Table showing analysis of demineralized water
Pure water can be prepared by any one of the methods as per pharmaceutical grades of water but the only condition is that it must satisfy USP standards. The pure water thus obtained is used in producing USP products.
USP24
Has completed versions of pharmaceutical water monographs
1752-1754 and the general chapters
TOC, water conductivity
1927-1929, and
Water for pharmaceutical purposes
p. 2154-2163
pH
5.0 - 7.0
Chloride (mg/l)
0.5
Carbon Conductivity
1.3 TS / cm @ 25° 1.1 TS / cm @ 20°
Ammonia (mg/l)
0.03
Calcium (mg/l)
1.0
Table: DM specifications as per USP
Depending upon the extent of purity of water there are three grades of reagent grade water:
Grade 1: In test methods such as trace analysis which require great accuracy and maximum precision. By distillation of feed water, reagent water can be made.
Grade 2:It is used where the major concern is that organic impurities should not be present for example in laboratories. It is not used for analysis in medicine and biology.
Grade 3: In washing of glassware, where more quantity of water is needed but of less purity.
S.no
Characteristic
Requirement
Method, Ref No
Grade
1
Grade 2
Grade 3