Pure and Ultrapure Water Treatment: Water Qualities
Which Ultrapure Water Qualities are there?
Germany and Europe - Drinking Water Ordinance and European Pharmacopoeia
In Germany, the classification into different ultrapure water qualities is based on the German Drinking Water Ordinance (TrinkwV). In Europe there is the European Pharmacopoeia, according to which the ultrapure water quality levels are divided. Various parameters are included in the classification.
The European Pharmacopoeia describes the following terms:
- AP: Aqua Purificata
also referred to as deionized water (fully desalinated water) or PW (purified water) - HPW: Highly Purified Water
Pharmaceutical water in WFI quality, but made with membrane technology - WFI: Water for Injection
Defined water quality for sterilized final containers; mostly made by distillation
Parameters | TrinkwV | Feed Water DIN 285/58950 | AP | HPW | WFI |
---|---|---|---|---|---|
Conductivity | 2.790 µS/cm at 25°C | <1,1 µS at 20°C | <4,3µS at 20°C | <1,1 µS at 20°C | <1,1 µS at 20°C |
Bacteria | 0 | <100 KBE/ml | < 10 KBE/100ml | < 10 KBE/100ml | |
Endotoxins | < 0,25 EU per ml | < 0,25 EU per ml | < 0,25 EU per ml | ||
TOC | without abnormal change | <500 ppb | <500 ppb | <500 ppb | <500 ppb |
Nitrate | 50 mg/l | <0,2 ppm | |||
Heavy metals (especially Pb) | 0,010 mg/l | <0,1 ppm | <0,1 ppm | ||
pH | 6,5 - 9,5 | 5,0 – 7,0 | |||
Silicon (SIO2) | < 1 mg/l |
International - ASTM
Internationally, it is divided into different ultrapure water qualities according to the American Society for Testing on Materials (ASTM). Here, too, various parameters are included in the classification.
Parameters | Typ I | Typ II | Typ III | Typ IV |
---|---|---|---|---|
Conductivity | 0,056 µS/cm | 1,0 µS/cm | 4,0 µS/cm | 5,0 µS/cm |
Electrical Resistance | 18 MΩ-cm | 1.0 MΩ-cm | 0,25 MΩ-cm | 0,2 MΩ-cm |
TOC | 10 ppb | 50 ppb | 200 ppb | - |
Sodium | 1 ppb | 5 ppb | 10 ppb | 50 ppb |
Chloride | 1 ppb | 5 ppb | 10 ppb | 50 ppb |
Silicate (Silicon) | 3 ppb | 3 ppb | 500 ppb | - |
Bacterial Count (KBE) | 1/100 ml | 10/100 ml | 1000/100 ml | |
Endotoxine (EU/ml) | < 0,03 | < 0,25 | N.A. | |
Technologies | Ultra Pure Water System | Pure Water System | Reverse-Osmosis EDI |
Pharmacopeia-Norms: EP and USP
Pharmacopeia-Norms are separate standards from the authorities in Europe, USA and Japan for different materials, e.g. water for medical use.
Parameters | EP | USP |
---|---|---|
Spec. Conductivity | <4,3 µS/cm at 20 ºC | <1,3 µS/cm at 25 ºC |
TOC | <500 µg/l C | <500 µg/l C |
Nitrates | <0,2 ppm | - |
Germ count (guideline CFU/ml) | <100 KBE/ml | <100 KBE/ml |
Particle Content | 0,2 µm Filter | - |
Heavy Metals | <0,1 ppm | - |
ISO 3696:1987
Water for analytical laboratory use, requirements and testing
Parameters | Grade 1 | Grade 2 | Grade 3 |
---|---|---|---|
Conductivity (µS/cm at 25 °C, max.) | 0,1 | 1 | 5 |
pH-Value at 25 °C | - | - | 5,0 - 7,0 |
Oxidizable matter, oxygen content (mg/l, max.) | - | 0,08 | 0,4 |
Absorbance at 254 nm and a length of 1 cm (Absorbance Units, max.) | 0,001 | 0,01 | - |
Residual after evaporation when heated to 110°C (mg/kg, max) | - | 1 | 2 |
Silicon content (mg/l, max.) | 0,01 | 0,02 | - |