A biospecific membrane sensor for the determination of sucrose

1983 ◽  
Vol 48 (3) ◽  
pp. 798-804 ◽  
Author(s):  
Lumír Macholán ◽  
Hana Konečná
Keyword(s):  
Thin Film ◽  
Hydrogen Peroxide ◽  
Steady State ◽  
Reaction Layer ◽  
Enzyme Reaction ◽  
Oxygen Electrode ◽  
Reaction Vessel ◽  
Membrane Sensor ◽  
Electrode Response

The paper describes a rapid method for the biospecific determination of sucrose using an oxygen electrode of the Clark type or a platinum disc anode, the measuring part of which is coated by a thin film of invertase, mutarotase and glucose oxidase co-crosslinked by glutardialdehyde together with serum albumin. After injecting the sample into the reaction vessel the current corresponding to the decrease of the oxygen content or to the formation of hydrogen peroxide in the enzyme reaction layer is registered. The steady state electrode response is proportional to the concentration of sucrose within the range of 0.03 to 1.5 mmol . l-1 and is attained during 1-2 minutes with a reproducibility of 3-4%.

Sol−Gel Thin-Film Immobilized Soybean Peroxidase Biosensor for the Amperometric Determination of Hydrogen Peroxide in Acid Medium

1999 ◽  
Vol 71 (10) ◽  
pp. 1935-1939 ◽  
Author(s):  
Bingquan Wang ◽  
Bin Li ◽  
Zhenxin Wang ◽  
Guobao Xu ◽  
Qun Wang ◽  
...  
Keyword(s):  
Thin Film ◽  
Hydrogen Peroxide ◽  
Acid Medium ◽  
Sol Gel ◽  
Soybean Peroxidase ◽  
Amperometric Determination

scholarly journals Improved Protocol for an Oxygen Electrode Method for Determining Hydrogen Peroxide in Foods

1997 ◽  
Vol 80 (3) ◽  
pp. 681-687 ◽  
Author(s):  
Fumio Miyamoto ◽  
Masanobu Saeki ◽  
Takumi Yoshizawa
Keyword(s):  
Hydrogen Peroxide ◽  
Standard Method ◽  
Present Method ◽  
Accurate Determination ◽  
Oxygen Electrode ◽  
Nitrogen Gas ◽  
Naturally Occurring ◽  
Residual Hydrogen ◽  
Electrode Method

Abstract An oxygen electrode method for determining residual hydrogen peroxide in foods has been further improved. Pretreatment, which includes extraction and neutralization, is done in a hydrogen peroxide extraction apparatus with nitrogen gas bubbling. The hydrogen peroxide concentration of the sample is corrected by subtracting the sample blank value, obtained for the sample through catalase treatment. Bubbling with nitrogen gas effectively minimized the sample blank value, making this method suitable for accurate determination of trace amounts of hydrogen peroxide in foods. Recoveries of hydrogen peroxide added at 1-10 μg/g were 77.8-107.1% by the present method. These recoveries are similar to or higher than those by the Japanese standard method and by another modified oxygen electrode method. Concentrations of naturally occurring hydrogen peroxide in solid foods were <0.87 μg/g by the present method, lower than those by either the standard method or another modified oxygen electrode method.

An enzyme electrode for determination of aromatic diamines and aminophenols based on cross-linked ceruloplasmin

1984 ◽  
Vol 49 (3) ◽  
pp. 752-756 ◽  
Author(s):  
Lumír Macholán ◽  
Milan Jílek
Keyword(s):  
Response Time ◽  
Reaction Layer ◽  
Aromatic Amines ◽  
Enzyme Electrode ◽  
Aromatic Diamines ◽  
Oh Groups ◽  
Electrode Response ◽  
Marked Selectivity ◽  
Better Than

The determination of aromatic amines and phenols by an enzyme pO2 electrode containing cross-linked ceruloplasmin in the reaction layer was examined. The electrode shows at pH 5.5 a marked selectivity for derivatives with-NH2 or NR2, resp., and -OH-groups in para and ortho position while its sensitivity for aromatic diamines is better than its sensitivity for aminophenols and polyphenols. p-Phenylenediamine and its N,N-dialkyl derivatives are the best analytes which can be detected starting from concentrations of 10-5 mol l-1 and higher; the reproducibility is 5-7% at an electrode response time of 2-5 min.

scholarly journals Thin-film SnO<sub>2</sub> and ZnO detectors of hydrogen peroxide vapors

2018 ◽  
Vol 7 (1) ◽  
pp. 281-288 ◽  
Author(s):  
Vladimir Aroutiounian ◽  
Valeri Arakelyan ◽  
Mikayel Aleksanyan ◽  
Gohar Shahnazaryan ◽  
Petr Kacer ◽  
...  
Keyword(s):  
Thin Film ◽  
Hydrogen Peroxide ◽  
Gas Sensing ◽  
Operating Temperature ◽  
Vapor Concentration ◽  
Linear Character ◽  
Vapor Sensors ◽  
Sensing Characteristics ◽  
Hydrogen Peroxide Vapor

Abstract. Thin-film hydrogen peroxide vapor sensors made from Co-doped SnO2 and La-doped ZnO were manufactured using the high-frequency magnetron sputtering method. Thicknesses of deposited doped metal oxide films were measured and their morphology was investigated. The gas sensing characteristics of the prepared sensors were measured at different concentrations of hydrogen peroxide vapors and different operating temperatures of the sensor. It was found that both sensors made from doped metal oxides SnO2 and ZnO exhibit a sufficient response to 10 ppm of hydrogen peroxide vapors at the 200 and 220 ∘C operating temperature, respectively. It was established that the dependencies of the response on hydrogen peroxide vapor concentration have a linear character for prepared structures at the 150 ∘C operating temperature and can be used for determination of hydrogen peroxide vapor concentration.

Studies on Water in the Hydration Chamber of a Modified Electron Microscope

1970 ◽  
Vol 28 ◽  
pp. 544-545
Author(s):  
R. C. Moretz ◽  
G. G. Hausner ◽  
D. F. Parsons
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Electron Microscope ◽  
Steady State ◽  
Room Temperature ◽  
Small Mass ◽  
Equilibrium Pressure ◽  
Biological Objects ◽  
Mechanical Pump ◽  
Differential Pumping

Use of the electron microscope to examine wet objects is possible due to the small mass thickness of the equilibrium pressure of water vapor at room temperature. Previous attempts to examine hydrated biological objects and water itself used a chamber consisting of two small apertures sealed by two thin films. Extensive work in our laboratory showed that such films have an 80% failure rate when wet. Using the principle of differential pumping of the microscope column, we can use open apertures in place of thin film windows.Fig. 1 shows the modified Siemens la specimen chamber with the connections to the water supply and the auxiliary pumping station. A mechanical pump is connected to the vapor supply via a 100μ aperture to maintain steady-state conditions.

The measurement of thin-film reaction layers with high-resolution FESEM

1995 ◽  
Vol 53 ◽  
pp. 330-331
Author(s):  
Paul G. Kotula ◽  
C. Barry Carter
Keyword(s):  
Thin Film ◽  
High Resolution ◽  
Reaction Layer ◽  
Product Layer ◽  
Buffer Layers ◽  
Oxide Superconductors ◽  
Rate Limiting Step ◽  
Ceramic Thin Film ◽  
Backscattered Electron ◽  
Boundary Reaction

Thin-film reactions in ceramic systems are of increasing importance as materials such as oxide superconductors and ferroelectrics are applied in thin-film form. In fact, reactions have been found to occur during the growth of YBa2Cu3O6+x on ZrO2. Additionally, thin-film reactions have also been intentionally initiated for the production of buffer layers for the subsequent growth of high-Tc superconductor thin films. The problem is that the kinetics of ceramic thin-film reactions are not well understood when the reaction layer is very thin; that is, when the rate-limiting step is a phase-boundary reaction as opposed to diffusion of the reactants through the product layer. In this case, the reaction layer is likely to be laterally non-uniform. In the present study, the measurement of thin reaction-product layers is accomplished by first digitally acquiring backscattered-electron images in a high-resolution field-emission scanning electron microscope (FESEM) followed by image analysis. Furthermore, the problem of measuring such small thicknesses (e.g., 20-500nm) over lengths of interfaces longer than 3mm is addressed.

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