 50°C as part of an overall set of conditions appears to provide a viable TPB destruction time on the order of 4 days. Higher concentrations of the copper catalyst provide faster reaction rates, but the highest copper concentration (500 mg/L) also resulted in the second highest quantity of organic residual compounds. The data in this report suggests 100-250 mg/L as a minimum. Faster rates of H{sub 2}O{sub 2} addition lead to faster reaction rates and lower quantities of organic residual compounds. An addition rate of 0.4 mL/hour, scaled to the full vessel, is suggested for the process. SRNL recommends that for pH adjustment, an acid addition rate 42 mL/hour, scaled to the full vessel, is used. This is the same addition rate used in the testing. Even though the TPB and phenylborates can be destroyed in a relative short time period, the residual organics will take longer to degrade to <10 mg/L. Low level leaching on titanium occurred, however, the typical concentrations of released titanium are very low (~40 mg/L or less). A small amount of leaching under these conditions is not

  3. Effect of carbamide peroxide and hydrogen peroxide on enamel surface: an in vitro study.

    PubMed

    Abouassi, Thaer; Wolkewitz, Martin; Hahn, Petra

    2011-10-01

    The aim of the study was to investigate changes in the micromorphologyl and microhardness of the enamel surface after bleaching with two different concentrations of hydrogen peroxide (HP) and carbamide peroxide (CP). Bovine enamel samples were embedded in resin blocks, and polished. Specimens in the experimental groups (n = 10) were treated with bleaching gels containing 10% CP, 35% CP, 3.6% HP, and 10% HP, respectively, for 2 h every second day over a period of 2 weeks. The gels had the identical composition and pH and differed only in their HP or CP content. The roughness and morphology of the enamel surface were analyzed using laser profilometry and SEM. Microhardness was measured using a Knoop hardness tester. The data were evaluated statistically. Specimens in the 10% HP group showed significantly higher roughness after bleaching compared to the control group (ΔRa, p = 0.01). Bleaching with 35% CP showed only a tendency to increase roughness (ΔRa, p = 0.06). Application of 10% CP or 3.6% HP had no significant influence on Ra. Enamel microhardness was significantly higher after application of 10% HP compared to the control (ΔMic = 8 KHN, p = 0.0002) and 35% CP (ΔMic = 20KHN, p = 0.01) groups. In summary, application of CP and HP showed only small quantitative and qualitative differences. In addition, the influence of bleaching procedure on the morphology and hardness of the enamel surface depended on the concentration of the active ingredients.

  4. Energy Efficient Catalytic Activation of Hydrogen peroxide for Green Chemical Processes: Final Report

    SciTech Connect

    Collins, Terrence J.; Horwitz, Colin

    2004-11-12

    A new, highly energy efficient approach for using catalytic oxidation chemistry in multiple fields of technology has been pursued. The new catalysts, called TAML® activators, catalyze the reactions of hydrogen peroxide and other oxidants for the exceptionally rapid decontamination of noninfectious simulants (B. atrophaeus) of anthrax spores, for the energy efficient decontamination of thiophosphate pesticides, for the facile, low temperature removal of color and organochlorines from pulp and paper mill effluent, for the bleaching of dyes from textile mill effluents, and for the removal of recalcitrant dibenzothiophene compounds from diesel and gasoline fuels. Highlights include the following: 1) A 7-log kill of Bacillus atrophaeus spores has been achieved unambiguously in water under ambient conditions within 15 minutes. 2) The rapid total degradation under ambient conditions of four thiophosphate pesticides and phosphonate degradation intermediates has been achieved on treatment with TAML/peroxide, opening up potential applications of the decontamination system for phosphonate structured chemical warfare agents, for inexpensive, easy to perform degradation of stored and aged pesticide stocks (especially in Africa and Asia), for remediation of polluted sites and water bodies, and for the destruction of chemical warfare agent stockpiles. 3) A mill trial conducted in a Pennsylvanian bleached kraft pulp mill has established that TAML catalyst injected into an alkaline peroxide bleach tower can significantly lower color from the effluent stream promising a new, more cost effective, energy-saving approach for color remediation adding further evidence of the value and diverse engineering capacity of the approach to other field trials conducted on effluent streams as they exit the bleach plant. 4) Dibenzothiophenes (DBTs), including 4,6-dimethyldibenzothiophene, the most recalcitrant sulfur compounds in diesel and gasoline, can be completely removed from model gasoline

  5. Recent advances in hydrogen peroxide imaging for biological applications.

    PubMed

    Guo, Hengchang; Aleyasin, Hossein; Dickinson, Bryan C; Haskew-Layton, Renée E; Ratan, Rajiv R

    2014-01-01

    Mounting evidence supports the role of hydrogen peroxide (H2O2) in physiological signaling as well as pathological conditions. However, the subtleties of peroxide-mediated signaling are not well understood, in part because the generation, degradation, and diffusion of H2O2 are highly volatile within different cellular compartments. Therefore, the direct measurement of H2O2 in living specimens is critically important. Fluorescent probes that can detect small changes in H2O2 levels within relevant cellular compartments are important tools to study the spatial dynamics of H2O2. To achieve temporal resolution, the probes must also be photostable enough to allow multiple readings over time without loss of signal. Traditional fluorescent redox sensitive probes that have been commonly used for the detection of H2O2 tend to react with a wide variety of reactive oxygen species (ROS) and often suffer from photostablilty issues. Recently, new classes of H2O2 probes have been designed to detect H2O2 with high selectivity. Advances in H2O2 measurement have enabled biomedical scientists to study H2O2 biology at a level of precision previously unachievable. In addition, new imaging techniques such as two-photon microscopy (TPM) have been employed for H2O2 detection, which permit real-time measurements of H2O2 in vivo. This review focuses on recent advances in H2O2 probe development and optical imaging technologies that have been developed for biomedical applications.

  6. Application of mid-infrared spectroscopy: measuring hydrogen peroxide concentrations in bleaching baths.

    PubMed

    Voraberger, Hannes; Ribitsch, Volker; Janotta, Markus; Mizaikoff, Boris

    2003-05-01

    The presented work applies mid-infrared attenuated total reflection (ATR) spectroscopy to the measurment of hydrogen peroxide in aqueous matrices. The performance of different ATR crystals mounted in flow cells was investigated in the presence of aqueous hydrogen peroxide solutions. Quantitative determination has been achieved by evaluation of specific OH stretching and deformation vibrations with linear correlation between peak areas or peak heights and hydrogen peroxide concentration in the range of 1-10% (weight in water). Important aspects such as chemical stability of the waveguide material and influences of pH and ionic strength on the performance are discussed. Feasibility for the investigation of real world samples is demonstrated by measuring industrial bleaching solutions with known concentrations of hydrogen peroxide fitting well with calibration graphs established with neat hydrogen peroxide solutions. The presented sensor system is capable of determining hydrogen peroxide within complex matrices and clearly corroborates the potential of providing an in situ measurement concept for on-line hydrogen peroxide detection.

  7. Hydrogen peroxide sensing and signaling by protein kinases in the cardiovascular system.

    PubMed

    Burgoyne, Joseph R; Oka, Shin-ichi; Ale-Agha, Niloofar; Eaton, Philip

    2013-03-20

    Oxidants were once principally considered perpetrators of injury and disease. However, this has become an antiquated view, with cumulative evidence showing that the oxidant hydrogen peroxide serves as a signaling molecule. Hydrogen peroxide carries vital information about the redox state of the cell and is crucial for homeostatic regulation during health and adaptation to stress. In this review, we examine the contemporary concepts for how hydrogen peroxide is sensed and transduced into a biological response by introducing post-translational oxidative modifications on select proteins. Oxidant sensing and signaling by kinases are of particular importance as they integrate oxidant signals into phospho-regulated pathways. We focus on CAMKII, PKA, and PKG, kinases whose redox regulation has notable impact on cardiovascular function. In addition, we examine the mechanism for regulating intracellular hydrogen peroxide, considering the net concentrations that may accumulate. The effects of endogenously generated oxidants are often modeled by applying exogenous hydrogen peroxide to cells or tissues. Here we consider whether model systems exposed to exogenous hydrogen peroxide have relevance to systems where the oxidant is generated endogenously, and if so, what concentration can be justified in terms of relevance to health and disease. Improving our understanding of hydrogen peroxide signaling and the sensor proteins that it can modify will help us develop new strategies to regulate intracellular signaling to prevent disease.

  8. PyBidine-NiCl2-Catalyzed Asymmetric Addition of Alcohols and Peroxides to Isatin-Derived Ketimines.

    PubMed

    Arai, Takayoshi; Tsuchiya, Kento; Matsumura, Eri

    2015-05-15

    An (S,S)-diphenyldiamine-derived bis(imidazolidine)pyridine (PyBidine)-NiCl2 complex catalyzed the asymmetric addition of methanol and peroxides to isatin-derived N-Boc-imines to form chiral quaternary N,O-acetals at the C3 position of the resulting oxiindoles in up to 99% yield with 94% ee.

  9. Mucolysis by ascorbic acid and hydrogen peroxide on compact mucin secreted in pseudomyxoma peritonei.

    PubMed

    Pillai, Krishna; Akhter, Javed; Chua, Terence C; Morris, David L

    2012-05-15

    This study examines the potential efficacy of hydrogen peroxide and ascorbic acid in the dissolution of mucinous ascites from pseudomyxoma peritonei. The mucolytic action of both ascorbic acid (0%-0.2%) and hydrogen peroxide (0%-3%) are investigated as single agent on mucin samples derived from patient. This was followed by examining the joint action of ascorbic acid (0.2%) and hydrogen peroxide (0%-3.0%) on mucin. To lower the concentration of hydrogen peroxide in the mixture, the action of equal concentration of ascorbic acid/hydrogen peroxide ranging from 0%-0.3% are then examined. Finally, the pH (4.5-7.0) effect on mucolytic properties of equal concentration (0.2%) of ascorbic acid/hydrogen peroxide was studied. At the concentrations examined (0%-0.2%), ascorbic acid showed highest mucolytic activity at 0.2%. Similarly, hydrogen peroxide as a single agent (0%-3.0%) showed highest mucolytic activity at 3.0%. The mucolytic action of hydrogen peroxide (0%-3.0%) containing 0.2% ascorbic acid demonstrated synergistic effects. At equal concentration of the two agents, ranging from 0%-0.5%, maximal mucolytic action was observed at 0.2%. The mucolytic property of the final mixture (0.2% ascorbic acid/0.2% hydrogen peroxide) was pH-dependent and showed maximal degradation at pH 4.5 and declined as it reached towards neutral pH. The current study introduces the potential applicability of a formulation that holds promise as a mucolytic agent in patients with mucinous ascites from pseudomyxoma peritonei. Copyright © 2012 Elsevier Inc. All rights reserved.

  10. Converting Chemical Energy to Electricity through a Three-Jaw Mini-Generator Driven by the Decomposition of Hydrogen Peroxide.

    PubMed

    Xiao, Meng; Wang, Lei; Ji, Fanqin; Shi, Feng

    2016-05-11

    Energy conversion from a mechanical form to electricity is one of the most important research advancements to come from the horizontal locomotion of small objects. Until now, the Marangoni effect has been the only propulsion method to produce the horizontal locomotion to induce an electromotive force, which is limited to a short duration because of the specific property of surfactants. To solve this issue, in this article we utilized the decomposition of hydrogen peroxide to provide the propulsion for a sustainable energy conversion from a mechanical form to electricity. We fabricated a mini-generator consisting of three parts: a superhydrophobic rotator with three jaws, three motors to produce a jet of oxygen bubbles to propel the rotation of the rotator, and three magnets integrated into the upper surface of the rotator to produce the magnet flux. Once the mini-generator was placed on the solution surface, the motor catalyzed the decomposition of hydrogen peroxide. This generated a large amount of oxygen bubbles that caused the generator and integrated magnets to rotate at the air/water interface. Thus, the magnets passed under the coil area and induced a change in the magnet flux, thus generating electromotive forces. We also investigated experimental factors, that is, the concentration of hydrogen peroxide and the turns of the solenoid coil, and found that the mini-generator gave the highest output in a hydrogen peroxide solution with a concentration of 10 wt % and under a coil with 9000 turns. Through combining the stable superhydrophobicity and catalyst, we realized electricity generation for a long duration, which could last for 26 000 s after adding H2O2 only once. We believe this work provides a simple process for the development of horizontal motion and provides a new path for energy reutilization.

  11. Development of biological and nonbiological explanations for the Viking label release data. [hydrogen peroxide theory

    NASA Technical Reports Server (NTRS)

    1980-01-01

    The plausibility that hydrogen peroxide, widely distributed within the Mars surface material, was responsible for the evocative response obtained by the Viking Labeled Release (LR) experiment on Mars was investigated. Although a mixture of gamma Fe2O3 and silica sand stimulated the LR nutrient reaction with hydrogen peroxide and reduced the rate of hydrogen decomposition under various storage conditions, the Mars analog soil prepared by the Viking Inorganic Analysis Team to match the Mars analytical data does not cause such effects. Nor is adequate resistance to UV irradiation shown. On the basis of the results and consideration presented while the hydrogen peroxide theory remains the most, if not only, attractive chemical explanation of the LR data, it remains unconvincing on critical points. Until problems concerning the formation and stabilization of hydrogen peroxide on the surface of Mars can be overcome, adhere to the scientific evidence requires serious consideration of the biological theory.

  12. Alkyl peroxides reveal the ring opening mechanism of verdoheme catalyzed by heme oxygenase.

    PubMed

    Matsui, Toshitaka; Omori, Kohei; Jin, Hiromichi; Ikeda-Saito, Masao

    2008-04-02

    Heme oxygenase (HO) catalyzes heme catabolism through three successive oxygenation steps where the substrate heme itself activates O2. Although a rate-determining step of the HO catalysis is considered as third oxygenation, the verdoheme degradation mechanism has been the least understood in the HO catalysis. In order to discriminate three possible pathways proposed for the verdoheme ring-opening, we have examined reactions of the verdoheme-HO-1 complex with alkyl peroxides, namely MeOOH. Under reducing conditions, the MeOOH reaction afforded two novel products whose absorption spectra are similar to but slightly different from that of biliverdin. HPLC, ESI-MS, and NMR analysis show that these products are 1- and 19-methoxy-deoxy-biliverdins. The addition of a methoxy group at one end of the linear tetrapyrrole unambiguously indicates transient formation of the Fe-OOMe intermediate and rearrangement of its terminal methoxy group to the alpha-pyrrole carbon. The corresponding OH transfer of the Fe-OOH species is highly probable in the H2O2-dependent verdoheme degradation and is likely to be the case in the O2-dependent reaction catalyzed by HO as well.

  13. Crystal structure of peroxiredoxin from Aeropyrum pernix K1 complexed with its substrate, hydrogen peroxide.

    PubMed

    Nakamura, Tsutomu; Kado, Yuji; Yamaguchi, Takafumi; Matsumura, Hiroyoshi; Ishikawa, Kazuhiko; Inoue, Tsuyoshi

    2010-01-01

    Peroxiredoxin (Prx) reduces hydrogen peroxide and alkyl peroxides to water and corresponding alcohols, respectively. The reaction is dependent on a peroxidatic cysteine, whose sulphur atom nucleophilically attacks one of the oxygen atoms of the peroxide substrate. In spite of the many structural studies that have been carried out on this reaction, the tertiary structure of the hydrogen peroxide-bound form of Prx has not been elucidated. In this paper, we report the crystal structure of Prx from Aeropyrum pernix K1 in the peroxide-bound form. The conformation of the polypeptide chain is the same as that in the reduced apo-form. The hydrogen peroxide molecule is in close contact with the peroxidatic Cys50 and the neighbouring Thr47 and Arg126 side chain atoms, as well as with the main chain nitrogen atoms of Val49 and Cys50. Bound peroxide was also observed in the mutant C50S, in which the peroxidatic cysteine was replaced by serine. Therefore, the sulphur atom of the peroxidatic cysteine is not essential for peroxide binding, although it enhances the binding affinity. Hydrogen peroxide binds to the protein so that it fills the active site pocket. This study provides insight into the early stage of the Prx reaction.

  14. Overview of a professional tooth-whitening system containing 6.5% hydrogen peroxide whitening strips.

    PubMed

    Sagel, Paul A; Jeffers, Melissa E; Gibb, Roger D; Gerlach, Robert W

    2002-01-01

    Professionally dispensed, at-home tooth whitening began with 10% carbamide peroxide gels applied to the dentition with custom-made trays. In the 1990s, higher-concentration carbamide peroxide gels were introduced to achieve faster results. Today, 15% and 20% carbamide peroxide gels are commonly used. Recently, a new vital tooth-whitening technique that uses a flexible strip rather than a tray to apply a 5.3% hydrogen peroxide whitening gel was introduced. The new strip-based product was shown to provide whitening equivalent to a 10% carbamide peroxide tray with half the wear time. In addition, the strip eliminated the need to custom fabricate trays for each patient. This article provides an overview of a professionally distributed strip-based whitening system and reviews some of the clinical data which supports the efficacy of the product. This new whitening system includes 42 mandibular and 42 maxillary strips at a higher concentration of 6.5% hydrogen peroxide. In addition, the system also includes a novel dual-action whitening dentifrice to prevent future staining postbleaching and an extrasoft toothbrush. Clinically, the professionally distributed strip-based whitening system provided 96% more efficacy than a popular carbamide plus hydrogen peroxide (equivalent to 10% carbamide peroxide) tray system and 52% more whitening than the 5.3% hydrogen peroxide strip system.

  15. Physical properties of basic hydrogen peroxide solutions for use in singlet oxygen generators

    NASA Astrophysics Data System (ADS)

    Bakshin, Victor V.; Kalinovsky, V. V.; Konovalov, V. V.; Nikolaev, V. D.; Sobolev, R. E.; Shornikov, L. N.

    1998-12-01

    The physical properties of basic hydrogen peroxide solutions (BHP) such as viscosity, density, and freezing temperature as well as their variation during laser operation have been experimentally investigated. In these experiments (30 - 50%) commercial hydrogen peroxides have been used, containing stabilizers and an alkali of the following composition: 81.5% KOH and 5.5% K2CO3. The use of these substances for generation of singlet oxygen in the COIL has shown their good ability to operate. Consideration has been given to the possibilities of the basic hydrogen peroxide solutions recovery during the industrial COIL operation.

  16. Hydrogen peroxide enhances enterokinase-catalysed proteolytic cleavage of fusion protein.

    PubMed

    Cui, Taian; Gao, Yaojun; Ang, Cui X; Puah, Chum M; Gutte, Bernd; Lam, Yulin

    2008-01-01

    The effects of hydrogen peroxide on enterokinase catalysis were studied using several fusion proteins recombinantly produced from E. coli. It was demonstrated that hydrogen peroxide enhanced the rate of enterokinase cleavage reaction, leading to a faster release of the target peptide as discussed in patent WO07149053. Among the conditions tested, we observed that hydrogen peroxide could exert its effect on the cleavage of fusion proteins over a wide range of pH and temperature. This finding might provide a simple solution for the accelerated enterokinase cleavage of thermolabile fusion proteins at low temperature.

  17. Vital bleaching with a thin peroxide gel: the safety and efficacy of a professional-strength hydrogen peroxide whitening strip.

    PubMed

    Gerlach, Robert W; Sagel, Paul A

    2004-01-01

    Use of higher peroxide concentrations for professional at-home vital bleaching often balances two factors in patient compliance: whitening and tolerability. Development of a polyethylene strip coated with a very thin (0.10-millimeter) layer of 14 percent hydrogen peroxide gel (Crest Whitestrips Supreme, Procter & Gamble, Cincinnati)--which represents an increase in concentration and a decrease in amount of gel--was believed to allow for greater at-home whitening with little additional oral soft-tissue exposure to peroxide. The authors conducted a randomized, double-blind, two-week clinical trial with 38 adults to evaluate the safety and efficacy of twice-daily use of the thin, concentrated bleaching gel strip versus the effects of a control product (Crest Whitestrips, Procter & Gamble). The two products differed only in concentration (14 percent versus 6 percent) and gel layer thickness (0.10 mm versus 0.20 mm). The authors measured efficacy from digital images using the Commission Internationale de l'Eclairage L*a*b* color scale. They assessed safety via subject interviews and clinical examination and compared treatments using analysis of covariance. Relative to baseline color, both strip groups exhibited significant (P < .001) improvement in yellowness, brightness and composite color change. Between-group comparisons after two weeks demonstrated significant (P < .003) color improvement for the experimental strip relative to the control. Both products were well-tolerated generally. Despite the concentration differences, clinical examination of each group showed a similar low level (11 percent) of "minor oral irritation." Use of the thin 14 percent hydrogen peroxide gel strip resulted in greater whitening, including 42 to 49 percent greater improvement in tooth color and faster whitening onset than that seen with a 6 percent hydrogen peroxide whitening strip, without clinical evidence of increased oral-tissue irritation. Use of whitening strips with a thin

  18. Factors affecting the levels of hydrogen peroxide in rainwater

    NASA Astrophysics Data System (ADS)

    Deng, Yiwei; Zuo, Yuegang

    Measurements of hydrogen peroxide (H 2O 2) and several meteorological and chemical parameters were made for 34 rain events which occurred in Miami, Florida between April, 1995 and October, 1996. The measured H 2O 2 concentrations ranged from 0.3 to 38.6 μM with an average concentration of 6.9 μM. A strong seasonal dependence for H 2O 2 concentrations was observed during this period, with highest concentrations in the summer and lower levels in the winter, which corresponds to the stronger solar radiation and higher vaporization of volatile organic compounds (VOCs) in the summer and fall, and the weaker sunlight and lower vaporization in the winter and spring. Measurements also showed a significant increase trend of H 2O 2 with increasing ambient rainwater temperature. Rains that were out from lower latitude were exposed to higher solar irradiation and contained relatively higher levels of H 2O 2 than those from the north. All these observations indicate that photochemical reactions that involved volatile organic compounds are the predominant source of H 2O 2 observed in rainwater. During several individual rainstorms, H 2O 2 concentration was found to increase as a function of time due to electrical storm activities. This finding suggests that lightning could be an important factor that determines the level of H 2O 2 during thunderstorms. Statistical data showed that the highest concentrations of H 2O 2 were observed only in rains containing low levels of nonsea-salt sulfate (NSS), nitrate and hydrogen ion. H 2O 2 concentrations in continental originated rains were much lower than marine originated ones, indicating that air pollutants in continental rains could significantly deplete the H 2O 2 concentration in atmospheric gas-phase, clouds and rainwater.

  19. Role of internal thermodynamics in determining hydrogen tunneling in enzyme-catalyzed hydrogen transfer reactions.

    PubMed

    Rucker, J; Cha, Y; Jonsson, T; Grant, K L; Klinman, J P

    1992-11-24

    Previous investigations have indicated a role for hydrogen tunneling in the yeast alcohol dehydrogenase catalyzed oxidation of benzyl alcohol [Cha, Y., Murray, C. J., & Klinman, J. P. (1989) Science 243, 1325] and the bovine plasma amine oxidase catalyzed oxidation of benzylamine [Grant, K.L., & Klinman, J. P. (1989) Biochemistry 28,6597]. In the present studies, values of protium to tritium and deuterium to tritium isotope effects and their temperature dependencies have been measured using ring-substituted substrates for yeast alcohol dehydrogenase and bovine plasma amine oxidase, revealing tunneling in each case. The results of these studies indicate that hydrogen tunneling is a general phenomenon and is not limited to enzyme reactions with degenerate energy levels for bound substrates and products. An analysis of internal thermodynamics in the yeast alcohol dehydrogenase reaction shows that tunneling occurs when delta H degrees is endothermic and that the degree of tunneling appears to increase as delta H degrees decreases toward zero.

  20. Salidroside inhibits endogenous hydrogen peroxide induced cytotoxicity of endothelial cells.

    PubMed

    Zhao, Xingyu; Jin, Lianhai; Shen, Nan; Xu, Bin; Zhang, Wei; Zhu, Hongli; Luo, Zhengli

    2013-01-01

    Salidroside, a phenylpropanoid glycoside isolated from Rhodiola rosea L., shows potent antioxidant property. Herein, we investigated the protective effects of salidroside against hydrogen peroxide (H2O2)-induced oxidative damage in human endothelial cells (EVC-304). EVC-304 cells were incubated in the presence or absence of low steady states of H2O2 (3-4 µM) generated by glucose oxidase (GOX) with or without salidroside. 3(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT), superoxide dismutase (SOD), malondialdehyde (MDA), and glutathione (GSH) assays were performed, together with Hoechst 33258 staining and flow cytometric analysis using Annexin-V and propidium iodide (PI) label. The results indicated that salidroside pretreatment attenuated endogenous H2O2 induced apoptotic cell death in EVC-304 cells in a dose-dependent pattern. Furthermore, Western blot data revealed that salidroside inhibited activation of caspase-3, 9 and cleavage of poly(ADP-ribose) polymerase (PARP) induced by endogenous H2O2. It also decreased the expression of Bax and rescued the balance of pro- and anti-apoptotic proteins. All these results demonstrated that salidroside may present a potential therapy for oxidative stress in cardiovascular and cerebrovascular diseases.

  1. Anoxic stress leads to hydrogen peroxide formation in plant cells.

    PubMed

    Blokhina, O B; Chirkova, T V; Fagerstedt, K V

    2001-06-01

    Hydrogen peroxide (H2O2) was detected cytochemically in plant tissues during anoxia and re-oxygenation by transmission electron microscopy using its reaction with cerium chloride to produce electron dense precipitates of cerium perhydroxides. Anoxia-tolerant yellow flag iris (Iris pseudacorus) and rice (Oryza sativa), and anoxia-intolerant wheat (Triticum aestivum) and garden iris (Iris germanica) were used in the experiments. In all plants tested, anoxia and re-oxygenation increased H2O2 in plasma membranes and the apoplast. In the anoxia-tolerant species the response was delayed in time, and in highly tolerant I. pseudacorus plasma membrane associated H2O2 was detected only after 45 d of oxygen deprivation. Quantification of cerium precipitates showed a statistically significant increase in the amount of H2O2 caused by anoxia in wheat root meristematic tissue, but not in the anoxia-tolerant I. pseudacorus rhizome parenchyma. Formation of H2O2 under anoxia is considered mainly an enzymatic process (confirmed by an enzyme inhibition analysis) and is due to the trace amount of dissolved oxygen (below 10(-5) M) present in the experimental system. The data suggest oxidative stress is an integral part of oxygen deprivation stress, and emphasize the importance of the apoplast and plasma membrane in the development of the anoxic stress response.

  2. Ab initio calculation of infrared intensities for hydrogen peroxide

    NASA Technical Reports Server (NTRS)

    Rogers, J. D.; Hillman, J. J.

    1982-01-01

    Results of an ab initio SCF quantum mechanical study are used to derive estimates for the infrared intensities of the fundamental vibrations of hydrogen peroxide. Atomic polar tensors (APTs) were calculated on the basis of a 4-31G basis set, and used to derive absolute intensities for the vibrational transitions. Comparison of the APTs calculated for H2O2 with those previously obtained for H2O and CH3OH, and of the absolute intensities derived from the H2O2 APTs with those derived from APTs transferred from H2O and CH3OH, reveals the sets of values to differ by no more than a factor of two, supporting the validity of the theoretical calculation. Values of the infrared intensities obtained correspond to A1 = 14.5 km/mol, A2 = 0.91 km/mol, A3 = 0.058 km/mol, A4 = 123 km/mol, A5 = 46.2 km/mol, and A6 = 101 km/mol. Charge, charge flux and overlap contributions to the dipole moment derivatives are also computed.

  3. Hydrogen peroxide regulates cell adhesion through the redox sensor RPSA.

    PubMed

    Vilas-Boas, Filipe; Bagulho, Ana; Tenente, Rita; Teixeira, Vitor H; Martins, Gabriel; da Costa, Gonçalo; Jerónimo, Ana; Cordeiro, Carlos; Machuqueiro, Miguel; Real, Carla

    2016-01-01

    To become metastatic, a tumor cell must acquire new adhesion properties that allow migration into the surrounding connective tissue, transmigration across endothelial cells to reach the blood stream and, at the site of metastasis, adhesion to endothelial cells and transmigration to colonize a new tissue. Hydrogen peroxide (H2O2) is a redox signaling molecule produced in tumor cell microenvironment with high relevance for tumor development. However, the molecular mechanisms regulated by H2O2 in tumor cells are still poorly known. The identification of H2O2-target proteins in tumor cells and the understanding of their role in tumor cell adhesion are essential for the development of novel redox-based therapies for cancer. In this paper, we identified Ribosomal Protein SA (RPSA) as a target of H2O2 and showed that RPSA in the oxidized state accumulates in clusters that contain specific adhesion molecules. Furthermore, we showed that RPSA oxidation improves cell adhesion efficiency to laminin in vitro and promotes cell extravasation in vivo. Our results unravel a new mechanism for H2O2-dependent modulation of cell adhesion properties and identify RPSA as the H2O2 sensor in this process. This work indicates that high levels of RPSA expression might confer a selective advantage to tumor cells in an oxidative environment.

  4. Specific aquaporins facilitate the diffusion of hydrogen peroxide across membranes.

    PubMed

    Bienert, Gerd P; Møller, Anders L B; Kristiansen, Kim A; Schulz, Alexander; Møller, Ian M; Schjoerring, Jan K; Jahn, Thomas P

    2007-01-12

    The metabolism of aerobic organisms continuously produces reactive oxygen species. Although potentially toxic, these compounds also function in signaling. One important feature of signaling compounds is their ability to move between different compartments, e.g. to cross membranes. Here we present evidence that aquaporins can channel hydrogen peroxide (H2O2). Twenty-four aquaporins from plants and mammals were screened in five yeast strains differing in sensitivity toward oxidative stress. Expression of human AQP8 and plant Arabidopsis TIP1;1 and TIP1;2 in yeast decreased growth and survival in the presence of H2O2. Further evidence for aquaporin-mediated H2O2 diffusion was obtained by a fluorescence assay with intact yeast cells using an intracellular reactive oxygen species-sensitive fluorescent dye. Application of silver ions (Ag+), which block aquaporin-mediated water diffusion in a fast kinetics swelling assay, also reversed both the aquaporin-dependent growth repression and the H2O2-induced fluorescence. Our results present the first molecular genetic evidence for the diffusion of H2O2 through specific members of the aquaporin family.

  5. Genetic defects of hydrogen peroxide generation in the thyroid gland.

    PubMed

    Weber, G; Rabbiosi, S; Zamproni, I; Fugazzola, L

    2013-04-01

    Hydrogen peroxide (H2O2) is a key element in thyroid hormone biosynthesis. It is the substrate used by thyroid peroxidase for oxidation and incorporation of iodine into thyroglobulin, a process known as organification. The main enzymes composing the H2O2-generating system are the dual oxidase 2 (DUOX2) and the recently described DUOX maturation factor 2 (DUOXA2). Defects in these reactions lead to reduced thyroid hormone synthesis and hypothyroidism, with consequent increased TSH secretion and goiter. Since the first report in 2002 of DUOX2 mutations causing congenital hypothryoidism (CH), to date 25 different mutations have been described. Affected patients show a positive perchlorate discharge test and high phenotypic variability, ranging from transient to permanent forms of CH. Up to now, only two cases of CH due to DUOXA2 defects have been published. They also suggest the existence of a great genotype-phenotype variability. The phenotypic expression is probably influenced by genetic background and environmental factors. DUOX and DUOXA constitute a redundant system in which DUOX1/DUOXA1 can at least partially replace the function of DUOX2/DUOXA2. Furthermore, increased nutritional iodide could ensure a better use of H2O2 provided by DUOX1.

  6. Solvothermal method to prepare graphene quantum dots by hydrogen peroxide

    NASA Astrophysics Data System (ADS)

    Tian, Renbing; Zhong, Suting; Wu, Juan; Jiang, Wei; Shen, Yewen; Jiang, Wei; Wang, Tianhe

    2016-10-01

    Graphene quantum dots (GQDs) have been synthesized by different chemical methods in recent years. For conventional chemical methods, it is inevitable to introduce a large amount of impurities in the preparation process. Long time of dialysis process increases the time cost extremely. Herein, we report a one-step solvothermal method for synthesizing GQDs with the application of hydrogen peroxide in N, N-Dimethylformamide (DMF) environment, which completely avoids the use of concentrated sulphuric acid and nitric acid to treat raw material and introduces no impurity in whole preparation process simultaneously for the first time. Pure GQDs can be obtained after evaporation/redissolution and filtration process with a strong blue emission at 15% quantum yield. This solvothermal method, not requiring dialysis process and complicated equipments, exhibits simple, eco-friendly and low time-cost properties. Besides high quantum yields, the as-prepared GQDs also show good photoluminescence stability in different pH conditions. The optical properties, morphology and structure of GQDs were studied by various equipments, implying potential application in biomedical fields and electronic device.

  7. Green hypergolic combination: Diethylenetriamine-based fuel and hydrogen peroxide

    NASA Astrophysics Data System (ADS)

    Kang, Hongjae; Kwon, Sejin

    2017-08-01

    The present research dealt with the concept of green hypergolic combination to replace the toxic hypergolic combinations. Hydrogen peroxide was selected as a green oxidizer. A novel recipe for the non-toxic hypergolic fuel (Stock 3) was suggested. Sodium borohydride was blended into the mixture of energetic hydrocarbon solvents as an ignition source for hypergolic ignition. The main ingredient of the mixture was diethylenetriamine. By mixing some amount of tetrahydrofuran with diethylenetriamine, the mixture became more flammable and volatile. The mixture of Stock 3 fuel remained stable for four months in the lab scale storability test. Through a simple drop test, the hypergolicity of the green hypergolic combination was verified. Comparing to the toxic hypergolic combination MMH/NTO as the reference, the theoretical performance of the green hypergolic combination would be achieved about 96.7% of the equilibrium specific impulse and about 105.7% of the density specific impulse. The applicability of the green hypergolic combination was successfully confirmed through the static hot-fire tests using 500 N scale hypergolic thruster.

  8. Preliminary flight test of hydrogen peroxide retro-propulsion module

    NASA Astrophysics Data System (ADS)

    An, Sungyong; Jo, Sungkwon; Wee, Jeonghyun; Yoon, Hosung; Kwon, Sejin

    2010-09-01

    In this paper, we present the development of a retro-thruster, the design of a retro-propulsion module, and a preliminary flight of the module in a landing demonstration. First, a retro-monopropellant thruster with the maximum thrust of 350 N that employs hydrogen peroxide as a monopropellant was developed. It's thrust force, efficiency of characteristic velocity, and specific impulse were evaluated during the course of it's development. To control the thrust force, two solenoid valves and a pulse width modulation (PWM) flow control valve were incorporated into the thruster design. Second, a retro-propulsion module with a wet mass of 23 kg was designed and fabricated. All the required components including tanks, propellant tubes, a pressure regulator, valves, a retro-thruster, and support structure were integrated into the module. Finally, a preliminary flight test with thrust and altitude control was carried out successfully. In this test, the throttling of the thrust force and altitude control was performed manually for safety purposes.

  9. Direct synthesis of hydrogen peroxide from plasma-water interactions

    PubMed Central

    Liu, Jiandi; He, Bangbang; Chen, Qiang; Li, Junshuai; Xiong, Qing; Yue, Guanghui; Zhang, Xianhui; Yang, Size; Liu, Hai; Liu, Qing Huo

    2016-01-01

    Hydrogen peroxide (H2O2) is usually considered to be an important reagent in green chemistry since water is the only by-product in H2O2 involved oxidation reactions. Early studies show that direct synthesis of H2O2 by plasma-water interactions is possible, while the factors affecting the H2O2 production in this method remain unclear. Herein, we present a study on the H2O2 synthesis by atmospheric pressure plasma-water interactions. The results indicate that the most important factors for the H2O2 production are the processes taking place at the plasma-water interface, including sputtering, electric field induced hydrated ion emission, and evaporation. The H2O2 production rate reaches ~1200 μmol/h when the liquid cathode is purified water or an aqueous solution of NaCl with an initial conductivity of 10500 μS cm−1. PMID:27917925

  10. Nitric oxide formation from hydroxylamine by myoglobin and hydrogen peroxide.

    PubMed

    Taira, J; Misík, V; Riesz, P

    1997-10-20

    Hydroxylamine (HA), which is a natural product of mammalian cells, has been shown to possess vasodilatory properties in several model systems. In this study, HA and methyl-substituted hydroxylamines, N-methylhydroxylamine (NMHA) and N,N-dimethylhydroxylamine (NDMHA), have been tested for their ability to generate free diffusible nitric oxide (NO) in the presence of myoglobin (Mb) and hydrogen peroxide. A NO-specific conversion of 2-(4-carboxyphenyl)-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide (carboxy-PTIO) to 2-(4-carboxyphenyl)-4,4,5,5-tetramethylimidazoline-1-oxyl (carboxy-PTI), measured by electron spin resonance (ESR) spectroscopy, along with nitrite and nitrate production, was observed for HA but not for NMHA and NDMHA. ESR measurements at 77 K showed the formation of the ferrous nitrosyl myoglobin, Mb-NO, in the reaction mixtures containing Mb, H2O2 and HA. Our data also demonstrate that Mb-NO is an end product of the reaction pathway involving Mb, H2O2 and HA, rather than a reaction intermediate in the formation of NO. In summary, our results demonstrate a possible pathway of NO formation from HA, however, the significance of this mechanism for bioactivation of HA in vivo is unknown at the present time.

  11. Light-sensing via hydrogen peroxide and a peroxiredoxin

    PubMed Central

    Bodvard, Kristofer; Peeters, Ken; Roger, Friederike; Romanov, Natalie; Igbaria, Aeid; Welkenhuysen, Niek; Palais, Gaël; Reiter, Wolfgang; Toledano, Michel B.; Käll, Mikael; Molin, Mikael

    2017-01-01

    Yeast lacks dedicated photoreceptors; however, blue light still causes pronounced oscillations of the transcription factor Msn2 into and out of the nucleus. Here we show that this poorly understood phenomenon is initiated by a peroxisomal oxidase, which converts light into a hydrogen peroxide (H2O2) signal that is sensed by the peroxiredoxin Tsa1 and transduced to thioredoxin, to counteract PKA-dependent Msn2 phosphorylation. Upon H2O2, the nuclear retention of PKA catalytic subunits, which contributes to delayed Msn2 nuclear concentration, is antagonized in a Tsa1-dependent manner. Conversely, peroxiredoxin hyperoxidation interrupts the H2O2 signal and drives Msn2 oscillations by superimposing on PKA feedback regulation. Our data identify a mechanism by which light could be sensed in all cells lacking dedicated photoreceptors. In particular, the use of H2O2 as a second messenger in signalling is common to Msn2 oscillations and to light-induced entrainment of circadian rhythms and suggests conserved roles for peroxiredoxins in endogenous rhythms. PMID:28337980

  12. Optimization of Hydrogen Peroxide Detection for a Methyl Mercaptan Biosensor

    PubMed Central

    Li, Zhan-Hong; Guedri, Houssemeddine; Viguier, Bruno; Sun, Shi-Gang; Marty, Jean-Louis

    2013-01-01

    Several kinds of modified carbon screen printed electrodes (CSPEs) for amperometric detection of hydrogen peroxide (H2O2) are presented in order to propose a methyl mercaptan (MM) biosensor. Unmodified, carbon nanotubes (CNTs), cobalt phthalocyanine (CoPC), Prussian blue (PB), and Os-wired HRP modified CSPE sensors were fabricated and tested to detect H2O2, applying a potential of +0.6 V, +0.6 V, +0.4 V, −0.2 V and −0.1 V (versus Ag/AgCl), respectively. The limits of detection of these electrodes for H2O2 were 3.1 μM, 1.3 μM, 71 nM, 1.3 μM, 13.7 nM, respectively. The results demonstrated that the Os-wired HRP modified CSPEs gives the lowest limit of detection (LOD) for H2O2 at a working potential as low as −0.1 V. Os-wired HRP is the optimum choice for establishment of a MM biosensor and gives a detection limit of 0.5 μM. PMID:23591963

  13. Changes in synaptic transmission produced by hydrogen peroxide.

    PubMed

    Colton, C A; Colton, J S; Gilbert, D L

    1986-01-01

    The effect of hydrogen peroxide (H2O2) on excitatory and inhibitory synaptic transmission was studied at the lobster neuromuscular junction. H2O2 produced a dose dependent decrease in the amplitude of the junction potential (Vejp). This decrease was due to changes in both presynaptic transmitter release and the postsynaptic response to the neurotransmitter. Observed presynaptic changes due to exposure to H2O2 were a decrease in the amount of transmitter released, that is, quantal content, as well as a decrease in the fast facilitation, that is, the amplitude increase of successive excitatory junction potentials at a rate of 3 Hz. To discern postsynaptic changes, glutamate, the putative excitatory neurotransmitter for this preparation was applied directly to the bathing medium in order to bypass the presynaptic release process. H2O2 produced a decreased response of the glutamate receptor/ionophore. The action of H2O2 was not selective to excitatory (glutamate-mediated) transmission because inhibitory (GABA-mediated) transmission was also depressed by H2O2. This effect was primarily presynaptic since H2O2 produced no change in the postsynaptic response to applied GABA.

  14. Hydrogen peroxide: a Jekyll and Hyde signalling molecule.

    PubMed

    Gough, D R; Cotter, T G

    2011-10-06

    Reactive oxygen species (ROS) are a group of molecules produced in the cell through metabolism of oxygen. Endogenous ROS such as hydrogen peroxide (H₂O₂) have long been recognised as destructive molecules. The well-established roles they have in the phagosome and genomic instability has led to the characterisation of these molecules as non-specific agents of destruction. Interestingly, there is a growing body of literature suggesting a less sinister role for this Jekyll and Hyde molecule. It is now evident that at lower physiological levels, H₂O₂ can act as a classical intracellular signalling molecule regulating kinase-driven pathways. The newly discovered biological functions attributed to ROS include proliferation, migration, anoikis, survival and autophagy. Furthermore, recent advances in detection and quantification of ROS-family members have revealed that the diverse functions of ROS can be determined by the subcellular source, location and duration of these molecules within the cell. In light of this confounding paradox, we will examine the factors and circumstances that determine whether H₂O₂ acts in a pro-survival or deleterious manner.

  15. Hydrogen peroxide: a Jekyll and Hyde signalling molecule

    PubMed Central

    Gough, D R; Cotter, T G

    2011-01-01

    Reactive oxygen species (ROS) are a group of molecules produced in the cell through metabolism of oxygen. Endogenous ROS such as hydrogen peroxide (H2O2) have long been recognised as destructive molecules. The well-established roles they have in the phagosome and genomic instability has led to the characterisation of these molecules as non-specific agents of destruction. Interestingly, there is a growing body of literature suggesting a less sinister role for this Jekyll and Hyde molecule. It is now evident that at lower physiological levels, H2O2 can act as a classical intracellular signalling molecule regulating kinase-driven pathways. The newly discovered biological functions attributed to ROS include proliferation, migration, anoikis, survival and autophagy. Furthermore, recent advances in detection and quantification of ROS-family members have revealed that the diverse functions of ROS can be determined by the subcellular source, location and duration of these molecules within the cell. In light of this confounding paradox, we will examine the factors and circumstances that determine whether H2O2 acts in a pro-survival or deleterious manner. PMID:21975295

  16. Heterogeneous uptake of gaseous hydrogen peroxide on mineral dust.

    PubMed

    Zhou, Li; Wang, Weigang; Ge, Maofa; Tong, Shengrui

    2016-02-01

    The heterogeneous uptake processes of hydrogen peroxide on Arizona test dust and two types of authentic Chinese mineral dusts, i.e., Inner Mongolia desert dust and Xinjiang calciferous dust, were investigated using a Knudsen cell reactor coupled with a quadrupole mass spectrometer. The uptake coefficients were measured as a function of the initial concentration of H2O2 from 2.6 × 10(11) to 1.2 × 10(12)molecules/cm(3), and the temperature dependence of the uptake coefficients was investigated over a range from 253 to 313K. The concentration of H2O2 showed little effect on the uptake coefficients of these heterogeneous processes. As a function of temperature, the initial uptake coefficients decrease with increasing temperature, whereas the steady state uptake coefficients of Arizona test dust and Inner Mongolia desert dust increase with increasing temperature. Implications for the understanding of the uptake processes onto mineral dust samples were also discussed. Copyright © 2015. Published by Elsevier B.V.

  17. Hydrogen peroxide thermochemical oscillator as driver for primordial RNA replication.

    PubMed

    Ball, Rowena; Brindley, John

    2014-06-06

    This paper presents and tests a previously unrecognized mechanism for driving a replicating molecular system on the prebiotic earth. It is proposed that cell-free RNA replication in the primordial soup may have been driven by self-sustained oscillatory thermochemical reactions. To test this hypothesis, a well-characterized hydrogen peroxide oscillator was chosen as the driver and complementary RNA strands with known association and melting kinetics were used as the substrate. An open flow system model for the self-consistent, coupled evolution of the temperature and concentrations in a simple autocatalytic scheme is solved numerically, and it is shown that thermochemical cycling drives replication of the RNA strands. For the (justifiably realistic) values of parameters chosen for the simulated example system, the mean amount of replicant produced at steady state is 6.56 times the input amount, given a constant supply of substrate species. The spontaneous onset of sustained thermochemical oscillations via slowly drifting parameters is demonstrated, and a scheme is given for prebiotic production of complementary RNA strands on rock surfaces.

  18. Hydrogen peroxide thermochemical oscillator as driver for primordial RNA replication

    PubMed Central

    Ball, Rowena; Brindley, John

    2014-01-01

    This paper presents and tests a previously unrecognized mechanism for driving a replicating molecular system on the prebiotic earth. It is proposed that cell-free RNA replication in the primordial soup may have been driven by self-sustained oscillatory thermochemical reactions. To test this hypothesis, a well-characterized hydrogen peroxide oscillator was chosen as the driver and complementary RNA strands with known association and melting kinetics were used as the substrate. An open flow system model for the self-consistent, coupled evolution of the temperature and concentrations in a simple autocatalytic scheme is solved numerically, and it is shown that thermochemical cycling drives replication of the RNA strands. For the (justifiably realistic) values of parameters chosen for the simulated example system, the mean amount of replicant produced at steady state is 6.56 times the input amount, given a constant supply of substrate species. The spontaneous onset of sustained thermochemical oscillations via slowly drifting parameters is demonstrated, and a scheme is given for prebiotic production of complementary RNA strands on rock surfaces. PMID:24647902

  19. Toxic DNA damage by hydrogen peroxide through the Fenton reaction in vivo and in vitro.

    PubMed

    Imlay, J A; Chin, S M; Linn, S

    1988-04-29

    Exposure of Escherichia coli to low concentrations of hydrogen peroxide results in DNA damage that causes mutagenesis and kills the bacteria, whereas higher concentrations of peroxide reduce the amount of such damage. Earlier studies indicated that the direct DNA oxidant is a derivative of hydrogen peroxide whose formation is dependent on cell metabolism. The generation of this oxidant depends on the availability of both reducing equivalents and an iron species, which together mediate a Fenton reaction in which ferrous iron reduces hydrogen peroxide to a reactive radical. An in vitro Fenton system was established that generates DNA strand breaks and inactivates bacteriophage and that also reproduces the suppression of DNA damage by high concentrations of peroxide. The direct DNA oxidant both in vivo and in this in vitro system exhibits reactivity unlike that of a free hydroxyl radical and may instead be a ferryl radical.

  20. Toxic DNA Damage by Hydrogen Peroxide through the Fenton Reaction in vivo and in vitro

    NASA Astrophysics Data System (ADS)

    Imlay, James A.; Chin, Sherman M.; Linn, Stuart

    1988-04-01

    Exposure of Escherichia coli to low concentrations of hydrogen peroxide results in DNA damage that causes mutagenesis and kills the bacteria, whereas higher concentrations of peroxide reduce the amount of such damage. Earlier studies indicated that the direct DNA oxidant is a derivative of hydrogen peroxide whose formation is dependent on cell metabolism. The generation of this oxidant depends on the availability of both reducing equivalents and an iron species, which together mediate a Fenton reaction in which ferrous iron reduces hydrogen peroxide to a reactive radical. An in vitro Fenton system was established that generates DNA strand breaks and inactivates bacteriophage and that also reproduces the suppression of DNA damage by high concentrations of peroxide. The direct DNA oxidant both in vivo and in this in vitro system exhibits reactivity unlike that of a free hydroxyl radical and may instead be a ferryl radical.

  1. Real-time mapping of a hydrogen peroxide concentration profile across a polymicrobial bacterial biofilm using scanning electrochemical microscopy.

    PubMed

    Liu, Xiuhui; Ramsey, Matthew M; Chen, Xiaole; Koley, Dipankar; Whiteley, Marvin; Bard, Allen J

    2011-02-15

    Quantitative detection of hydrogen peroxide in solution above a Streptococcus gordonii (Sg) bacterial biofilm was studied in real time by scanning electrochemical microscopy (SECM). The concentration of hydrogen peroxide was determined to be 0.7 mM to 1.6 mM in the presence of 10 mM glucose over a period of 2 to 8 h. The hydrogen peroxide production measured was higher near the biofilm surface in comparison to Sg grown planktonically. Differential hydrogen peroxide production was observed both by fluorometric as well as by SECM measurements. The interaction between two different species in a bacterial biofilm of Sg and Aggregatibacter actinomycetemcomitans (Aa) in terms of hydrogen peroxide production was also studied by SECM. One-directional y-scan SECM measurements showed the unique spatial mapping of hydrogen peroxide concentration across a mixed species biofilm and revealed that hydrogen peroxide concentration varies greatly dependent upon local species composition.

  2. Recent advances in osmium-catalyzed hydrogenation and dehydrogenation reactions.

    PubMed

    Chelucci, Giorgio; Baldino, Salvatore; Baratta, Walter

    2015-02-17

    CONSPECTUS: A current issue in metal-catalyzed reactions is the search for highly efficient transition-metal complexes affording high productivity and selectivity in a variety of processes. Moreover, there is also a great interest in multitasking catalysts that are able to efficiently promote different organic transformations by careful switching of the reaction parameters, such as temperature, solvent, and cocatalyst. In this context, osmium complexes have shown the ability to catalyze efficiently different types of reactions involving hydrogen, proving at the same time high thermal stability and simple synthesis. In the catalytic reduction of C═X (X = O, N) bonds by both hydrogenation (HY) and transfer hydrogenation (TH) reactions, the most interest has been focused on homogeneous systems based on rhodium, iridium, and in particular ruthenium catalysts, which have proved to catalyze chemo- and stereoselective hydrogenations with remarkable efficiency. By contrast, osmium catalysts have received much less attention because they are considered less active on account of their slower ligand exchange kinetics. Thus, this area remained almost neglected until recent studies refuted these prejudices. The aim of this Account is to highlight the impressive developments achieved over the past few years by our and other groups on the design of new classes of osmium complexes and their applications in homogeneous catalytic reactions involving the hydrogenation of carbon-oxygen and carbon-nitrogen bonds by both HY and TH reactions as well as in alcohol deydrogenation (DHY) reactions. The work described in this Account demonstrates that osmium complexes are emerging as powerful catalysts for asymmetric and non-asymmetric syntheses, showing a remarkably high catalytic activity in HY and TH reactions of ketones, aldehydes, imines, and esters as well in DHY reactions of alcohols. Thus, for instance, the introduction of ligands with an NH function, possibly in combination with a

  3. Treatment of Aroclor 1016 contaminated soil by hydrogen peroxide: laboratory column study.

    PubMed

    Viisimaa, Marika; Veressinina, Jelena; Goi, Anna

    2012-09-01

    The potential and feasibility of treating soil contaminated with electrical insulating oil, Aroclor 1016, containing polychlorinated biphenyls (PCBs) with stabilized hydrogen peroxide were evaluated using columns packed with soils of two different matrixes. The column experiments showed that PCBs degraded by the stabilized hydrogen peroxide treatment in both soil matrixes, although the efficacy of the treatment depended strongly on the soil characteristics. The removal of PCB-containing oil was higher in sandy silt soil than in sandy soil. While a higher iron content promoted hydrogen peroxide oxidation of the contaminant in sandy silt soil, lower permeability and higher organic matter content contributed to an oxidation decrease as a function of depth. Dehydrogenase activity measurements indicated no substantial changes in microbial activity during the treatment of both sandy and sandy silt soils, thus offering opportunities to apply the hydrogen peroxide treatment to the remediation of PCB-contaminated soil.

  4. Certification of vapor phase hydrogen peroxide sterilization process for spacecraft application

    NASA Technical Reports Server (NTRS)

    Rohatgi, N.; Schubert, W.; Koukol, R.; Foster, T. L.; Stabekis, P. D.

    2002-01-01

    This paper describes the selection process and research activities JPL is planning to conduct for certification of hydrogen peroxide as a NASA approved technique for sterilization of various spacecraft parts/components and entire modern spacecraft.

  5. ENHANCED BIOREMEDIATION UTILIZING HYDROGEN PEROXIDE AS A SUPPLEMENTAL SOURCE OF OXYGEN: A LABORATORY AND FIELD STUDY

    EPA Science Inventory

    Laboratory and field scale studies were conducted to investigate the feasibility of using hydrogen peroxide as a supplemental source of oxygen for bioremediation of an aviation gasoline fuel spill. Field samples of aviation gasoline contaminated aquifer material were artificially...

  6. Certification of vapor phase hydrogen peroxide sterilization process for spacecraft application

    NASA Technical Reports Server (NTRS)

    Rohatgi, N.; Schubert, W.; Koukol, R.; Foster, T. L.; Stabekis, P. D.

    2002-01-01

    This paper describes the selection process and research activities JPL is planning to conduct for certification of hydrogen peroxide as a NASA approved technique for sterilization of various spacecraft parts/components and entire modern spacecraft.

  7. ENVIRONMENTAL TECHNOLOGY VERIFICATION REPORT: BIOQUELL, INC. CLARIS C HYDROGEN PEROXIDE GAS GENERATOR

    EPA Science Inventory

    The Environmental Technology Verification report discusses the technology and performance of the Clarus C Hydrogen Peroxide Gas Generator, a biological decontamination device manufactured by BIOQUELL, Inc. The unit was tested by evaluating its ability to decontaminate seven types...

  8. HOMOGENEOUS CATALYSTS FOR THE PARTIAL-OXYGENATION OF SATURATED HYDROCARBONS WITH HYDROGEN PEROXIDE

    EPA Science Inventory

    The development of catalysts with the capacity to activate green oxidants, such as hydrogen peroxide and molecular oxygen, can offer an environmentally sound pathway for hydrocarbon oxidation. Furthermore, by including the concepts of green chemistry and pollution prevention one ...

  9. ENVIRONMENTAL TECHNOLOGY VERIFICATION REPORT: BIOQUELL, INC. CLARIS C HYDROGEN PEROXIDE GAS GENERATOR

    EPA Science Inventory

    The Environmental Technology Verification report discusses the technology and performance of the Clarus C Hydrogen Peroxide Gas Generator, a biological decontamination device manufactured by BIOQUELL, Inc. The unit was tested by evaluating its ability to decontaminate seven types...

  10. A HIGHLY EFFICIENT OXIDATION OF CYCLOHEXANE OVER VPO CATALYSTS USING HYDROGEN PEROXIDE

    EPA Science Inventory

    An unprecedented and highly efficient oxidation of cyclohexane to cyclohexanol and cyclohexanone is accomplished over calcined vanadium phosphorus oxide (VPO) catalysts in a relatively mild condition using hydrogen peroxide under a nitrogen atmosphere.

  11. ENHANCED BIOREMEDIATION UTILIZING HYDROGEN PEROXIDE AS A SUPPLEMENTAL SOURCE OF OXYGEN: A LABORATORY AND FIELD STUDY

    EPA Science Inventory

    Laboratory and field scale studies were conducted to investigate the feasibility of using hydrogen peroxide as a supplemental source of oxygen for bioremediation of an aviation gasoline fuel spill. Field samples of aviation gasoline contaminated aquifer material were artificially...

  12. Development of technology of hydrogen peroxide water treatment with use of homogeneous or heterogeneous catalysts

    NASA Astrophysics Data System (ADS)

    Gutenyev, V. V.; Azhgirevich, A. I.; Kiryanova, L. F.; Gutenyeva, Ye. N.

    2003-04-01

    A flow chart of water disinfection by hydrogen peroxide with the use, as a catalyst, of manganese dioxide and titanium dioxide, as well as of natural catalysts, such as hopcolite, pyrolusite, rutil. The analysis of collected data shows that combination of hydrogen peroxide with hopcolite powder appears to be the most effective. Another positive aspect of the mentioned combination is enabling (by hopcolite) the water treated by hydrogen peroxide to continuously resist secondary bacteriological contamination. This flow chart enables us to increase the effectiveness of disinfection of hydrogen peroxide, which reduces human impact on environment. In order to improve bactericidal effects of hopcolite we loaded the hopcolite powder with metallic silver particles. In a series of experiments held both with environmental water and with model solutions we found the ability to neutralize artificially introduced infection (102 cells per liter) in 1.5-2 days.

  13. Influence of acid etching on hydrogen peroxide diffusion through human dentin.

    PubMed

    Camps, Jean; Pommel, Ludovic; Aubut, Virginie; About, Imad

    2010-06-01

    To evaluate the influence of dentin etching with phosphoric acid on hydrogen peroxide diffusion through human dentin in internal bleaching. 46 human premolars were extracted for orthodontic reasons from adolescents. The teeth were endodontically treated and a flat defect was created at the enamel-cementum junction. The teeth were divided into two groups: the access cavity was etched for 30 seconds with 35% H3PO4 in the first group and left intact in the second group. The teeth were filled with 20 microL of 35% hydrogen peroxide gel. The receiving medium on the other side was renewed at Day 1, Day 2 and Day 7 to quantify the diffusing hydrogen peroxide. An analysis of variance was performed to compare the diffusion between the two groups. This work demonstrated a higher hydrogen peroxide diffusion when the access cavity was etched (P < 0.01).

  14. MICROWAVE-EXPEDITED OLEFIN EPOXIDATION OVER HYDROTALCITES USING HYDROGEN PEROXIDE AND ACETONITRILE

    EPA Science Inventory

    An efficient microwave-assisted expoxidation of olefins is described over hydrotalcite catalysts in the presence of hydrogen peroxide and acetonitrile. This general and selective protocol is extremely fast and is applicable to a wide variety of subtrates.

  15. An automated system for the measurement of hydrogen peroxide in industrial applications

    PubMed Central

    Westbroek, Philippe; Temmerman, Edward; Kiekens, Paul; Govaert, Filip

    1998-01-01

    An automated sensor system for the continuous and in-line measurement of hydrogen peroxide in industrial applications is described. The hydrogen peroxide concentration can be measured over the entire pH range, over a wide concentration range of hydrogen peroxide (10-3 70 g/l), from 0 to 70°C, and with high precision and accuracy (errors less than 1% ). The system consists of a bypass in which the necessary electrodes are positioned and electronically controlled. The sensor is very selective for hydrogen peroxide, easy to instal, and it is stable for at least two months after calibration. The calibration can be done in the process solution during a running process. PMID:18924833

  16. Effect of hydrogen peroxide treatment on the properties of wool fabric

    NASA Astrophysics Data System (ADS)

    Wang, Xin; Shen, Xiaolin; Xu, Weilin

    2012-10-01

    In this study, hydrogen peroxide treatment was applied to improve the surface wettability, moisture transfer properties and other related properties of wool fabric. SEM images showed the tip of wool scale was smoothened and parts of the scale were peeled off after hydrogen peroxide treatment. The time for a water droplet to sink into the fabric could decrease to less than 1 s and the wicking properties of wool fabrics were dramatically improved after hydrogen peroxide treatment. Shrinkage and whiteness of the fabric were improved due to the modification of scale and the bleaching effect of hydrogen peroxide, respectively. The fabrics became weaker and ductile with less than 4% weight loss. This study would benefit further application of wool fiber in summer clothing in which the surface wettability and moisture transfer properties are essential and determinative.

  17. Ground-based Infrared Observations of Water Vapor and Hydrogen Peroxide in the Atmosphere of Mars

    NASA Astrophysics Data System (ADS)

    Encrenaz, T.; Greathouse, T. K.; Bitner, M.; Kruger, A.; Richter, M. J.; Lacy, J. H.; Bézard, B.; Fouchet, T.; Lefevre, F.; Forget, F.; Atreya, S. K.

    2008-11-01

    Ground-based observations of water vapor and hydrogen peroxide have been obtained in the thermal infrared range, using the TEXES instrument at the NASA Infrared Telescope Facility, for different times of the seasonal cycle.

  18. Involvement of hydrogen peroxide in the regulation of senescence in pear.

    PubMed

    Brennan, T; Frenkel, C

    1977-03-01

    Endogenous peroxide levels in pear fruit (Pyrus communis) were measured using a titanium assay method, and were found to increase during senescence in both Bartlett and Bosc varieties. Application of glycolic acid or xanthine, serving as substrates for the formation of H(2)O(2), increased the peroxide content of the tissue and accelerated the onset of ripening, as measured by increased softening and ethylene evolution. Application of ethylene also induced increased peroxide levels. Ripening processes were similarly promoted when peroxides were conserved by inhibiting the activity of catalase with hydroxylamine or potassium cyanide. By comparison, the inhibition of glycolate oxidase with alphahydroxy-2-pyridinemethanesulfonic acid decreased the peroxide content of the tissue and delayed the onset of ripening. These results indicate that the onset of ripening correlates with the peroxide content of fruit tissues as occurring under normal conditions or as influenced by the treatments. Hydrogen peroxide may be involved in oxidative processes required in the initiation and the promotion of ripening.

  19. [Mechanism of oxidation reaction of NADH models and phynylglyoxal with hydrogen peroxide. Hypothesis on separate transport of hydrogen and electron atom in certain enzymatic reactions with the participation of NADH and NADPH].

    PubMed

    Iasnikov, A A; Ponomarenko, S P

    1976-05-01

    Kinetics of co-oxidation of 1-benzen-3-carbamido-1,4-dihydropyridine (BDN) and phenylglyoxal (PG) with hydrogen peroxide is studied. Dimeric product (di-e11-benzen-5-carbamido-1,2-dihydropyridyl-2]) is found to be formed at pH 9, and quaternal pyridinium salt (BNA)--at pH 7. Molecular oxigen is determined to participate in the reaction at pH 7. Copper (II) ions catalyze this process. Significant catalytic effect of p-dinitrobenzen (p-DNB) is found. The reaction mechanism is postulated to form hydroperoxide from PG and hydrogen peroxide which are capable to split the hydrogen attom from dihydropyridine, molecular oxigen or p-DNB being an acceptor of the electrone. Hypothesis on separate transfer of hydrogen atom and electrone in biological systems are proposed.

  20. Developing Planetary Protection Technology: Recurrence of Hydrogen Peroxide Resistant Microbes from Spacecraft Assembly Facilities

    NASA Astrophysics Data System (ADS)

    Kempf, M. J.; Chen, F.; Quigley, M. S.; Pillai, S.; Kern, R.; Venkateswaran, K.

    2001-12-01

    Hydrogen peroxide vapor is currently the sterilant-of-choice for flight hardware because it is a low-heat sterilization process suitable for use with various spacecraft components. Hydrogen peroxide is a strong oxidizing agent that produces hydroxyl free radicals ( .OH) which attack essential cell components, including lipids, proteins, and DNA. Planetary protection research efforts at the Jet Propulsion Laboratory (JPL) are focused on developing cleaning and sterilization technologies for spacecraft preparation prior to launch. These efforts include research to assess the microbial diversity of spacecraft assembly areas and any extreme characteristics these microbes might possess. Previous studies have shown that some heat-tolerant Bacillus species isolated from the JPL Spacecraft Assembly Facility (SAF) are resistant to recommended hydrogen peroxide vapor sterilization exposures. A Bacillus species, which was related to a hydrogen peroxide resistant strain, was repeatedly isolated from various locations in the JPL-SAF. This species was found in both unclassified (entrance floors, ante-room, and air-lock) and classified (class 100K) (floors, cabinet tops, and air) areas. The phylogenetic affiliation of these strains was carried out using biochemical tests and 16S rDNA sequencing. The 16S rDNA analysis showed >99% sequence similarity to Bacillus pumilus. In order to understand the epidemiology of these strains, a more highly evolved gene (topoisomerase II β -subunit, gyrB) was also sequenced. Among 4 clades, one cluster, comprised of 3 strains isolated from the air-lock area, tightly aligned with the B. pumilus ATCC 7061 type strain (97%). The gyrB sequence similarity of this clade was only 91% with the 3 other clades. The genetic relatedness of these strains, as per pulse field gel electrophoresis patterns, will be presented. The vegetative cells and spores of a number of isolates were tested for their hydrogen peroxide resistance. Cells and spores were

  1. Efficacy of hydrogen peroxide to control saprolegniasis on channel catfish (Ictalurus punctatus) eggs

    USGS Publications Warehouse

    Rach, J.J.; Valentine, J.J.; Schreier, T.M.; Gaikowski, M.P.; Crawford, T.G.

    2004-01-01

    The efficacy of hydrogen peroxide to control mortality associated with saprolegniasis in channel catfish (Ictalurus punctatus) eggs was evaluated at the Lost Valley State Fish Hatchery (Warsaw, MO). Two efficacy trials were conducted. In Trial 1, channel catfish eggs in their natural gelatinous matrix were treated with hydrogen peroxide at 0, 500, and 750 mg l(-1). Channel catfish eggs in Trial 2 had the gelatinous matrix removed before treatment with hydrogen peroxide at 0 and 500 mg l(-1). Each treatment regimen was tested in triplicate and each egg jar contained similar to 17,400 eggs. Hydrogen peroxide was administered as a 15-min flow-through treatment applied once daily for a total of six applications. Control jars were similarly treated with culture water. Samples of exposure water were collected during each treatment and analyzed to verify actual treatment concentrations. Hydrogen peroxide treatment efficacy was assessed by comparing the percent egg hatch in the treatment group to the untreated control group in each trial. Mean percent hatch in Trial I was 44% (control), 54% (500 mg l(-1)), and 69% (750 mg l(-1)). Hydrogen peroxide treatment at either 500 or 750 mg l(-1) significantly (P<0.01) increased the percent hatch compared to the untreated control group. In Trial 2, hydrogen peroxide treatment at 500 mg l(-1) significantly (P<0.01) increased the percent egg hatch (67%) relative to the untreated controls (57%). Hydrogen peroxide treatment reduced egg mortality and increased the percent hatch of channel catfish eggs regardless of whether eggs were incubated in the gelatinous matrix or without the matrix in comparison to the untreated control. (C) 2004 Elsevier B.V. All rights reserved.

  2. Bioremediation of chlorobenzene-contaminated ground water in an in situ reactor mediated by hydrogen peroxide.

    PubMed

    Vogt, Carsten; Alfreider, Albin; Lorbeer, Helmut; Hoffmann, Doreen; Wuensche, Lothar; Babel, Wolfgang

    2004-01-01

    New in situ reactive barrier technologies were tested nearby a local aquifer in Bitterfeld, Saxonia-Anhalt, Germany, which is polluted mainly by chlorobenzene (CB), in concentrations up to 450 microM. A reactor filled with original aquifer sediment was designed for the microbiological remediation of the ground water by indigenous bacterial communities. Two remediation variants were examined: (a) the degradation of CB under anoxic conditions in the presence of nitrate; (b) the degradation of CB under mixed electron acceptor conditions (oxygen+nitrate) using hydrogen peroxide as the oxygen-releasing compound. Under anoxic conditions, no definite degradation of CB was observed. Adding hydrogen peroxide (2.94 mM) and nitrate (2 mM) led to the disappearance of CB (ca. 150 microM) in the lower part of the reactor, accompanied by a strong increase of the number of cultivable aerobic CB degrading bacteria in reactor water and sediment samples, indicating that CB was degraded mainly by productive bacterial metabolism. Several aerobic CB degrading bacteria, mostly belonging to the genera Pseudomonas and Rhodococcus, were isolated from reactor water and sediments. In laboratory experiments with reactor water, oxygen was rapidly released by hydrogen peroxide, whereas biotic-induced decomposition reactions of hydrogen peroxide were almost four times faster than abiotic-induced decomposition reactions. A clear chemical degradation of CB mediated by hydrogen peroxide was not observed. CB was also completely degraded in the reactor after reducing the hydrogen peroxide concentration to 880 microM. The CB degradation completely collapsed after reducing the hydrogen peroxide concentration to 440 microM. In the following, the hydrogen peroxide concentrations were increased again (to 880 microM, 2.94 mM, and 880 microM, respectively), but the oxygen demand for CB degradation was higher than observed before, indicating a shift in the bacterial population. During the whole experiment

  3. Bleaching effect of activation of hydrogen peroxide using photon-initiated photoacoustic streaming technique.

    PubMed

    Arslan, Hakan; Akcay, Merve; Yasa, Bilal; Hatirli, Huseyin; Saygili, Gökhan

    2015-03-01

    This study aims to investigate the bleaching effectiveness of photon-initiated photoacoustic streaming (PIPS) using 35 % hydrogen peroxide on discolored teeth as compared with different devital bleaching techniques. Fifty extracted human mandibular incisors were collected and artificially stained using sheep's blood. The teeth were then randomly divided into five groups according to the different bleaching procedures to be tested: walking bleach with sodium perborate and with 35 % hydrogen peroxide gel, both for 1 week; PIPS using 35 % hydrogen peroxide liquid for 30 min; and just 35 % hydrogen peroxide, as a liquid and as a gel (again, for 30 min). Spectrophotometric measurements were obtained on the buccal surfaces of the crowns, at the beginning, just after the bleaching procedures had been performed, and the following first, third, and seventh days. The ∆E values were calculated, and the data were analyzed with a two-way analysis of variance (P = 0.05). There were statistically significant differences between the PIPS technique using 35 % hydrogen peroxide liquid and the 35 % hydrogen peroxide liquid and gel without PIPS immediately after the procedures (P < 0.05). On Days 1, 3, and 7, the PIPS technique further bleached specimens more than all of the other techniques (P < 0.05). The PIPS technique using 35 % hydrogen peroxide was found to be more effective than all of the conventional techniques. Within limitations of this study, PIPS technique using hydrogen peroxide was superior to the conventional techniques. Further studies should be conducted to determine if the PIPS technique results in any complications, particularly cervical resorption.

  4. Microbicidal activity of N-chlorotaurine in combination with hydrogen peroxide.

    PubMed

    Mustedanagic, Jasmin; Ximenes, Valdecir Farias; Nagl, Markus

    2017-12-01

    N-chlorotaurine (NCT) and hydrogen peroxide are powerful endogenous antiseptics. In vivo, the reaction between hydrogen peroxide and metal ions leads to the formation of free hydroxyl radicals, which have an increased bactericidal activity. This study examined whether there is an additive antimicrobial effect of NCT combined with hydrogen peroxide. Additionally, it was tested if the additive effect is based on the formation of free radicals. We found by luminometry that, in the presence of H2O2, NCT caused a slow and long-lasting production of singlet oxygen in contrast to HOCl, where this burst occurred instantaneously. Both NCT and hydrogen peroxide (1.0 and 0.1%) demonstrated bactericidal and fungicidal activity. At pH 7.1 and 37 °C, hydrogen peroxide (1%, 294 mM) showed a stronger bactericidal and particularly fungicidal activity than NCT (1%, 55 mM), whereas at pH 4.0 and also in the presence of 5.0% peptone NCT revealed a stronger bactericidal activity. A combination of NCT and hydrogen peroxide led to an increased bactericidal but no increased fungicidal activity compared to both substances alone. The additive effect against bacteria was not removed in the presence of the radical scavengers NaN3, DMSO, or peptone. As a conclusion, NCT and hydrogen peroxide used concurrently interact additive against a range of microorganisms. However, the results of this study suggest that the additive effect of NCT combined with hydrogen peroxide is rather not based on the formation of free radicals.

  5. Strategies for designing supported gold-palladium bimetallic catalysts for the direct synthesis of hydrogen peroxide.

    PubMed

    Edwards, Jennifer K; Freakley, Simon J; Carley, Albert F; Kiely, Christopher J; Hutchings, Graham J

    2014-03-18

    Hydrogen peroxide is a widely used chemical but is not very efficient to make in smaller than industrial scale. It is an important commodity chemical used for bleaching, disinfection, and chemical manufacture. At present, manufacturers use an indirect process in which anthraquinones are sequentially hydrogenated and oxidized in a manner that hydrogen and oxygen are never mixed. However, this process is only economic at a very large scale producing a concentrated product. For many years, the identification of a direct process has been a research goal because it could operate at the point of need, producing hydrogen peroxide at the required concentration for its applications. Research on this topic has been ongoing for about 100 years. Until the last 10 years, catalyst design was solely directed at using supported palladium nanoparticles. These catalysts require the use of bromide and acid to arrest peroxide decomposition, since palladium is a very active catalyst for hydrogen peroxide hydrogenation. Recently, chemists have shown that supported gold nanoparticles are active when gold is alloyed with palladium because this leads to a significant synergistic enhancement in activity and importantly selectivity. Crucially, bimetallic gold-based catalysts do not require the addition of bromide and acids, but with carbon dioxide as a diluent its solubility in the reaction media acts as an in situ acid promoter, which represents a greener approach for peroxide synthesis. The gold catalysts can operate under intrinsically safe conditions using dilute hydrogen and oxygen, yet these catalysts are so active that they can generate peroxide at commercially significant rates. The major problem associated with the direct synthesis of hydrogen peroxide concerns the selectivity of hydrogen usage, since in the indirect process this factor has been finely tuned over decades of operation. In this Account, we discuss how the gold-palladium bimetallic catalysts have active sites for the

  6. Co-operative inhibitory effects of hydrogen peroxide and iodine against bacterial and yeast species

    PubMed Central

    2013-01-01

    Background Hydrogen peroxide and iodine are powerful antimicrobials widely used as antiseptics and disinfectants. Their antimicrobial properties are known to be enhanced by combining them with other compounds. We studied co-operative inhibitory activities (synergism, additive effects and modes of growth inhibition) of hydrogen peroxide and iodine used concurrently against 3 bacterial and 16 yeast species. Results Synergistic or additive inhibitory effects were shown for hydrogen peroxide and iodine mixtures against all 19 species used in the study. Both biocides were mostly cidal individually and in mixtures against Pseudomonas aeruginosa and Staphylococcus aureus. Both compounds manifested static inhibitory effects individually, but their mixtures were synergistically cidal for Saccharomyces cerevisiae and Escherihia coli. Cells of S. cerevisiae treated with hydrogen peroxide and iodine-hydrogen peroxide mixture produced increased numbers of respiratory deficient mutants indicating genotoxic effects. Conclusion Iodine and hydrogen peroxide used concurrently interact synergistically or additively against a range of prokaryotic and eukaryotic microorganisms. The study provides an insight as to how these traditional antimicrobials could be used more effectively for disinfection and antisepsis. In addition, a simple approach is proposed for scoring genotoxicity of different biocides by using the budding yeast system. PMID:23856115

  7. Co-operative inhibitory effects of hydrogen peroxide and iodine against bacterial and yeast species.

    PubMed

    Zubko, Elena I; Zubko, Mikhajlo K

    2013-07-15

    Hydrogen peroxide and iodine are powerful antimicrobials widely used as antiseptics and disinfectants. Their antimicrobial properties are known to be enhanced by combining them with other compounds. We studied co-operative inhibitory activities (synergism, additive effects and modes of growth inhibition) of hydrogen peroxide and iodine used concurrently against 3 bacterial and 16 yeast species. Synergistic or additive inhibitory effects were shown for hydrogen peroxide and iodine mixtures against all 19 species used in the study. Both biocides were mostly cidal individually and in mixtures against Pseudomonas aeruginosa and Staphylococcus aureus. Both compounds manifested static inhibitory effects individually, but their mixtures were synergistically cidal for Saccharomyces cerevisiae and Escherihia coli. Cells of S. cerevisiae treated with hydrogen peroxide and iodine-hydrogen peroxide mixture produced increased numbers of respiratory deficient mutants indicating genotoxic effects. Iodine and hydrogen peroxide used concurrently interact synergistically or additively against a range of prokaryotic and eukaryotic microorganisms. The study provides an insight as to how these traditional antimicrobials could be used more effectively for disinfection and antisepsis. In addition, a simple approach is proposed for scoring genotoxicity of different biocides by using the budding yeast system.

  8. Boronate-based fluorescent probes: imaging hydrogen peroxide in living systems.

    PubMed

    Lin, Vivian S; Dickinson, Bryan C; Chang, Christopher J

    2013-01-01

    Hydrogen peroxide, a reactive oxygen species with unique chemical properties, is produced endogenously in living systems as a destructive oxidant to ward off pathogens or as a finely tuned second messenger in dynamic cellular signaling pathways. In order to understand the complex roles that hydrogen peroxide can play in biological systems, new tools to monitor hydrogen peroxide in its native settings, with high selectivity and sensitivity, are needed. Knowledge of organic synthetic reactivity provides the foundation for the molecular design of selective, functional hydrogen peroxide probes. A palette of fluorescent and luminescent probes that react chemoselectively with hydrogen peroxide has been developed, utilizing a boronate oxidation trigger. These indicators offer a variety of colors and in cellulo characteristics and have been used to examine hydrogen peroxide in a number of experimental setups, including in vitro fluorometry, confocal fluorescence microscopy, and flow cytometry. In this chapter, we provide an overview of the chemical features of these probes and information on their behavior to help researchers select the optimal probe and application. Copyright © 2013 Elsevier Inc. All rights reserved.

  9. Acute toxicity of hydrogen peroxide treatments to selected lifestages of cold-, cool-, and warmwater fish

    USGS Publications Warehouse

    Gaikowski, M.P.; Rach, J.J.; Ramsay, R.T.

    1999-01-01

    Hatchery personnel depend on therapeutant treatments to control diseases. Currently, hatchery managers in the United States are limited to one approved therapeutant (formalin) and three compounds of Low Regulatory Priority (sodium chloride, hydrogen peroxide, and acetic acid) to control external diseases of cultured fish. Hydrogen peroxide has been used to effectively control external columnaris and bacterial gill disease in rainbow trout, however, definitive safe treatment concentrations for hydrogen peroxide are lacking for a variety of species. We report the acute toxicity of hydrogen peroxide treatments to 11 species of fry and 13 species of fingerling freshwater fish. Most mortality occurred within the first 30 h after the first exposure to hydrogen peroxide with little change in the overall shape of survival curves over time. Our data predict that in an actual therapeutic application of hydrogen peroxide, most treatment-related mortalities would be observed shortly after the initial exposure. Coolwater species were more sensitive than coldwater species but were generally similar to warmwater species tested. Based on our mortality data, coldwater species and largemouth bass may be treated for 60 min at concentrations of ??? 150 ??l/l without harmful effects; all muskellunge, walleye, bluegill, channel catfish, yellow perch, pallid sturgeon fingerlings, fathead minnow fingerlings, white sucker fingerlings, and northern pike fry may be treated for 60 min at ??? 100 ??l/l; and northern pike fingerlings and white sucker, yellow perch and fathead minnow fry may be treated for 60 min at ??? 50 ??l/l.

  10. Acute toxicity of hydrogen peroxide treatments to selected lifestages of cold-, cool-, and warmwater fish

    USGS Publications Warehouse

    Gaikowski, Mark P.; Rach, Jeffery J.; Ramsay, Robert T.

    1999-01-01

    Hatchery personnel depend on therapeutant treatments to control diseases. Currently, hatchery managers in the United States are limited to one approved therapeutant (formalin) and three compounds of Low Regulatory Priority (sodium chloride, hydrogen peroxide, and acetic acid) to control external diseases of cultured fish. Hydrogen peroxide has been used to effectively control external columnaris and bacterial gill disease in rainbow trout, however, definitive safe treatment concentrations for hydrogen peroxide are lacking for a variety of species. We report the acute toxicity of hydrogen peroxide treatments to 11 species of fry and 13 species of fingerling freshwater fish. Most mortality occurred within the first 30 h after the first exposure to hydrogen peroxide with little change in the overall shape of survival curves over time. Our data predict that in an actual therapeutic application of hydrogen peroxide, most treatment-related mortalities would be observed shortly after the initial exposure. Coolwater species were more sensitive than coldwater species but were generally similar to warmwater species tested. Based on our mortality data, coldwater species and largemouth bass may be treated for 60 min at concentrations of ≤ 150 (μl/1 without harmful effects; all muskellunge, walleye, bluegill, channel catfish, yellow perch, pallid sturgeon fingerlings, fathead minnow fingerlings, white sucker fingerlings, and northern pike fry may be treated for 60 min at ≤ 100 μl/l; and northern pike fingerlings and white sucker, yellow perch and fathead minnow fry may be treated for 60 min at ≤ 50μl/l.

  11. In situ oxidation remediation technologies: kinetic of hydrogen peroxide decomposition on soil organic matter.

    PubMed

    Romero, Arturo; Santos, Aurora; Vicente, Fernando; Rodriguez, Sergio; Lafuente, A Lopez

    2009-10-30

    Rates of hydrogen peroxide decomposition were investigated in soils slurries. The interaction soil-hydrogen peroxide was studied using a slurry system at 20 degrees C and pH 7. To determine the role of soil organic matter (SOM) in the decomposition of hydrogen peroxide, several experiments were carried out with two soils with different SOM content (S1=15.1%, S2=10%). The influence of the oxidant dosage ([H2O2](o) from 10 to 30 g L(-1) and soil weight to liquid phase volume ratio=500 g L(-1)) was investigated using the two calcareous loamy sand soil samples. The results showed a rate dependency on both SOM and hydrogen peroxide concentration being the H2O2 decomposition rate over soil surface described by a second-order kinetic expression r(H2O2) = -dn(H2O2) / W(SOM) dt = kC(H2O2) C(SOM). Thermogravimetric analysis (TGA) was used to evaluate the effect caused by the application of this oxidant on the SOM content. It was found a slightly increase of SOM content after treatment with hydrogen peroxide, probably due to the incorporation of oxygen from the oxidant (hydrogen peroxide).

  12. Role of high-energy phosphate metabolism in hydrogen peroxide-induced cardiac dysfunction.

    PubMed

    Matsumoto, Y; Kaneko, M; Iimuro, M; Fujise, Y; Hayashi, H

    2000-01-01

    This study was undertaken to clarify the role of high-energy phosphate metabolism in hydrogen peroxide-induced cardiac dysfunction using phosphorus and fluorine nuclear magnetic resonance spectroscopy. The exposure of a Langendorff-perfused heart to hydrogen peroxide (200-400 micromol/L, 8 min) provoked biphasic contractile dysfunction characterized by a transient depression of left ventricular developed pressure during the administration of hydrogen peroxide and a delayed elevation of left ventricular end-diastolic pressure after the washout of hydrogen peroxide. The initial phase of cardiac dysfunction correlated well with the accumulation of sugar phosphates (r = 0.89, p < 0.01). Furthermore, we demonstrated that glibenclamide, a potent inhibitor of the ATP-sensitive K+ channel, attenuated the initial depression of developed pressure. On the other hand, the delayed elevation of end-diastolic pressure correlated well with the total ATP depletion (r = 0.96, p < 0.01). However, ATP loss was supposed to be a mere result from the increased ATP consumption corresponding to a rise in intracellular free Ca2+ (from the control value of 315+/-23 nmol/L to 708+/-104 after the administration of hydrogen peroxide, p < 0.01), which also paralleled the elevation of end-diastolic pressure. Thus glycolytic inhibition and intracellular Ca2+ overload are independently responsible for the biphasic contractile dysfunction induced by hydrogen peroxide.

  13. Optimization of hydrogen peroxide in totally chlorine free bleaching of cellulose pulp from olive tree residues.

    PubMed

    López, F; Díaz, M J; Eugenio, M E; Ariza, J; Rodríguez, A; Jiménez, L

    2003-05-01

    The influence of the operating conditions used in the bleaching of olive wood trimmings pulp (viz. hydrogen peroxide concentration and time) on the yield, kappa index and viscosity of the resulting pulp and on strength-related properties of paper sheets was studied to determine the optimal bleaching conditions of this pulp. Hydrogen peroxide bleached pulps at different sequences (oxygen, ozone, chlorine dioxide and alkaline extractions) were compared. Hydrogen peroxide bleaching proved to be suitable for this pulp. Considerable improvements in viscosity were obtained with respect to other bleaching sequences such as oxygen, ozone and chlorine dioxide. Hydrogen peroxide bleaching decreased the kappa index 51.3% less than ozone bleaching, 25.0% less than chlorine dioxide (D) and 6.3% less combined chlorine dioxide-alkaline extraction (DE). To obtain kappa indices 50.9% and 37.9% lower than the index achieved by hydrogen peroxide, oxygen (LaO(p)) and ozone (LaO(LaZ)R) sequences respectively were needed. Lower-medium levels of hydrogen peroxide concentrations (1-3%) and high reaction times (210 min) proved to be suitable for bleaching of pulp olive trimming residues. This approach could be used on this residue to produce adequately bleached pulp.

  14. Doxorubicin increases intracellular hydrogen peroxide in PC3 prostate cancer cells

    PubMed Central

    Wagner, Brett A.; Evig, Crystal B.; Reszka, Krzysztof J.; Buettner, Garry R.; Burns, C. Patrick

    2015-01-01

    We studied the effect of doxorubicin on the production of hydrogen peroxide by PC3 human prostate cancer cells, using a sensitive assay based on aminotriazole-mediated inhibition of catalase. PC3 cells exposed to increasing concentrations of doxorubicin had an increase in intracellular hydrogen peroxide that was concentration-dependent up to 1 μM doxorubicin. The apparent hydrogen peroxide concentration in the PC3 cells was 13 ± 4 pM under basal steady-state conditions and increased to 51 ± 13 pM after exposure to 1 μM doxorubicin for 30 min. The level of hydrogen peroxide in the medium as measured by Amplex Red did not increase as a result of doxorubicin treatment. PC3 cells overexpressing catalase were no more resistant to doxorubicin cytotoxicity as compared to non-transduced wild-type cells; therefore, the exact role of hydrogen peroxide in anthracycline cytotoxicity remains unproven. This study demonstrates that a specific oxidative event associated with the exposure of PC3 human prostate cancer cells to anthracyclines results in an increase in intracellular hydrogen peroxide. PMID:16054588

  15. Photosynthetic electron flow to oxygen and diffusion of hydrogen peroxide through the chloroplast envelope via aquaporins.

    PubMed

    Mubarakshina Borisova, Maria M; Kozuleva, Marina A; Rudenko, Natalia N; Naydov, Ilya A; Klenina, Irina B; Ivanov, Boris N

    2012-08-01

    Light-induced generation of superoxide radicals and hydrogen peroxide in isolated thylakoids has been studied with a lipophilic spin probe, cyclic hydroxylamine 1-hydroxy-4-isobutyramido-2,2,6,6-tetramethylpiperidinium (TMT-H) to detect superoxide radicals, and the spin trap α-(4-pyridyl-1-oxide)-N-tert-butylnitron (4-POBN) to detect hydrogen peroxide-derived hydroxyl radicals. Accumulation of the radical products of the above reactions has been followed using electron paramagnetic resonance. It is found that the increased production of superoxide radicals and hydrogen peroxide in higher light is due to the enhanced production of these species within the thylakoid membrane, rather than outside the membrane. Fluorescent probe Amplex red, which forms fluorescent product, resorufin, in the reaction with hydrogen peroxide, has been used to detect hydrogen peroxide outside isolated chloroplasts using confocal microscopy. Resorufin fluorescence outside the chloroplasts is found to be suppressed by 60% in the presence of the inhibitor of aquaporins, acetazolamide (AZA), indicating that hydrogen peroxide can diffuse through the chloroplast envelope aquaporins. It is demonstrated that AZA also inhibits carbonic anhydrase activity of the isolated envelope. We put forward a hypothesis that carbonic anhydrase presumably can be attached to the envelope aquaporins. This article is part of a Special Issue entitled: Photosynthesis Research for Sustainability: from Natural to Artificial. Copyright © 2012 Elsevier B.V. All rights reserved.

  16. Can an LED-laser hybrid light help to decrease hydrogen peroxide concentration while maintaining effectiveness in teeth bleaching?

    NASA Astrophysics Data System (ADS)

    Martín, J.; Ovies, N.; Cisternas, P.; Fernández, E.; Oliveira Junior, O. B.; de Andrade, M. F.; Moncada, G.; Vildósola, P.

    2015-02-01

    The aim of this study was to compare the bleaching efficacy of 35% hydrogen peroxide and 15% hydrogen peroxide with nitrogen-doped titanium dioxide catalysed by an LED-laser hybrid light. We studied 70 patients randomized to two groups. Tooth shade and pulpal sensitivity were registered. Group 1: 15% hydrogen peroxide with nitrogen-doped titanium dioxide. Group 2: 35% hydrogen peroxide. Both groups were activated by an LED-laser light. No significant differences were seen in shade change immediately, one week or one month after treatment (p > 0.05). Differences were seen in pulpal sensitivity (p < 0.05). The use of an LED-laser hybrid light to activate 15% hydrogen peroxide gel with N_TiO2 permits decreasing the peroxide concentration with similar aesthetic results and less pulpal sensitivity than using 35% hydrogen peroxide for bleaching teeth.

  17. Salinity-gradient energy driven microbial electrosynthesis of hydrogen peroxide

    NASA Astrophysics Data System (ADS)

    Li, Xiaohu; Angelidaki, Irini; Zhang, Yifeng

    2017-02-01

    Hydrogen peroxide (H2O2) as a strong oxidant, is widely used in various chemical industries and environmental remediation processes. In this study, we developed an innovative method for cost-effective production of H2O2 by using a microbial reverse-electrodialysis electrolysis cell (MREC). In the MREC, electrical potential generated by the exoelectrogens and the salinity-gradient between salt and fresh water were utilized to drive the high-rate H2O2 production. Operational parameters such as air flow rate, pH, cathodic potential, flow rate of salt and fresh water were investigated. The optimal H2O2 production was observed at salt and fresh water flow rate of 0.5 mL min-1, air flow rate of 12-20 mL min-1, cathode potential of -0.485 ± 0.025 V (vs Ag/AgCl). The maximum H2O2 accumulated concentration of 778 ± 11 mg L-1 was obtained at corresponding production rate of 11.5 ± 0.5 mg L-1 h-1. The overall energy input for the synthesis process was 0.45 ± 0.03 kWh kg-1 H2O2. Cathode potential was the key factor for H2O2 production, which was mainly affected by the air flow rate. This work for the first time proved the potential of MREC as an efficient platform technology for simultaneous electrosynthesis of valuable chemicals and utilization of salinity-gradient energy.

  18. Shock initiation studies on high concentration hydrogen peroxide

    SciTech Connect

    Sheffield, Stephen A; Dattelbaum, Dana M; Stahl, David B; Gibson, L. Lee; Bartram, Brian D.

    2009-01-01

    Concentrated hydrogen peroxide (H{sub 2}O{sub 2}) has been known to detonate for many years. However, because of its reactivity and the difficulty in handling and confining it, along with the large critical diameter, few studies providing basic information about the initiation and detonation properties have been published. We are conducting a study to understand and quantify the initiation and detonation properties of highly concentrated H{sub 2}O{sub 2} using a gas-driven two-stage gun to produce well defined shock inputs. Multiple magnetic gauges are used to make in-situ measurements of the growth of reaction and subsequent detonation in the liquid. These experiments are designed to be one-dimensional to eliminate any difficulties that might be encountered with large critical diameters. Because of the concern of the reactivity of the H{sub 2}O{sub 2} with the confining materials, a remote loading system has been developed. The gun is pressurized, then the cell is filled and the experiment shot within less than three minutes. TV cameras are attached to the target so the cell filling can be monitored. Several experiments have been completed on {approx}98 wt % H{sub 2}O{sub 2}/H{sub 2}O mixtures; initiation has been observed in some experiments that shows homogeneous shock initiation behavior. The initial shock pressurizes and heats the mixture. After an induction time, a thermal explosion type reaction produces an evolving reactive wave that strengthens and eventually overdrives the first wave producing a detonation. From these measurements, we have determined unreacted Hugoniot information, times (distances) to detonation (Pop-plot points) that indicate low sensitivity, and detonation velocities of high concentration H{sub 2}O{sub 2}/H{sub 2}O solutions that agree with earlier estimates.

  19. Pyruvate protects neurons against hydrogen peroxide-induced toxicity.

    PubMed

    Desagher, S; Glowinski, J; Prémont, J

    1997-12-01

    Hydrogen peroxide (H2O2) is suspected to be involved in numerous brain pathologies such as neurodegenerative diseases or in acute injury such as ischemia or trauma. In this study, we examined the ability of pyruvate to improve the survival of cultured striatal neurons exposed for 30 min to H2O2, as estimated 24 hr later by the 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazoliumbromide assay. Pyruvate strongly protected neurons against both H2O2 added to the external medium and H2O2 endogenously produced through the redox cycling of the experimental quinone menadione. The neuroprotective effect of pyruvate appeared to result rather from the ability of alpha-ketoacids to undergo nonenzymatic decarboxylation in the presence of H2O2 than from an improvement of energy metabolism. Indeed, several other alpha-ketoacids, including alpha-ketobutyrate, which is not an energy substrate, reproduced the neuroprotective effect of pyruvate. In contrast, lactate, a neuronal energy substrate, did not protect neurons from H2O2. Optimal neuroprotection was achieved with relatively low concentrations of pyruvate (

  20. Hydrogen peroxide induces apoptosis via a mitochondrial pathway in chondrocytes

    NASA Astrophysics Data System (ADS)

    Zhuang, Cai-ping; Liang, Qian; Wang, Xiao-ping; Chen, Tong-sheng

    2012-03-01

    The degenerative joint disease such as osteoarthritis (OA) is closely associated with the death of chondrocytes in apoptosis fashion. Hydrogen peroxide (H2O2), higher expression following acute damage in OA patients, has been shown to be up-regulated during apoptosis in a bulk of experimental models. This study was aimed to explore the mechanism of H2O2-induced rabbit chondrocytes apoptosis. Articular cartilage was biopsied from the joints of 6 weeks old New Zealand rabbits. Cell Counting Kit (CCK-8) assay was used to assess the inhibitory effect of H2O2 on cell viability. H2O2 treatment induced a remarkable reduction of cell viability. We used flow cytometry to assess the form of cell death with Annexin-V/PI double staining, and found that H2O2 treatment induced apoptosis in a dose-and time-dependent manner. Exposure of chondrocytes to 1.5 mM of H2O2 for 2 h induced a burst apoptosis that can be alleviated by N-acetyl cysteine (NAC) pretreatment, an anti-oxidant amino-acid derivative. Loss of mitochondria membrane potential (▵Ψm) was evaluated using confocal microscopy imaging and flow cytometry (FCM). H2O2 treatment induced a marked reduction of ▵Ψm, and the abrupt disappearance of ▵Ψm occurred within 5 minutes. These results indicate that H2O2 induces a rapid apoptosis via a mitochondrial pathway in rabbit chondrocytes.

  1. Hydrogen peroxide regulated photosynthesis in C4-pepc transgenic rice.

    PubMed

    Ren, C G; Li, X; Liu, X L; Wei, X D; Dai, C C

    2014-01-01

    In this study, we investigated the photosynthetic physiological basis in 'PC' transgenic rice (Oryza sativa L.), showing high-level expression of the gene encoding C4 phosphoenolpyruvate carboxylase (pepc), by hydrogen peroxide (H2O2). The C4-PEPC gene (pepc) from maize in the transgenic rice plants was checked by PCR. Comparison of yield components and photosynthetic indices between PC and untransformed wild-type (WT) plants indicated that increased yield in PC was associated with higher net photosynthetic rate and higher activities of phosphoenolpyruvate carboxylase (PEPC). Both PC and WT plants were treated with 1 mmol L(-1) abscisic acid (ABA), 0.04% 1-butanol (BA), 2 mmol L(-1) neomycin (NS), or 2 mmol L(-1) diphenyleneiodonium chloride (DPI) to investigate the relationship between photosynthesis and levels of H2O2 and phosphatidic acid. In both PC and WT, ABA induced H2O2 generation and simultaneous decrease in stomatal conductance (g(s)). PC plants treated with BA showed decreased H2O2 content and strongly increased g(s) within 2 h of treatment. Similar results were observed in response to DPI treatment in PC. However, WT did not observe the decrease of H2O2 during the treatments of BA and DPI. The reduced H2O2 content in PC caused by BA treatment differed to that induced by DPI because BA did not inhibit NADPH oxidase activities. While BA induced a larger PEPC activity in PC, and higher catalase activity as well. These results indicated that the regulation of endogenous H2O2 metabolism of PC could be helpful for enhancing photosynthetic capability. Copyright © 2013 Elsevier Masson SAS. All rights reserved.

  2. Impairment of phagocytic functions of alveolar macrophages by hydrogen peroxide

    SciTech Connect

    Oosting, R.S.; van Bree, L.; van Iwaarden, J.F.; van Golde, L.M.; Verhoef, J. )

    1990-08-01

    Hydrogen peroxide (H2O2) inhibited phagocytosis and superoxide anion production by rat alveolar macrophages. The inhibition was irreversible and concentration and exposure time dependent. The potential relationship between H2O2-induced biochemical perturbations and impaired alveolar macrophage phagocytic functions was investigated. Alveolar macrophage viability and Fc receptor binding capacity were not affected by H2O2. There was probably no correlation between a H2O2-induced rise in cytosolic (Ca2+) ((Ca2+)i) and the impairment of phagocytosis by alveolar macrophages, as was suggested by the following findings. First, the H2O2-induced rise in (Ca2+)i could be inhibited by chelation of extracellular Ca2+, whereas the H2O2-induced impairment of phagocytosis could not. Second, the H2O2-induced rise in (Ca2+)i was reversible, whereas the impairment of phagocytosis was not. And finally, a rise in (Ca2+)i by incubation of alveolar macrophages with the calcium ionophore A23187 did not affect phagocytosis. Various experiments suggested that ATP depletion may play an important role in the H2O2 toxicity for alveolar macrophages. Comparable concentrations of H2O2 caused an irreversible decrease both in cellular ATP and in phagocytosis and superoxide production by alveolar macrophages. In addition, time course of ATP depletion and induction of impaired alveolar macrophage function were similar. In view of the fact that the strong oxidant H2O2 may react with a large variety of biological substances, possible other toxic lesions may not be excluded as underlying mechanism for H2O2-induced inhibition of phagocytic functions of alveolar macrophages.

  3. Hydrogen peroxide spraying alleviates drought stress in soybean plants.

    PubMed

    Ishibashi, Yushi; Yamaguchi, Haruka; Yuasa, Takashi; Iwaya-Inoue, Mari; Arima, Susumu; Zheng, Shao-Hui

    2011-09-01

    To ascertain the effect of exogenously applied hydrogen peroxide (H2O2) on drought stress, we examined whether the spraying of soybean leaves with H2O2 would alleviate the symptoms of drought stress. Pre-treatment by spraying leaves with H2O2 delayed foliar wilting caused by drought stress compared to leaves sprayed with distilled water (DW). Additionally, the relative water content of drought-stressed leaves pre-treated with H2O2 was higher than that of leaves pre-treated with DW. Therefore, we analyzed the effect of H2O2 spraying on photosynthetic parameters and on the biosynthesis of oligosaccharides related to water retention in leaves during drought stress. Under conditions of drought stress, the net photosynthetic rate and stomatal conductance of leaves pre-treated with H2O2 were higher than those of leaves pre-treated with DW. In contrast to DW spraying, H2O2 spraying immediately caused an increase in the mRNA levels of d-myo-inositol 3-phosphate synthase 2 (GmMIPS2) and galactinol synthase (GolS), which encode key enzymes for the biosynthesis of oligosaccharides known to help plants tolerate drought stress. In addition, the levels of myo-inositol and galactinol were higher in H2O2-treated leaves than in DW-treated leaves. These results indicated that H2O2 spraying enabled the soybean plant to avoid drought stress through the maintenance of leaf water content, and that this water retention was caused by the promotion of oligosaccharide biosynthesis rather than by rapid stomatal closure. Copyright © 2011 Elsevier GmbH. All rights reserved.

  4. Aquaporin-facilitated transmembrane diffusion of hydrogen peroxide.

    PubMed

    Bienert, Gerd P; Chaumont, François

    2014-05-01

    Hydrogen peroxide (H2O2) is an important signaling compound that has recently been identified as a new substrate for several members of the aquaporin superfamily in various organisms. Evidence is emerging about the physiological significance of aquaporin-facilitated H2O2 diffusion. This review summarizes current knowledge about aquaporin-facilitated H2O2 diffusion across cellular membranes. It focuses on physicochemical and experimental evidence demonstrating the involvement of aquaporins in the transport of this redox signaling compound and discusses the regulation and structural prerequisites of these channels to transmit this signal. It also provides perspectives about the potential importance of aquaporin-facilitated H2O2 diffusion processes and places this knowledge in the context of the current understanding of transmembrane redox signaling processes. Specific aquaporin isoforms facilitate the passive diffusion of H2O2 across biological membranes and control H2O2 membrane permeability and signaling in living organisms. Redox signaling is a very important process regulating the physiology of cells and organisms in a similar way to the well-characterized hormonal and calcium signaling pathways. Efficient transmembrane diffusion of H2O2, a key molecule in the redox signaling network, requires aquaporins and makes these channels important players in this signaling process. Channel-mediated membrane transport allows the fine adjustment of H2O2 levels in the cytoplasm, intracellular organelles, the apoplast, and the extracellular space, which are essential for it to function as a signal molecule. This article is part of a Special Issue entitled Aquaporins. © 2013.

  5. Hydrogen peroxide diffusion with and without light activation.

    PubMed

    Llena, Carmen; Forner, Leopoldo; Vazquez, María

    The aim of this study was to assess the dental bleaching efficacy of 37.5% hydrogen peroxide (HP), with and without light activation, in HP-exposed and unexposed areas. 28 bovine teeth were selected and divided into two groups (n = 14). Crowns were detached and stained with tea. The gingival half was covered with a gingival barrier. In the incisal half, 37.5% HP (Pola Office+, SDI) was applied three times, with a 1-week interval between applications. In HP-A group, the bleaching agent was activated for 3 min with a LED lamp. No light activation was applied in HP-N group. Dental color variation was determined through a spectrophotometer in both halves. Statistical analysis between groups was performed with an ANOVA test, and intragroup differences were evaluated, with an ANOVA test for paired data, with a significance level of P < 0.05. An increase in lightness and a decrease in chroma were found in both groups and halves. No significant differences in ΔE between groups (P > 0.5) were detected in the incisal half. After treatment, a significantly higher ΔE was found in the gingival half for HP-A group (P < 0.05). For the same group, a significantly higher bleaching effect was found in the gingival half, compared with the incisal half (P < 0.05). LED activation did not have a significant effect in terms of bleaching in the incisal half, but increased clearance in the gingival half. HP light activation does not significantly increase the whitening effect, but it can improve the bleaching diffusion to areas where it has not been directly applied.

  6. Effects of Hydrogen Peroxide on Coral Photosynthesis and Calcification

    NASA Astrophysics Data System (ADS)

    Higuchi, T.; Fujimura, H.; Arakaki, T.; Oomori, T.

    2007-12-01

    The widely-observed decline of coral reefs is considered to be caused by changes in the environment by natural and anthropogenic activities. As one important factor, the run-off of various matters from human activities to the coastal seawater poses stresses to the corals by degrading the quality of the seawater. In Okinawa, Japan, red- soil running off from the developed land has been a major environmental issue since 1980s. Hydrogen peroxide (HOOH), a strong active oxygen species, is one of the photochemically formed chemicals in the red-soil-polluted seawater. Recent photochemical studies of seawater showed that HOOH photo-formation was faster in the red- soil-polluted seawater than clean seawater. We studied the effects of HOOH on corals by studying the changes in coral carbon metabolisms such as photosynthesis and calcification, which are indicators of the physiological state of a coral colony. The corals were exposed to various concentrations of HOOH (0, 0.3, 3 μM). Two massive coral species of Porites sp. and Goniastrea aspera and one branch coral of Galaxea facicularis were used for the exposure experiments. The control experiments showed that when no HOOH was added, metabolisms of each coral colony were relatively stable. On the other hand, when HOOH was added to the seawater, we observed obvious changes in the coral metabolisms in all the coral species. When 0.3 μM HOOH was added, photosynthesis decreased by 14% and calcification decreased by 17% within 3 days, compared with the control. When 3 μM HOOH was added, photosynthesis decreased by 21% and calcification decreased by 41% within 3 days, compared with the control. Our study showed that higher concentrations of HOOH posed more stress to the coral colonies.

  7. Geranylgeranylacetone suppresses hydrogen peroxide-induced apoptosis of osteoarthritic chondrocytes.

    PubMed

    Yoda, Masaki; Sakai, Tadahiro; Mitsuyama, Hirohito; Hiraiwa, Hideki; Ishiguro, Naoki

    2011-11-01

    Osteoarthritis (OA) is a common disease, afflicting many sufferers with both pain and functional disorders. Various therapies have been attempted for OA, but no fully effective treatment has been established yet. Apoptosis of chondrocytes caused by reactive oxygen species (ROS) has been considered important in the pathogenesis of OA. The progression of OA may be prevented by suppressing apoptosis of chondrocytes. Geranylgeranylacetone (GGA) has been used as an anti-ulcer drug in Japan for more than 20 years. Several recent studies have shown that GGA can induce heat shock protein (HSP) and exert cytoprotective actions on a large variety of cells and tissues. In this study, we investigated the effects of GGA on the apoptosis of OA chondrocytes induced by hydrogen peroxide (H(2)O(2)). Human isolated OA chondrocytes were cultured in the absence or presence of GGA. Cell viability, caspase 3/7 and 9 activities, HSP70 mRNA and protein expressions were examined, and morphological analyses were conducted after exposure of cells to H(2)O(2) to induce apoptosis. Geranylgeranylacetone dose-dependently reversed the H(2)O(2)-induced decrease in cell viability. It was recognized that GGA rendered OA chondrocytes resistant to H(2)O(2)-induced apoptosis from Hoechst 33342 staining and TUNEL staining. Caspases 3 and 9 were activated by addition of H(2)O(2), and GGA suppressed this H(2)O(2)-induced activation of both caspases. H(2)O(2)-induced induction of HSP70 was enhanced in OA chondrocytes by pretreatment with GGA. The results showed that GGA can suppress apoptosis of chondrocytes and enhance production of HSP70. This study is the first, to our knowledge, to demonstrate that GGA protects OA chondrocytes from H(2)O(2)-induced apoptosis, at least in part by enhancing HSP70 production. These results indicate that GGA is a potentially useful drug for the treatment of OA.

  8. Modular advanced oxidation process enabled by cathodic hydrogen peroxide production.

    PubMed

    Barazesh, James M; Hennebel, Tom; Jasper, Justin T; Sedlak, David L

    2015-06-16

    Hydrogen peroxide (H2O2) is frequently used in combination with ultraviolet (UV) light to treat trace organic contaminants in advanced oxidation processes (AOPs). In small-scale applications, such as wellhead and point-of-entry water treatment systems, the need to maintain a stock solution of concentrated H2O2 increases the operational cost and complicates the operation of AOPs. To avoid the need for replenishing a stock solution of H2O2, a gas diffusion electrode was used to generate low concentrations of H2O2 directly in the water prior to its exposure to UV light. Following the AOP, the solution was passed through an anodic chamber to lower the solution pH and remove the residual H2O2. The effectiveness of the technology was evaluated using a suite of trace contaminants that spanned a range of reactivity with UV light and hydroxyl radical (HO(•)) in three different types of source waters (i.e., simulated groundwater, simulated surface water, and municipal wastewater effluent) as well as a sodium chloride solution. Irrespective of the source water, the system produced enough H2O2 to treat up to 120 L water d(-1). The extent of transformation of trace organic contaminants was affected by the current density and the concentrations of HO(•) scavengers in the source water. The electrical energy per order (EEO) ranged from 1 to 3 kWh m(-3), with the UV lamp accounting for most of the energy consumption. The gas diffusion electrode exhibited high efficiency for H2O2 production over extended periods and did not show a diminution in performance in any of the matrices.

  9. Modular Advanced Oxidation Process Enabled by Cathodic Hydrogen Peroxide Production

    PubMed Central

    2015-01-01

    Hydrogen peroxide (H2O2) is frequently used in combination with ultraviolet (UV) light to treat trace organic contaminants in advanced oxidation processes (AOPs). In small-scale applications, such as wellhead and point-of-entry water treatment systems, the need to maintain a stock solution of concentrated H2O2 increases the operational cost and complicates the operation of AOPs. To avoid the need for replenishing a stock solution of H2O2, a gas diffusion electrode was used to generate low concentrations of H2O2 directly in the water prior to its exposure to UV light. Following the AOP, the solution was passed through an anodic chamber to lower the solution pH and remove the residual H2O2. The effectiveness of the technology was evaluated using a suite of trace contaminants that spanned a range of reactivity with UV light and hydroxyl radical (HO•) in three different types of source waters (i.e., simulated groundwater, simulated surface water, and municipal wastewater effluent) as well as a sodium chloride solution. Irrespective of the source water, the system produced enough H2O2 to treat up to 120 L water d–1. The extent of transformation of trace organic contaminants was affected by the current density and the concentrations of HO• scavengers in the source water. The electrical energy per order (EEO) ranged from 1 to 3 kWh m–3, with the UV lamp accounting for most of the energy consumption. The gas diffusion electrode exhibited high efficiency for H2O2 production over extended periods and did not show a diminution in performance in any of the matrices. PMID:26039560

  10. Clinical evaluation of a novel dental whitening lamp and light-catalyzed peroxide gel.

    PubMed

    Ziemba, Steven L; Felix, Heather; MacDonald, Jeffrey; Ward, Marilyn

    2005-01-01

    This study examined whether an ultraviolet light enhanced the whitening efficacy of a peroxide gel containing a photo-Fenton activator. Fifty subjects were enrolled into the trial at two geographically separate sites. As directed by the randomization keys, teeth of half of the study subjects were concurrently exposed to the whitening lamp, while the gel was on their teeth, for a total light exposure of 45 minutes. The other half of the subjects received no light treatment. At each examination, clinical data were collected on the gingival index, shade score, and self-assessed dentinal hypersensitivity. Changes in tooth shade were significantly better (approximately 26% improvement; p < 0.05) for subjects exposed to the gel and dental whitening lamp (average = 7.7 shade changes) compared to subjects exposed to the gel only (average 6.1 shades) immediately after treatment. No reports of erythema, desquamation, ulceration of soft tissues, gross changes in teeth, gingiva, or restorations were documented. The relative changes in mean sensitivity scores were similar for both groups, with no significant differences between the Light and No-light groups at any interval. The whitening effect was improved by approximately 26% when the Zoom2 dental whitening lamp was used. It was demonstrated that the a photo-Fenton activator used with a bleaching light and 20% hydrogen peroxide gel is safe and effective for whitening teeth rapidly.

  11. Considerations for Storage of High Test Hydrogen Peroxide (HTP) Utilizing Non-Metal Containers

    NASA Technical Reports Server (NTRS)

    Moore, Robin E.; Scott, Joseph P.; Wise, Harry

    2005-01-01

    When working with high concentrations of hydrogen peroxide, it is critical that the storage container be constructed of the proper materials, those which will not degrade to the extent that container breakdown or dangerous decomposition occurs. It has been suggested that the only materials that will safely contain the peroxide for a significant period of time are metals of stainless steel construction or aluminum use as High Test Hydrogen Peroxide (HTP) Containers. The stability and decomposition of HTP will be also discussed as well as various means suggested in the literature to minimize these problems. The dangers of excess oxygen generation are also touched upon.

  12. Considerations for Storage of High Test Hydrogen Peroxide (HTP) Utilizing Non-Metal Containers

    NASA Technical Reports Server (NTRS)

    Moore, Robin E.; Scott, Joseph P.; Wise, Harry

    2005-01-01

    When working with high concentrations of hydrogen peroxide, it is critical that the storage container be constructed of the proper materials, those which will not degrade to the extent that container breakdown or dangerous decomposition occurs. It has been suggested that the only materials that will safely contain the peroxide for a significant period of time are metals of stainless steel construction or aluminum use as High Test Hydrogen Peroxide (HTP) Containers. The stability and decomposition of HTP will be also discussed as well as various means suggested in the literature to minimize these problems. The dangers of excess oxygen generation are also touched upon.

  13. Caffeic acid protects hydrogen peroxide induced cell damage in WI-38 human lung fibroblast cells.

    PubMed

    Kang, Kyoung Ah; Lee, Kyoung Hwa; Zhang, Rui; Piao, Meijing; Chae, Sungwook; Kim, Kil Nam; Jeon, You Jin; Park, Doek Bae; You, Ho Jin; Kim, Jin Sook; Hyun, Jin Won

    2006-09-01

    Cytoprotective effect of caffeic acid (3,4-dihydroxy cinnamic acid) on human lung fibroblast (WI-38) cells against hydrogen peroxide induced damage was investigated. Caffeic acid was found to scavenge intracellular reactive oxygen species, and 1,1-diphenyl-2-picrylhydrazyl radical, and thus prevented lipid peroxidation. The caffeic acid protected cell damage of WI-38 cells exposed to hydrogen peroxide (H(2)O(2)), via the activation of extracellular signal regulated kinase protein. Caffeic acid increased the activity of catalase and its protein expression. Hence, from the present study, it is suggestive that caffeic acid protects WI-38 cells against H2O2 damage by enhancing the cellular antioxidant activity.

  14. Iron chlorin e6 scavenges hydroxyl radical and protects human endothelial cells against hydrogen peroxide toxicity.

    PubMed

    Yu, J W; Yoon, S S; Yang, R

    2001-09-01

    Iron chlorin e6 (FeCe6) has recently been proposed to be potentially antimutagenic and antioxidative. However, the antioxidant property of FeCe6 has not been elucidated in detail. In this study, we investigated the ability of FeCe6 to scavenge hydroxyl radical and to protect biomolecules and mammalian cells from oxidative stress-mediated damage. In electron spin resonance (ESR) experiments, FeCe6 showed excellent hydroxyl radical scavenging activity, whereas its iron-deficient molecule, chlorin e6 (Ce6) showed little effect. FeCe6 also significantly reduced hydroxyl radical-induced thiobarbituric acid reactive substance (TBARS) formation and benzoate hydroxylation in a dose-dependent manner. The rate constant for reaction between FeCe6 and hydroxyl radical was measured as 8.5 x 10(10) M(-1) s(-1) by deoxyribose degradation method, and this value was much higher than that of most hydroxyl radical scavengers. Superoxide dismutase (SOD) activity of FeCe6 was also confirmed by ESR study and cytochrome c reduction assay, but its in vitro activity appeared to be less efficient in comparison with other well-known SOD mimics. In addition, FeCe6 appreciably diminished hydroxyl radical-induced DNA single-strand breakage and protein degradation in Fe-catalyzed and Cu-catalyzed Fenton systems, and it significantly protected human endothelial cells against hydrogen peroxide (H2O2) toxicity. These results suggest that FeCe6 is a novel hydroxyl radical scavenger and may be useful for preventing oxidative injury in biological systems.

  15. Direct synthesis of hydrogen peroxide using in-situ selective layer

    NASA Astrophysics Data System (ADS)

    Makertihartha, I. G. B. N.; Dharmawijaya, P. T.; Zunita, M.; Wenten, I. G.

    2017-05-01

    Hydrogen peroxide is used in broad range of application such as oxidation, bleaching, and wastewater treatment. Conventionally, hydrogen peroxide is synthesized using reduction oxidation cycle of anthraquinones from hydrogen and oxygen. This process is rather complex and requires considerable amount of energy. Direct synthesis of hydrogen peroxide is one attractive approach to said problems. However, activity and selectivity is the main problem of direct synthesis since the reactants form explosive mixture. Dilution of gasses is commonly used to solve said problem but limit the amount of reactants in the liquid solvent. Membrane reactor can separate pure reactant gases and also constantly feed them over the length of reaction channel. Pd-Ag alloy membrane can be used both as a catalyst and hydrogen dosage. There are some studies that investigate the use of Pd based membrane reactor but still no commercial application. This paper will bring basic concept of Pd based membrane reactor for direct synthesis of hydrogen peroxide. Special attention will be given to current hurdles and their possible solutions that lead to facile production of hydrogen peroxide. Furthermore, recent trends towards utilization of micro reactor will also be discussed.

  16. Amperometric hydrogen peroxide and glucose biosensor based on NiFe2/ordered mesoporous carbon nanocomposites.

    PubMed

    Xiang, Dong; Yin, Longwei; Ma, Jingyun; Guo, Enyan; Li, Qun; Li, Zhaoqiang; Liu, Kegao

    2015-01-21

    Nanocomposites of NiFex embedded in ordered mesoporous carbon (OMC) (x = 0, 1, 2) were prepared by a wet impregnation and hydrogen reduction process and were used to construct electrochemical biosensors for the amperometric detection of hydrogen peroxide (H2O2) or glucose. The NiFe2/OMC nanocomposites were demonstrated to have a large surface area, suitable mesoporous channels, many edge-plane-like defective sites, and a good distribution of alloyed nanoparticles. The NiFe2/OMC and Nafion modified glass carbon electrode (GCE) exhibited excellent electrocatalytic activities toward the reduction of H2O2 as well. By utilizing it as a bioplatform, GOx (glucose oxidase) cross-linked with Nafion was immobilized on the surface of the electrode for the construction of an amperometric glucose biosensor. Our results indicated that the amperometric hydrogen peroxide biosensor (NiFe2/OMC + Nafion + GCE) showed good analytical performances in term of a high sensitivity of 4.29 μA mM(-1) cm(-2), wide linearity from 6.2 to 42,710 μM and a low detection limit of 0.24 μM at a signal-to-noise ratio of 3 (S/N = 3). This biosensor exhibited excellent selectivity, high stability and negligible interference for the detection of H2O2. In addition, the immobilized enzyme on NiFe2/OMC + Nafion + GCE, retaining its bioactivity, exhibited a reversible two-proton and two-electron transfer reaction, a fast heterogeneous electron transfer rate and an effective Michaelis-Menten constant (K) (3.18 mM). The GOx + NiFe2/OMC + Nafion + GCE could be used to detect glucose based on the oxidation of glucose catalyzed by GOx and exhibited a wide detection range of 48.6-12,500 μM with a high sensitivity of 6.9 μA mM(-1) cm(-2) and a low detection limit of 2.7 μM (S/N = 3). The enzymic biosensor maintained a high selectivity and stability features, and shows great promise for application in the detection of glucose.

  17. Reduction of hydrogen peroxide-induced erythrocyte damage by Carica papaya leaf extract.

    PubMed

    Okoko, Tebekeme; Ere, Diepreye

    2012-06-01

    To investigate the in vitro antioxidant potential of Carica papaya (C. papaya) leaf extract and its effect on hydrogen peroxide-induced erythrocyte damage assessed by haemolysis and lipid peroxidation. Hydroxyl radical scavenging activities, hydrogen ion scavenging activity, metal chelating activity, and the ferrous ion reducing ability were assessed as antioxidant indices. In the other experiment, human erythrocytes were treated with hydrogen peroxide to induce erythrocyte damage. The extract (at various concentrations) was subsequently incubated with the erythrocytes and later analysed for haemolysis and lipid peroxidation as indices for erythrocyte damage. Preliminary investigation of the extract showed that the leaf possessed significant antioxidant and free radical scavenging abilities using in vitro models in a concentration dependent manner (P<0.05). The extract also reduced hydrogen peroxide induced erythrocyte haemolysis and lipid peroxidation significantly when compared with ascorbic acid (P<0.05). The IC50 values were 7.33 mg/mL and 1.58 mg/mL for inhibition of haemolysis and lipid peroxidation, respectively. In all cases, ascorbic acid (the reference antioxidant) possessed higher activity than the extract. The findings show that C. papaya leaves possess significant bioactive potential which is attributed to the phytochemicals which act in synergy. Thus, the leaves can be exploited for pharmaceutical and nutritional purposes.

  18. Reduction of hydrogen peroxide-induced erythrocyte damage by Carica papaya leaf extract

    PubMed Central

    Okoko, Tebekeme; Ere, Diepreye

    2012-01-01

    Objective To investigate the in vitro antioxidant potential of Carica papaya (C. papaya) leaf extract and its effect on hydrogen peroxide-induced erythrocyte damage assessed by haemolysis and lipid peroxidation. Methods Hydroxyl radical scavenging activities, hydrogen ion scavenging activity, metal chelating activity, and the ferrous ion reducing ability were assessed as antioxidant indices. In the other experiment, human erythrocytes were treated with hydrogen peroxide to induce erythrocyte damage. The extract (at various concentrations) was subsequently incubated with the erythrocytes and later analysed for haemolysis and lipid peroxidation as indices for erythrocyte damage. Results Preliminary investigation of the extract showed that the leaf possessed significant antioxidant and free radical scavenging abilities using in vitro models in a concentration dependent manner (P<0.05). The extract also reduced hydrogen peroxide induced erythrocyte haemolysis and lipid peroxidation significantly when compared with ascorbic acid (P<0.05). The IC50 values were 7.33 mg/mL and 1.58 mg/mL for inhibition of haemolysis and lipid peroxidation, respectively. In all cases, ascorbic acid (the reference antioxidant) possessed higher activity than the extract. Conclusions The findings show that C. papaya leaves possess significant bioactive potential which is attributed to the phytochemicals which act in synergy. Thus, the leaves can be exploited for pharmaceutical and nutritional purposes. PMID:23569948

  19. The effect of melanin on iron associated decomposition of hydrogen peroxide.

    PubMed

    Pilas, B; Sarna, T; Kalyanaraman, B; Swartz, H M

    1988-01-01

    The effects of melanin on the iron-catalyzed decomposition of hydrogen peroxide to hydroxyl radicals and hydroxyl ions have been studied using electron spin resonance, spin trapping and visible light spectrophotometry. Melanin altered these reactions by several different mechanisms and consequently, depending on conditions, can significantly increase or decrease the yield of reactive products, including hydroxyl radicals. For low concentrations of ferrous ions, melanin decreased the yield of hydroxyl radicals due to binding of ferrous ions by melanin; ferrous ions bound to melanin did not decompose H2O2 efficiently. Melanins increased the rate of hydroxyl radical production if the predominant form of iron was ferric, due to the ability of melanin to reduce ferric to ferrous iron. Hydroxyl radical production in the presence of a strong chelator (e.g. EDTA) and melanin was greater than in the presence of a weak chelator (e.g. ADP) and melanin. Melanin also increased the rate of destruction of the DMPO-OH adduct.

  20. Prussian blue nanoparticles as peroxidase mimetics for sensitive colorimetric detection of hydrogen peroxide and glucose.

    PubMed

    Zhang, Weimin; Ma, Diao; Du, Jianxiu

    2014-03-01

    Prussian blue nanoparticles (PB NPs) exhibits an intrinsic peroxidase-like catalytic activity towards the hydrogen peroxide (H2O2)-mediated oxidation of classical peroxidase substrate 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt to produce a colored product. The catalysis follows Michaelis-Menen kinetics and shows strong affinity for H2O2. Using PB NPs as a peroxidase mimetics, a colorimetric method was developed for the detection of 0.05-50.0 μM H2O2, with a detection limit of 0.031 μM. When the catalytic reaction of PB NPs was coupled with the reaction of glucose oxidation catalyzed by glucose oxidase, a sensitive and selective colorimetric method for the detection of glucose was realized. The limit of detection for glucose was determined to be as low as 0.03 μM and the linear range was from 0.1 μM to 50.0 μM. The method was successfully applied to the determination of glucose in human serum. Compared with other nanomaterials-based peroxidase mimetics, PB NPs provides 10-100 times higher sensitivity toward the detection of H2O2 and glucose. The detection platform developed showed great potential applications in varieties of physiological importance substances when merged with appropriate H2O2-producing oxidases. Copyright © 2013 Elsevier B.V. All rights reserved.