饮用水的总硬度

Hardness of water is expressed as the level of calcium and magnesium ions converted into mg/L of calcium carbonate (CaCO3). In general, “hardness” is classified into five types as below: a. Total hardness (total amount of calcium and magnesium) b. Calcium hardness (amount of calcium) c. Magnesium hardness (subtracting calcium hardness from total hardness) d. Permanent hardness (by calcium and magnesium sulfates, chlorides) e. Temporary hardness (by calcium ions and bicarbonate ions) In this application sheet, the method of determination of total hardness titrating with EDTA titrant by photometric titration is introduced.