The Infona portal uses cookies, i.e. strings of text saved by a browser on the user's device. The portal can access those files and use them to remember the user's data, such as their chosen settings (screen view, interface language, etc.), or their login data. By using the Infona portal the user accepts automatic saving and using this information for portal operation purposes. More information on the subject can be found in the Privacy Policy and Terms of Service. By closing this window the user confirms that they have read the information on cookie usage, and they accept the privacy policy and the way cookies are used by the portal. You can change the cookie settings in your browser.
Regenerated silk fibroin prepared from waste silk was employed as immobilization matrix for peroxidase and the structures of the blend membranes of regenerated silk fibroin and peroxidase were first investigated with IR and scanning electron microscopy. There was intermolecular interaction between peroxidase and regenerated silk fibroin in the immiscible state. Cyclic voltammetry and constant applied...
A rapid and highly sensitive potentiometric flow-injection method for the determination of trace hydrogen peroxide was developed by use of an Fe(III)-Fe(II) potential buffer solution containing bromide and Mo(VI). The analytical method was based on a linear relationship between a concentration of hydrogen peroxide and a largely transient potential change of an oxidation-reduction potential electrode...
The thin-layer chromatographic (TLC) behaviour of 64 ions including Zr(IV) and Hf(IV) has been surveyed on systems composed of silica gel and of nitric acid and nitric acid-hydrogen peroxide media. In the 0.5 mol l -1 HNO 3 -3% (w/v) H 2 O 2 solution, only Hf(IV) adsorbed very strongly, whereas Zr(IV) and many other ions showed no or weak adsorption. Stepwise...
The reaction between hexacyanomanganate(IV) and hydrogen peroxide in acidic medium is strongly catalysed by vanadium. The stoichiometry has been proved to be Δ[Mn(IV)]/Δ[H 2 O 2 ]=1. S-shaped absorbance-time curves are obtained for a wide range of conditions, which seems to be due to the transient formation of hydroperoxyl radicals, HO 2 .; therefore, the reaction is autoinduced...
Silica gel and glass beads were modified by using acid chloride of metal–tetrakis(4-carboxyphenyl)porphine (M–TCPP) through a peptide bond, and an anion-exchange resin with M–TCPP by ion-exchange reaction and physical adsorption. The carriers modified with Co3+–TCPP proved to accelerate the redox reaction which is catalyzed by glutathione oxidase (GSHOx), while those modified with Mn3+–TCPP exhibited...
Fluorophotometric determinations of cobalt(II) and hydrogen peroxide were investigated by using the fluorescence reaction between fluorescein-hydrazide (fl-NHNH 2 ), and/or hydrogen peroxide, cobalt(II), respectively. The calibration graphs were liner in the range of 0-6.0 ng cobalt(II) and 0-1000 ng hydrogen peroxide per 10 ml at an emission wavelength (E m ) of 530 nm with an exicitation...
The influence of dissolved organic matter (DOM), such as humic acid (HA) and hydroxybenzoic acids, on the determination of H 2 O 2 via a colorimetric method using N,N-diethyl-p-phenylenediamine (DPD) was examined. The influence of DOM on absorbance decay at 551 nm, which represents the wavelength for maximum absorption of the oxidized species of DPD (DPD + ), were investigated...
A novel chemiluminescence (CL) system was evaluated for the determination of hydrogen peroxide, glucose and ascorbic acid based on hydrogen peroxide, which has a catalytic-cooxidative effect on the oxidation of luminol by KIO 4 . Hydrogen peroxide can be directly determined by luminol-KIO 4 -H 2 O 2 CL system. The detection limit was 3.0x10 -8 mol l ...
A biosensor for the specific determination of hydrogen peroxide was developed using catalase (EC 1.11.1.6) in combination with a dissolved oxygen probe. Catalase was immobilized with gelatin by means of glutaraldehyde and fixed on a pretreated teflon membrane served as enzyme electrode. The electrode response was maximum when 50 mM phosphate buffer was used at pH 7.0 and at 35 o C. The biosensor...
A novel hydrogen peroxide (H 2 O 2 ) potentiometric sensor, made with a MnO 2 -doped carbon paste electrode (CPE), is reported. Under optimum conditions, the electrode gives a Nernstian response for H 2 O 2 in the concentration range 3.00x10 -7 -3.63x10 -4 mol/l, with a slope of 21-19.4 mV/pH 2 O 2 and a detection limit...
A rapid and sensitive method was proposed for the determination of hydrogen peroxide based on the catalytic effect of hemoglobin using o-phenylenediamine as the substrate. Stopped-flow spectrophotometric method was used to study the kinetic behavior of the oxidation reaction. The catalytic effectiveness of hemoglobin was compared with other four kinds of catalysts. The initial rate of the formation...
The oxidation reaction kinetics of thiocyanate by excess hydrogen peroxide has been studied by using capillary electrophoresis. The paper illustrates for the first time the use of capillary electrophoresis in studying reaction kinetics and provides a non-laborious way to determine the rate law and the rate constant for the above reaction in the pH range 6-8. Standard solutions of thiocyanate were...
A flow injection-photometric method has been developed for the determination of iron(II+III). The method is based on the catalytic effect of iron(III) on the hydrogen peroxide oxidation of 3,3',5,5'-tetramethylbenzidine to form a blue compound (λ max =650 nm). In this catalyzed reaction, 1,10-phenanthroline acted as an effective activator. Iron(II) is also determined, being oxidized...
The flow injection analysis of hydrogen peroxide is proposed, using a redox electrode and an Fe(II)-Fe(III) potential buffer solution. Influencing factors, such as the concentrations of Fe(II)-Fe(III) and sulfuric acid in the potential buffer on sensitivity of the proposed method are examined. The analysis of high concentrations of hydrogen peroxide up to ~10 M was conducted successfully with relative...
A method was developed for estimation of concentrations of cystine based on the reaction of this oxidised amino acid with ascorbic acid and copper ion. The standard curve which was constructed was used as the basis for investigation of the effects which both cystine and glutathione disulphide, and some disulphide proteins, exerted on the amount of hydrogen peroxide formed in the reaction of ascorbic...
Ferric and copper hexacyanoferrates (PB and CuHCF, respectively) were electrodeposited on glassy carbon electrodes providing a suitable catalytic surface for the amperometric detection of hydrogen peroxide. Additionally glucose oxidase was immobilized on top of these electrodes to form glucose biosensors. The biosensors were made by casting glucose oxidase-Nafion layers onto the surface of the modified...
A novel chemiluminescence (CL) system, cobalt(II)-hydrogen peroxide-hydrogencarbonate without luminescent reagents, was described. When cobalt(II) was injected into mixed solution of 0.4 mol l -1 hydrogencarbonate and 0.01 mol l -1 hydrogen peroxide in a flow injection system, CL occurred, which was significantly enhanced when rhodamine B coexisted. The CL emission intensity...
7-(4,6-Dichloro-1,3,5-triazinylamino)-4-methylcoumarin (DTMC) was synthesized as a completely new chemiluminescent reagent, and with it a novel chemiluminescence method was developed for the determination of hydrogen peroxide in the absence of any added catalyst or cooxidant. The chemiluminescence intensity of the DTMC-H 2 O 2 system could be enhanced by the addition of cation surfactants...
Glucose biosensors based on lyophilised, crystalline and cross-linked glucose oxidase (GOx, CLEC(R)) and commercially available lyophilised GOx immobilised on top of glassy carbon electrodes modified with electrodeposited Prussian Blue are critically compared. Two procedures were carried out for preparing the biosensors: (1) deposition of one layer of adsorbed GOx dissolved in an aqueous solution...
A sensor for H 2 O 2 amperometric detection based on a Prussian Blue (PB) bulk modified carbon screen-printed electrode was developed. It has been optimised with respect to the lowest limit of detection achieved. PB was made chemically by the reaction of FeCl 3 with K 4 [Fe(CN) 6 ]. The resulting powder, obtained by forced crystallisation induced by acetone,...
Set the date range to filter the displayed results. You can set a starting date, ending date or both. You can enter the dates manually or choose them from the calendar.