GB 6920-1986 (English Version) PDF

Standard No.: GB 6920-1986
Language: Chinese, Available in English version
Release Date: 1986
Published By: General Administration of Quality Supervision, Inspection and Quarantine of the People‘s Republic of China
Latest: GB 6920-1986

Scope: 1.1 This method is applicable to the determination of the pH value of drinking water, surface water and industrial wastewater. 1.2 The color, turbidity, colloidal substances, oxidizing agents, reducing agents and high salt content of water do not interfere with the determination; however, in a strongly acidic solution with pH<1, there will be a so-called "acid error", which can be determined according to acidity; In the alkaline solution with pH > 10, due to the presence of a large amount of sodium ions, an error occurs and the reading is low, which is usually called "sodium difference". To eliminate the "sodium difference", in addition to using a special "low sodium difference" electrode, it is also possible to use a standard buffer solution that is similar to the pH value of the measured solution to calibrate the instrument. Temperature affects the potential of the electrodes and the ionization balance of the water. Attention must be paid to adjusting the compensation device of the instrument to be consistent with the temperature of the solution, and to make the temperature error between the measured sample and the standard buffer solution used for calibrating the instrument within ±1°C.

GB 6920-1986 history

1986 GB 6920-1986 Water quality - Determination of pH value - glass electrode method