Assignment of reference pH-values to primary standard buffer solutions for standardization of potentiometric sensors in acetonitrile-water mixtures

1995 ◽  
Vol 353 (2) ◽  
pp. 148-155
Author(s):  
Jos� Barbosa ◽  
Victoria Sanz-Nebot
Keyword(s):  
Primary Standard ◽  
Potentiometric Sensors ◽  
Buffer Solutions ◽  
Ph Values ◽  
Standard Buffer

scholarly journals Provisional pH values for certain standard buffer solutions

1942 ◽  
Vol 29 (3) ◽  
pp. 183 ◽  
Author(s):  
Roger G. Bates ◽  
Walter J. Hamer ◽  
George G. Manov ◽  
S.F. Acree
Keyword(s):  
Buffer Solutions ◽  
Ph Values ◽  
Standard Buffer

A simple method for the determination of the pH values of turbid soil and other solutions

1928 ◽  
Vol 18 (2) ◽  
pp. 206-208 ◽  
Author(s):  
C. H. Gadd
Keyword(s):  
Pathological Condition ◽  
Ratio Method ◽  
Exact Matching ◽  
Simple Method ◽  
Considerable Difficulty ◽  
Buffer Solutions ◽  
Ph Values ◽  
Standard Buffer ◽  
Soil Solutions

In the course of investigations into the cause of an obscure pathological condition of the tea bush, it became necessary to make pH determinations of certain soils. Electrometric apparatus and a suitable centrifuge for clearing the solutions were not available. Considerable difficulty was experienced in making the determinations with accuracy by indicator methods owing to two causes. First, the turbidity of the soil solutions made comparison with standard buffer solutions somewhat difficult; secondly, the colours developed in the soil and buffer solutions with some indicators were different in hue, as distinct from shade or tint. This rendered exact matching quite impossible. The latter difficulties also arose when the drop ratio method was used instead of standard buffer solutions. The errors resulting from these causes were believed to be unduly large, and it was felt that greater accuracy would be attained if these difficulties could be overcome.

The Interfacial Behaviour of Mono-, Di-, and Triphosphate of Inosine at the Charged Interface

1996 ◽  
Vol 61 (11) ◽  
pp. 1600-1608
Author(s):  
Mohamed E. Ahmed
Keyword(s):  
Divalent Metal ◽  
Divalent Metal Ions ◽  
Adsorption Parameters ◽  
Buffer Solutions ◽  
Ph Values ◽  
Adsorption Equilibria ◽  
Charged Interface ◽  
Interfacial Behaviour ◽  
Phase Sensitive ◽  
Adsorption Stage

The interfacial behaviour and adsorption equilibria of mono-, di-, and triphosphate of inosine (IMP, IDP, and ITP) were carried out in different buffer solutions by phase-sensitive ac voltammetry at HMDE. The characteristic properties and adsorption parameters of dilute and compact layers were evaluated from the obtained Frumkin isotherm at different pH values. The effect of some divalent metal ions on the adsorption stage and association of the investigated compounds has been studied.

scholarly journals The pH measurement with glass electrode in an electromagnetic field

2016 ◽  
Vol 81 (12) ◽  
pp. 1407-1414 ◽  
Author(s):  
Dragan Veselinovic ◽  
Zoran Velikic
Keyword(s):  
Electromagnetic Field ◽  
Buffer Capacity ◽  
Extreme Values ◽  
Ph Value ◽  
Radiation Power ◽  
Glass Electrode ◽  
Frequency Interval ◽  
Buffer Solutions ◽  
Ph Values ◽  
Glass Electrodes

Measurements of pH values of buffer solutions (pH 4.0, 7.0 and 10.0) and distilled water have been performed with a glass electrode in electromagnetic field at the frequency interval of 10 MHz to 200 MHz and the output power of dispersed and reflected electromagnetic radiation of 0.01 W to 3 W. In all the cases, there occurred a reduction of pH values, i.e. a "recorded pH value" was obtained. The reduction appears within the applied frequency interval reaching extreme values at specific frequencies. The reduction of the pH values increases with the radiation power and depend of the solution buffer capacity. The effect of electromagnetic field on pH value change is exerted dominantly through the influence on glass electrodes.

Evaluation of a system for intragastric pH monitoring of intensive care unit patients: preliminary report

1992 ◽  
Vol 1 (1) ◽  
pp. 81-84 ◽  
Author(s):  
JM Clochesy
Keyword(s):  
Ph Monitoring ◽  
Gastric Ph ◽  
Gastric Aspirate ◽  
Ph Probe ◽  
Buffer Solutions ◽  
Ph Values ◽  
Small Series ◽  
Significant Difference

BACKGROUND: A new pH probe-tipped nasogastric sump tube is available to monitor gastric pH conveniently. This study assesses its ability to measure gastric acidity accurately. METHODS: The accuracy of the combined pH probe nasogastric tube (GrapHprobe ST) was determined by comparing it with standard buffer solutions (pH 1.0, 2.0, 4.0 and 7.0) traceable to the National Institute of Standards and Technology. Gastric pH values obtained were compared with values obtained using indicator paper and a calibrated glass electrode on gastric aspirate. RESULTS: Although statistically significant differences were found in vitro between the pH of three of the buffer solutions and the pH values obtained by the nasogastric sump tube, the results were within 0.5 pH unit. When rounded to the nearest pH unit, all values were the same as the buffer solutions. No significant difference was found in the pH values obtained during in vivo testing. CONCLUSIONS: The GrapHprobe ST measured gastric pH within reasonable accuracy in this small series.

Morphological and Electrical Properties of Silicon Dioxide-Based Interdigitated Electrode Arrays

2015 ◽  
Vol 1109 ◽  
pp. 253-256 ◽  
Author(s):  
M.A. Farehanim ◽  
U. Hashim ◽  
Norhayati Soin ◽  
A.H. Azman ◽  
S. Norhafiezah ◽  
...  
Keyword(s):  
Electrical Properties ◽  
Silicon Dioxide ◽  
Ph Value ◽  
Ph Measurement ◽  
Electrode Arrays ◽  
Interdigitated Electrode ◽  
Buffer Solutions ◽  
Ph Values ◽  
Ph Buffer ◽  
Higher Sensitivity

The electrical performances of silicon dioxide-based Interdigitated electrodes (IDEs) as biosensor were developed. The IDEs was made up by two individually addressable Interdigitated comb-like finger structure have frequently been suggested as a biosensor which promises higher sensitivity compared to conventional parallel electrodes. The purpose of this paper was to investigate the capacitance test and impedance test to taken with various pH solution to observe the response of the sensor with different pH values. Purchased pH buffer solutions which varied from pH2 to pH10 are dropped on the microelectrode and the effect on it is investigated for the application in pH measurement. This research has proven that increase in pH value from acidic to alkaline is proportional with capacitance. The measured values of capacitance with respect to each pH concentrations applied during the measurements were repeatable and reproducible.

scholarly journals Curcumin Incorporation into Zn3Al Layered Double Hydroxides—Preparation, Characterization and Curcumin Release

Crystals ◽  
2020 ◽  
Vol 10 (4) ◽  
pp. 244 ◽  
Author(s):  
Octavian D. Pavel ◽  
Ariana Şerban ◽  
Rodica Zăvoianu ◽  
Elena Bacalum ◽  
Ruxandra Bîrjega
Keyword(s):  
Layered Double Hydroxides ◽  
Curcuma Longa ◽  
Nano Particles ◽  
Molar Ratio ◽  
Attenuated Total Reflectance ◽  
Buffer Solutions ◽  
Ph Values ◽  
Main Crystalline Phase ◽  
Ph Increase ◽  
Double Hydroxides

Curcumin (CR) is a natural antioxidant compound extracted from Curcuma longa (turmeric). Until now, researches related to the incorporation of CR into layered double hydroxides (LDHs) were focused only on hybrid structures based on a MgxAl-LDH matrix. Our studies were extended towards the incorporation of CR in another type of LDH-matrix (Zn3Al-LDH) which could have an even more prolific effect on the antioxidant activity due to the presence of Zn. Four CR-modified Zn3Al-LDH solids were synthesized, e.g., PZn3Al-CR(Aq), PZn3Al-CR(Et), RZn3Al-CR(Aq) and RZn3Al-CR(Et) (molar ratio CR/Al = 1/10, where P and R stand for the preparation method (P = precipitation, R = reconstruction), while (Aq) and (Et) indicate the type of CR solution, aqueous or ethanolic, respectively). The samples were characterized by XRD, Attenuated Total Reflectance Fourier Transformed IR (ATR-FTIR) and diffuse reflectance (DR)-UV–Vis techniques and the CR-release was investigated in buffer solutions at different pH values (1, 2, 5, 7 and 8). XRD results indicated a layered structure for PZn3Al-CR(Aq), PZn3Al-CR(Et), RZn3Al-CR(Aq) impurified with ZnO, while RZn3Al-CR(Et) contained ZnO nano-particles as the main crystalline phase. For all samples, CR-release revealed a decreasing tendency towards the pH increase, and higher values were obtained for RZn3Al-CR(Et) and PZn3Al-CR(Et) (e.g., 45% and 25%, respectively at pH 1).

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