How to measure pHT in biological experiments

A simple video tutorial and manual for TRIS buffer preparation, pH probe calibration, sampling and calculations.

Sanja Grđan, University of Dubrovnik & Sam Dupont, University of Gothenburg

Translation by Celeste Sánchez Noguera (Spanish) and Sam Dupont (French)

Measuring pH in seawater using a glass electrode is not trivial and requires TRIS buffer. TRIS buffers are commercially available from Dr. Andrew Dickson's laboratory at the Scripps Institution of Oceanography, California. However, access to this buffer can be difficult due to a continuously increasing demand as well as costs including shipping, customs fees, and taxes, making them less available for countries and laboratory with limited funds.

A simplified buffer preparation method is described in Paulsen & Dickson (2020) making the use of TRIS buffers available to a wider range of researchers.

The aim of this document and associated material (xls sheets and videos) is to help experimentalists entering the field of ocean acidification to make their own TRIS buffer, calibrate their glass electrodes for pH measurement on the total scale, take water samples and calculate pH on the total scale (pH_T).

Click on the following links to download packages including the manual and videos (available in English, French and Spanish).

English 

• Video: How to measure pHT in biological experiments: TRIS buffer preparation
• Video: How to measure pHT in biological experiments: pH probe calibration, sampling and calculations
• Excel: Chemical preparation_TRIS buffer
• Excel: Preparing TRIS buffer
• Excel: TRIS calibration and pHT calculation
• Manual 

French

• Video: Comment mesurer le pHT dans les expérimentations biologiques : Préparation de la solution tampon TRIS
• Video:  Comment mesurer le pHT dans les expérimentations biologiques : calibration de la sonde de pH, échantillonnage et calculs

Spanish

• Video: Cómo medir el pHT en experimentos biológicos: Preparación del tampón TRIS
• Video: Cómo medir el pHT en experimentos biológicos: calibración de la sonda de pH, toma de muestras y cálculos