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SMIIC MC Training on the primary measurement of pH by Harned Cell

The fourth SMIIC MC Training within the SMIIC MC Work Plan 2021 – 2023  was the The primary measurement of pH by Harned Cell took place on the 10 August 2021 virtually, technically hosted by SMIIC General Secretariat.

The training is hosted by NMI: SASO National Metrology and Calibration Center.

General Description: The training covered the theory and primary measurements of pH

Objective: To provide knowledge to participants working on the preparation and certification of primary buffer solutions

Who should attend: The training was intended for staff working at electrochemical laboratories at National Metrology Institutes on the preparation of primary buffers.

References used: for International Union of Pure and Applied Chemistry Measurement of pH. Definition, Standards, and Procedures (IUPAC Recommendations 2002)

Guide to the expression of uncertainty in measurement (GUM)

Lecturers: Mr. Abdulrahman R. Alaskar (ar.askar@saso.gov.sa)

Proof Dr. Adel B. Shehata (a.shehata@saso.gov.sa)


 Brief Historical of the pH traceability

 The primary method of pH measurements

 - Theory

 - Determination of HCl conc. by Coulometry

 - Traceabılıty of Coulometric measurements

 - The standard potential of Ag/AgCl electrode

 - Measurement of the acidity function, pa

 - Extrapolation of the acidity function (pa0 )

 - The activity coefficient of the chloride ion, ƴCl

 - Traceability of the primary pH results

 - Uncertainty of the primary pH results

 - Gravimetric preparation of the primary buffers