Guidelines for potentiometric measurements in suspensions Part A. The suspension effect (IUPAC Technical Report)

An explanation of the origin and interpretation of the suspension effect (SE) is presented in accordance with "pH Measurement: IUPAC Recommendations 2002" [Pure Appl. Chem.74, 2169 (2002)]. It is based on an analysis of detailed schemes of suspension potentiometric cells and confirmed with experimental results. Historically, the term "suspension effect" evolved during attempts to determine electrochemically the thermodynamically defined activity of H+ (aq) in suspensions. The experimental SE arises also in determining other pIon values, analogous to pH values.The SE relates to the observation that for the potential generated when a pair of electrodes (e.g., reference electrode, RE, and glass electrode) is placed in a suspension, the measured cell voltage is different from that measured when they are both placed in the separate equilibrium solution (eqs). The SE is defined here as the sum of: (1) the difference between the mixed potential of the indicator electrode (IE) in a suspension and the IE potential placed in the separated eqs; and (2) the anomalous liquid junction potential of the RE placed in the suspension. It is not the consequence of a boundary potential between the sediment and its eqs in the suspension potentiometric cells as is stated in the current definition of the SE.

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Guidelines for potentiometric measurements in suspensions Part B. Guidelines for practical pH measurements in soil suspensions (IUPAC Recommendations 2006)

Pure and Applied Chemistry ◽

10.1351/pac200779010081 ◽

2007 ◽

Vol 79 (1) ◽

pp. 81-86 ◽

Cited By ~ 8

Author(s):

Srecko F. Oman ◽

M. Filomena Camões ◽

Kipton J. Powell ◽

Raj Rajagopalan ◽

Petra Spitzer

Keyword(s):

Reference Electrode ◽

Operational Definition ◽

Indicator Electrode ◽

Liquid Junction ◽

Cell Potential ◽

Technical Report ◽

Potentiometric Measurements ◽

Suspension Effect ◽

The Difference ◽

Definition Of

The measured cell potentials for suspension potentiometric cells have been interpreted and explained by a detailed analysis of the schemes for these cells ["Guidelines for potentiometric measurements in suspensions. Part A. The suspension effect (IUPAC Technical Report", Pure Appl. Chem.79, 67 (2007)]. Some former disagreements amongst investigations have been clarified. A new unambiguous operational definition of the suspension effect (SE) is presented. It is defined as the difference in cell potential for two suspension potentiometric cells, one with both electrodes in the separated equilibrium solution (eqs) and the other with both electrodes in the sediment or suspension. This potential difference is the sum of the change in the indicator electrode (IE) potential and the change in the liquid junction potential of the reference electrode (RE), when the electrodes are used for measurement, once in the sediment of the suspension and then in its eqs.

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Influence of Erythrocytes on Direct Potentiometric Determination of Sodium and Potassium

Annals of Clinical Biochemistry International Journal of Laboratory Medicine ◽

10.1177/000456328302000211 ◽

1983 ◽

Vol 20 (2) ◽

pp. 116-120 ◽

Cited By ~ 8

Author(s):

P Bijster ◽

H L Vader ◽

C L J Vink

Keyword(s):

Whole Blood ◽

Potassium Concentration ◽

Reference Electrode ◽

Sodium Concentration ◽

General Phenomenon ◽

Liquid Junction ◽

Direct Potentiometry ◽

The Difference ◽

Sodium And Potassium

We have shown that the sodium concentration in whole blood measured by direct potentiometry is higher than in plasma. The ‘erythrocyte-effect’, already described by Siggaard Andersen, is most pronounced for instruments equipped with a reference electrode with an open static liquid junction and is thus a general phenomenon. Instruments with a modified liquid junction show less interference. The same phenomenon appears for the determination of the potassium concentration, although the difference between whole blood and plasma, when measured with instruments equipped with a modified liquid junction, can be neglected in practice.

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The errors involved in pH determination in soils.

Australian Journal of Agricultural Research ◽

10.1071/ar9540716 ◽

1954 ◽

Vol 5 (4) ◽

pp. 716 ◽

Cited By ~ 13

Author(s):

M Raupach

Keyword(s):

Reference Electrode ◽

Glass Electrode ◽

Measuring System ◽

Ph Measurements ◽

Soil Systems ◽

Water Suspensions ◽

Supernatant Liquid ◽

Soil Variation ◽

Single Determination ◽

Suspension Effect

Errors of replication of pH values of 1: 5 soil-water suspensions are shown to differ significantly between routine observers and to be larger when duplicate determinations are made upon different days rather than on the same day. For the routine technique employed in these laboratories the 5 per cent. fiducial limits of a single determination do not rise above ±0.09 pH units due to the above causes. Errors due to soil variation over small distances in the field may show 5 per cent. limits as high as ±1.3 pH units. The causes of the errors which may arise within the measuring system are considered and details are given of errors in soil systems due to the suspension effect and to lack of equilibrium between the soil and aqueous phases. Absence of equilibrium may give differences as high as 1.0 unit when measurements are made upon sedimenting alkaline suspensions; no errors occur due to this cause below pH 5. The presence of salts does not modify the differences observed. The suspension effect is relatively small. It is recommended that where possible, pH measurements be made upon soil systems with the glass electrode in the suspension and the reference electrode in the dialysate or supernatant liquid. The description and use of a suitable electrode arrangement is given in an appendix. Generally pH measurements can be considered to no greater accuracy than ±0.1 unit and quite often circumstances do not justify this precision.

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Direct potentiometric determination of sodium ion in blood. I. Potentiometric response in simple sodium chloride solutions.

Clinical Chemistry ◽

10.1093/clinchem/30.1.6 ◽

1984 ◽

Vol 30 (1) ◽

pp. 6-10 ◽

Cited By ~ 6

Author(s):

P Bijster ◽

K L Vink

Keyword(s):

Reference Electrode ◽

Calibration Graph ◽

Sodium Ion ◽

Liquid Junction Potential ◽

Liquid Junction ◽

Sodium Chloride Solutions ◽

Potentiometric Response ◽

Nacl Concentration ◽

Ion Activity ◽

Junction Potential

Abstract We measured the emf of NaCl solutions (120-160 mmol/L) with a home-built cell in steady-state and with some commercial direct potentiometric analyzers about 20 s after the sample is introduced into the instrument. We compared the results with the theoretical sodium ion activity calculated according to different thermodynamic theories. The slope of the calibration graph was calculated with and without correction for the influence of NaCl concentration on the liquid junction potential of the calomel reference electrode. We conclude that different theories used to calculate the sodium ion activity in the concentration range investigated give almost the same results; furthermore, introduction of the liquid junction potential leads to a more nernstian-like slope of the calibration graph. Measurement of identical NaCl solutions with various commercial analyzers showed different displayed concentrations, presumably because of differences in junction structure, measuring time, and concentration of calibration solutions.

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Protein Interferes with Ionised Calcium Measurement at the Reference Electrode Liquid Junction

Annals of Clinical Biochemistry International Journal of Laboratory Medicine ◽

10.1177/000456328702400409 ◽

1987 ◽

Vol 24 (4) ◽

pp. 400-407 ◽

Cited By ~ 11

Author(s):

R B Payne ◽

D P Jones

Keyword(s):

Protein Concentration ◽

Calcium Concentration ◽

Reference Electrode ◽

Liquid Junction ◽

Human Control ◽

Control Serum ◽

Ionised Calcium ◽

Clinically Significant ◽

Calcium Measurement ◽

Junction Potential

The ionised calcium concentration of sequential retentates prepared by ultrafiltration of a human control serum increased with increasing protein concentration when measured with both a Nova 2 and a Radiometer ICA1 analyser using their standard reference electrodes. In contrast, the ionised calcium in the same retentates fell slightly with increasing protein when the reference electrode liquid junctions of the instruments were changed from hypertonic to isotonic solutions, the values then paralleling those in the filtrates. Thus, the clinically significant positive relationship between ionised calcium and protein that has been reported with the Nova 2 and ICA1 analysers is almost certainly an effect of protein on the reference electrode liquid junction potential rather than a consequence of a Donnan effect on true ionised calcium distribution.

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An Isotonic Potassium Chloride Liquid Junction Minimises the Effects of Ionic Strength, Protein and Haematocrit on Ionised Calcium Measurement

Annals of Clinical Biochemistry International Journal of Laboratory Medicine ◽

10.1177/000456328802500305 ◽

1988 ◽

Vol 25 (3) ◽

pp. 228-232 ◽

Cited By ~ 6

Author(s):

R B Payne

Keyword(s):

Ionic Strength ◽

Potassium Chloride ◽

Calcium Concentration ◽

Reference Electrode ◽

Sodium Formate ◽

Liquid Junction ◽

Ionised Calcium ◽

Isotonic Sodium Chloride ◽

Calcium Measurement ◽

Junction Potential

When the reference electrode liquid junction of a Nova 2 analyser was changed to isotonic potassium chloride, increasing the ionic strength of aqueous solutions containing a constant total calcium concentration had a negligible effect on measured ionised calcium. In contrast, measurements using hypertonic potassium chloride, hypertonic sodium formate and isotonic sodium chloride liquid junctions showed significant sample ionic strength effects. Interferences by sample protein concentration and haematocrit were marked with hypertonic, but negligible with isotonic junctions. Ionised calcium values in samples containing 25 mmol/L acetate, bicarbonate, β-hydroxybutyrate, lactate or pyruvate were all lower by 6–7% with an isotonic than a hypertonic potassium chloride junction. Thus, anions that replace bicarbonate during metabolic acidosis have a similar effect on residual liquid junction potential. The clinical usefulness of an isotonic potassium chloride liquid junction needs to be evaluated.

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Estimation of the thermal liquid junction potential of an external pressure balanced reference electrode

Journal of Electroanalytical Chemistry ◽

10.1016/0022-0728(95)04318-7 ◽

1996 ◽

Vol 403 (1-2) ◽

pp. 25-30 ◽

Cited By ~ 25

Author(s):

S.N. Lvov ◽

D.D. Macdonald

Keyword(s):

Reference Electrode ◽

External Pressure ◽

Liquid Junction Potential ◽

Liquid Junction ◽

Junction Potential

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The Distinction between [P] and [S]

10.23943/princeton/9780691161006.003.0018 ◽

2017 ◽

Author(s):

Galen Strawson

Keyword(s):

Personal Identity ◽

Radical Change ◽

Legal Responsibility ◽

The Difference ◽

Definition Of ◽

Over Time

This chapter examines the difference between John Locke's definition of a person [P], considered as a kind of thing, and his definition of a subject of experience of a certain sophisticated sort [S]. It first discusses the equation [P] = [S], where [S] is assumed to be a continuing thing that is able to survive radical change of substantial realization, as well as Locke's position about consciousness in relation to [P]'s identity or existence over time as [S]. It argues that Locke is not guilty of circularity because he is not proposing consciousness as the determinant of [S]'s identity over time, but only of [S]'s moral and legal responsibility over time. Finally, it suggests that the terms “Person” and “Personal identity” pull apart, in Locke's scheme of things, but in a perfectly coherent way.

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L'anglicisme dans la langue française

Digital Press Social Sciences and Humanities ◽

10.29037/digitalpress.43286 ◽

2019 ◽

Vol 3 ◽

pp. 00013

Author(s):

Danny Susanto

Keyword(s):

English Language ◽

Oil Industry ◽

English Word ◽

Public Institutions ◽

Font Size ◽

The World ◽

French Speaking ◽

The Difference ◽

Definition Of ◽

Bibliographic Study

The purpose of this study is to analyze the phenomenon known as “anglicism”: a loan made to the English language by another language. Anglicism arose either from the adoption of an English word as a result of a translation defect despite the existence of an equivalent term in the language of the speaker, or from a wrong translation, as a word-by-word translation. Said phenomenon is very common nowadays and most languages of the world including making use of some linguistic concepts such as anglicism, neologism, syntax, morphology etc, this article addresses various aspects related to Anglicisms in French through a bibliographic study: the definition of Anglicism, the origin of Anglicisms in French and the current situation, the areas most affected by Anglicism, the different categories of Anglicism, the difference between French Anglicism in France and French-speaking Canada, the attitude of French-speaking society towards to the Anglicisms and their efforts to stop this phenomenon. The study shows that the areas affected are, among others, trade, travel, parliamentary and judicial institutions, sports, rail, industrial production and most recently film, industrial production, sport, oil industry, information technology, science and technology. Various initiatives have been implemented either by public institutions or by individuals who share concerns about the increasingly felt threat of the omnipresence of Anglicism in everyday life.

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Electrodiffusion Phenomena in Neuroscience and the Nernst–Planck–Poisson Equations

Electrochem ◽

10.3390/electrochem2020014 ◽

2021 ◽

Vol 2 (2) ◽

pp. 197-215

Author(s):

Jerzy J. Jasielec

Keyword(s):

Electrical Potential ◽

Signal Propagation ◽

Liquid Junction Potential ◽

Liquid Junction ◽

Patch Clamp Technique ◽

Poisson Equations ◽

Cellular Environment ◽

Electrochemical Transport ◽

Insight Into ◽

Junction Potential

This work is aimed to give an electrochemical insight into the ionic transport phenomena in the cellular environment of organized brain tissue. The Nernst–Planck–Poisson (NPP) model is presented, and its applications in the description of electrodiffusion phenomena relevant in nanoscale neurophysiology are reviewed. These phenomena include: the signal propagation in neurons, the liquid junction potential in extracellular space, electrochemical transport in ion channels, the electrical potential distortions invisible to patch-clamp technique, and calcium transport through mitochondrial membrane. The limitations, as well as the extensions of the NPP model that allow us to overcome these limitations, are also discussed.

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