Page 104 - Pharmaceutical Analytical Chemistry III
P. 104
DETERMINATION OF WATER HARDNESS:
❖ EDTA method
* For total Ca and Mg contents :
Buffer water sample to pH 10 using
NH4Cl/NH4OH, then titrate with st. EDTA using
E.B.T. indicator.
* For calcium hardness alone :
Buffer to pH 12, titrate against st. EDTA using
murexide indicator.
* Mg hardness is measured by difference.
