Several organizations have set quality standards for purified water based on intended use. Several organizations have set quality standards for purified water based on intended use. Among them are the following:
ASTM (American Society for Testing and Materials)
NCCLS (National Committee for Clinical Laboratory Standards)
ISO International Organization for Standarization
EP y USP (Pharmacopea Europea y Pharmacopea Americana)
(ASTM) D1193-91American Society for Testing and Materials
Standard Specification for Reagent Water
|
Parameter |
Type I |
Type II |
Type III |
Type IV |
|
Electrical Conductivity Max. (µS/cm @ |
0,056 |
1,0 |
4,0 |
5,0 |
|
Electrical Resistivity (MΩ-cm @ |
18,2 |
1,0 |
0,25 |
0,2 |
|
pH at 25ºC |
- |
- |
- |
5,0 - 8,0 |
|
TOC máx. (µg/L) |
10 |
50 |
200 |
n/a |
|
Sodium máx. (µg/L) |
1 |
5 |
10 |
50 |
|
Total Silica max. (µg/L) |
3 |
3 |
500 |
n/a |
|
Chlorides max. (µg/L) |
1 |
5 |
10 |
50 |
|
Endotoxins IU/ml |
< 0.03 |
< 0.25 |
- |
- |
|
Parameter |
Type I |
Type I I |
Type III |
|
Bacteria (CFU/ml) |
< 10 |
< 1000 |
NA |
|
pH |
NA |
NA |
5,0 - 8,0 |
|
Resistivity (MΩ.cm @ |
> 10* |
> 1 |
> 0,1 |
|
SIlica (mg/L) |
< 0,05 |
< 0,1 |
< 1 |
|
Total Solids (mg/L) |
0,1 |
1 |
5 |
|
Total Oxidisable Organic Carbon (mg/L) |
< 0,05 |
< 0,2 |
< 1 |
|
Particulate matter |
< 0.2 µm |
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|
* Type I resistivity is measured in line |
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ISO International Organization for Standardization. ISO 3696.
Water for analytical laboratory use - Specification and test methods
|
Parameter |
Degree 1 |
Degree 2 |
Degree 3 |
|
pH at 25ºC |
N/A |
N/A |
5,0 a 7,5 |
|
Electrical conductivity (µS/cm |
0,1 |
1,0 |
5,0 |
|
Oxidizable matter. Oxigen (O) (content mg/L. máx) |
N/A |
0,08 |
0,4 |
|
Absorbance at 254 nm and 1 cm optical path lenght. Absorbance units, máx. |
0,001 |
0,01 |
Not specified |
|
Residue after evaporation at |
N/A |
1 |
2 |
|
Silica content (SiO2) (mg/L., máx ) |
0,01 |
0,02 |
Not specified |
Some Pharmacopoeias have set requirements for water. Among the best known are the USP (United States Pharmacopoeia.) and EP (European Pharmacopoeia). Pharmacopoeias also establish purity criteria (microbiological and pyrogen content) for sterile water and water for injection.
|
Parameter |
EP |
USP |
|
Nitrates |
<0,2 ppm |
- |
|
Heavy Metals |
<0,1 ppm |
- |
|
TOC |
<500 µg/L C |
<500 µg/L C |
|
Conductivity |
<1,1 µS/cm a 20ºC |
<1.3 µS/cm a 25ºC |
|
Bacteria |
<100 CFU/ml |
<100 CFU/ml |