Scope:

ASTM E70 approach is commonly used to characterize aqueous solutions because it provides an accurate measurement of the hydrogen ion concentration. In the chemical industry, pH measurement is one of the most critical process control variables, and it plays a vital role in pollution management.

Procedure

In ASTM E70, the electrodes are cleaned and dried in the sample cup after calibrating the pH meter with two standard solutions. The test solution is poured into a cup section, and a preliminary pH value is obtained. One to three parts of well-buffered test solutions are adequate to provide pH readings that are repeatable to 60.02 units and exhibit drifts of less than 60.01 units in 1 or 2 minutes. The pH of water samples and slightly buffered solutions are measured.

Video 01: ASTM E70 pH measurement of paints

Specimen size:

In ASTM E70, the potential difference between the hydrogen electrode and a glass electrode of the high-alkalinity type shall be the same, within + 3 mV, at pH 12.8 as at pH 9.18.

Results

The pH of the test solution is reported to the nearest 0.01 unit, and the temperature of the test solution is reported to the nearest 1°C.

Conclusion:

ASTM E70 approach is commonly used to characterize aqueous solutions because it provides an accurate measurement of the hydrogen ion concentration.