Definition of pH scales, standard reference values, measurement of pH and related terminology (Recommendations 1984)

Covington, A. K.; Bates, Roger G.; Durst, Richard A.

doi:10.1351/pac198557030531

Cited by 314 publications

(136 citation statements)

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“…A second factor to be noted whilst studying the effect of temperature on the AQ reduction wave is how the pH of the solution will vary with temperature, as the dissociation constants of the components of the buffer solutions vary as the temperature is changed. Therefore, four IUPAC standard buffers (pH 1.5, 4.6, 6.2 and 9.2) were utilised in these studies which have a known pH at a set of temperatures [25]. The corresponding square wave voltammograms obtained in both pH 4.6 (acetate buffer) and pH 9.2 (borax buffer) over a range of temperatures from 20 to 70 8C are detailed in Fig.…”

Section: Voltammetric Response Of Aqcarbon At Elevated Temperature Frmentioning

confidence: 99%

Anthraquinone-derivatised carbon powder: reagentless voltammetric pH electrodes

Wildgoose

2003

Talanta

100

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Section: Voltammetric Response Of Aqcarbon At Elevated Temperature Frmentioning

confidence: 99%

Anthraquinone-derivatised carbon powder: reagentless voltammetric pH electrodes

Wildgoose

2003

Talanta

100

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“…This should avoid the confusion that would be caused by several inconsistent pH scales. This work will necessarily involve a reevaluation of the presently accepted definitions and conventions incorporated in the pH values of the SRMs issued by NBS and of the recommended standards of organizations such as the International Union of Pure and Applied Chemistry [31].…”

Section: Resultsmentioning

confidence: 99%

Standard reference materials :

Wu¹,

Koch²,

Durst³

1988

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In many applications, traceability of quality control and measurement processes to the national measurement system is carried out through the mechanism and use of SRM's.For many of the Nation's scientists and technologists, it is therefore of more than passing interest to know the details of the measurements made at NBS in arriving at the certified values of the SRM's produced.An NBS series of papers, of which this publication is a member, called the NBS Special Publication -260 Series , is reserved for this purposeThe 260 Series is dedicated to the dissemination of information on different phases of the preparation, measurement, certification, and use of NBS SRM's.In general, much more detail will be found in these papers than is generally allowed, or desirable, in scientific journal articles. This enables the user to assess the validity and accuracy of the measurement processes employed, to judge the statistical analysis, and to learn details of techniques and methods utilized for work entailing greatest care and accuracy. These papers also should provide sufficient additional information not found on the certificate so that new applications in diverse fields not foreseen at the time the SRM was originally issued will be sought and found. (SRM's 2023(SRM's , 2024(SRM's , 2025, NBS Spec.Publ. 260-79 (October 1982 In order to ensure the consistency of these measurements, the National Bureau of Standards has recommended an operational scale of pH, maintained in terms of the pH(S) of a series of standard solutions. Certified samples of buffer materials, from which the standard reference solutions of reproducible pH can be prepared, as well as solutions in the case of rainwater, are issued by the National Bureau of Standards as Standard Reference Materials. This report is concerned primarily with a discussion of the method used at NBS for the assignment of pH(S) values to these standard solutions, a description of the NBS measurement facilities for pH, and a summary of the characteristics of the buffer materials. A brief discussion of the types of electrodes used and the calibration of pH instrumentation is also presented. This report is concerned primarily with a description of the concept of pH, its definition, and the method and facilities used at NBS for the assignment of pH values to the standard buffer solutions. A brief discussion is also included of pH instrumentation and some of the potential pit-falls associated with the measurement of pH and the use of these standards. One additional point is worth noting. The pH certificates reproduced in the appendix of this publication refer to specific stocks of the Standard Reference Materials and, since batch-to-batch pH variability exists , the use of these values for other sources of these buffer materials is not recommended.It is anticipated that in the near future the International Union of Pure and Applied Chemistry will recommend a revised pH scale defined by these standards but of sufficiently reduced precision that analytically pure reagents may be used ...

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“…that the difference in electric potential between the electrode solution and buffer solution is the same as that between the electrode solution and sample solution (Covington, 1985). This error is referred to as liquid junction error and has been discussed in several articles describing the potentiometric measurement of pH (Dickson et al, 2007;Illingworth, 1981;Easley and Byrne, 2012).…”

Section: D Macleod Et Al: Technical Note 719mentioning

confidence: 99%

Technical Note: Maximising accuracy and minimising cost of a potentiometrically regulated ocean acidification simulation system

2015

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Abstract. This article describes a potentiometric ocean acidification simulation system which automatically regulates pH through the injection of 100 % CO 2 gas into temperaturecontrolled seawater. The system is ideally suited to longterm experimental studies of the effect of acidification on biological processes involving small-bodied (10-20 mm) calcifying or non-calcifying organisms. Using hobbyist-grade equipment, the system was constructed for approximately USD 1200 per treatment unit (tank, pH regulation apparatus, chiller, pump/filter unit). An overall tolerance of ±0.05 pH T units (SD) was achieved over 90 days in two acidified treatments (7.60 and 7.40) at 12 • C using glass electrodes calibrated with synthetic seawater buffers, thereby preventing liquid junction error. The performance of the system was validated through the independent calculation of pH T (12 • C) using dissolved inorganic carbon and total alkalinity data taken from discrete acidified seawater samples. The system was used to compare the shell growth of the marine gastropod Zeacumantus subcarinatus infected with the trematode parasite Maritrema novaezealandensis with that of uninfected snails at pH levels of 7.4, 7.6, and 8.1.

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Definition of pH scales, standard reference values, measurement of pH and related terminology (Recommendations 1984)

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Cited by 314 publications

References 0 publications

Anthraquinone-derivatised carbon powder: reagentless voltammetric pH electrodes

Anthraquinone-derivatised carbon powder: reagentless voltammetric pH electrodes

Standard reference materials :

Technical Note: Maximising accuracy and minimising cost of a potentiometrically regulated ocean acidification simulation system

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