Short answer, type 1 water is purer than type 2, but there is a lot more to take into consideration before specifying one.
As the use of instruments requiring specific qualities of water increases, laboratories are moving away from the traditional Type 1, 2, and 3 specifications and toward a set of guidelines which are laid out in the Clinical and Laboratory Standards Institute (CLSI) G40-A4-AMD guidelines.
These include:
- Clinical Laboratory Reagent Water (CLRW)
- Special Reagent Water (SRW)
There are three main bodies who have had influence in establishing water standards over the years, these are CLSI with the G40-A4-AMD guidelines (mentioned above), ISO with 3696:1987, and ASTM which uses D1193-06.
All of these standards vary in some way and can cause confusion when a grade is specified without directing which organisation’s standard is being referenced. This makes it essential to ensure that your laboratories unique requirements are accounted for when specifying what level of purification you require.
Clinical Laboratory Reagent Water (CLRW)
For reference a standard Purific purification system would fall into the CLRW range with the following properties and is comparable to a traditional Type 2 in water quality. This grade water comes from the regular specifications for blood chemistry analysers requiring this high purity water.
- ≥10 MΩ/cm at 25 °C Resistivity
- <10 CFU/mL
- TOC <500 mg/g (ppb)
- 0.22 µm absolute final filtration near or at the final output stage of the purification system.
Special Reagent Water (SRW)
Special reagent water is used when different quality water to CLRW s required. In essence it is similar to CLRW but may have more or less stringent parameters added to meet the requirements of the laboratories procedures.
Some applications include
- Trace organic analysis.
- DNA and RNA testing.
- Trace metal analysis.
- Cell/tissue/organ culture and florescent antibody detection of microorganisms.
- Low CO2 water.
Feel free to call one of our friendly team to ask further questions should your laboratory require a specific grade water on 1800 573 316 or send an email to service@purific.com