At present, the types of pure water can be divided into the following grades:
Pure water, distilled water, deionized water, laboratory grade I, II, III pure water and ultrapure water.
Standard ASTM and ISO 3696, laboratory grade II water and deionized water have the same quality requirements.
1. Pure water
Pure water is a general term that can be produced by a single weakly basic anion exchange resin, reverse osmosis or single distillation. At present, it is basically produced by the reverse osmosis method, which has the lowest purification level. Usually the conductivity is between 1-50 μs/cm. If you want to obtain extremely high-purity high-purity water or ultra-pure water, you still need to remove the electrolyte (soluble inorganic matter) from the mixing process. Bed, EDI and other methods. Typical applications include glassware cleaning, autoclaves, constant temperature and humidity chambers and water for washing machines.
2. Laboratory grade III pure water-Two- stage reverse osmosis pure water machine
Conductivity ≤5.0μs/cm, PH: 5-7. Typical applications include glassware cleaning, autoclaves, constant temperature and humidity experimental chambers, water for cleaning machines, preparation of reagents, etc. It is generally prepared by single distillation or double-stage reverse osmosis method.
3. Laboratory grade II pure water-Deionized water
There are still non-ionizable non-electrolytes (soluble organic matter) in deionized water, such as ethanol, heat sources, and relatively high bacterial contamination levels, so deionized water generally cannot be used as water for injection, but it can meet most needs, such as cleaning , prepare analysis standards, prepare reagents and dilute samples, etc.
At present, ions in water are mainly removed through RO membrane (reverse osmosis method) and mixed bed resin (ion exchange method).
Since the ions produced by ionization of electrolytes (soluble inorganic substances) dissolved in water can increase the conductivity of water, the purity of deionized water is naturally measured by conductivity or resistivity. Its conductivity is usually between 1.0-0.1μs/cm. between.
4. Laboratory grade I Water-Ultrapure water
This level of pure water is close to the theoretical purity limit in terms of resistivity, organic matter content, particle and bacterial content. It is pre-purified through ion exchange, RO membrane or distillation, and then refined through nuclear-level ion exchange to obtain ultrapure water. Usually the resistivity of ultrapure water can reach 18.2MΩ.cm, TOC<10ppb, it can filter out particles of 0.1μm or smaller, and the bacterial content is less than 1CFU/ml.
Ultrapure water is suitable for the needs of a variety of precision analysis experiments, such as high performance liquid chromatography (HPLC), ion chromatography (IC) and ion capture mass spectrometry (ICP-MS). Low-pyrogen ultrapure water is suitable for biological applications like eukaryotic cell culture. Ultrafiltration technology is often used to remove large molecular bioactive substances such as pyrogens (results <0.005IU/ml) and undetectable nucleases and proteases.
LABOAO Laboratory pure water machine and Laboratory Ultrapure water systems
At present, our Laboratory pure water machines and Laboratory Ultrapure water systems can produce laboratory grade I water, with multiple models such as 10-120L. One-click operation is convenient and fast, and different water production volumes can meet customers' water needs. Water machines with richer functions and more exquisite appearance are also being developed, so stay tuned!