Determination of reserve alkalinity of engine coolants and antirusts according to ASTM D1121

Corrosion of metallic components is an inherent problem for engines, because metals naturally tend to oxidize in the presence of water and/or low pH value. The reserve alkalinity of engine coolants and antirusts is a measure of the buffering ability to absorb acid. A fast and accurate determination is therefore important. Engine coolants or antirusts are dissolved in water. After a pH measurement, a determination by potentiometric titration using the Profitrode and hydrochloric acid as titrant is carried out.