Which level of reverse osmosis and ion water is higher? What is pure? What are the grades of water?

Most pH = 7
The water is a reagent that is often ignored but vital to laboratory. What kinds of laboratory water is there? What level can you reach? What are the requirements for water for different experiments? These issues have some vague concepts for me before. A few days ago, I participated in the tender of the school's pure water device, read some relevant information, and preliminarily learned about the relevant knowledge. Now I will share it with you. I translated from foreign language information, and I hope you have criticized everyone. These materials also include the essence of FREECELL comrades in this section, and thank you here!

The types of water commonly used in laboratories:

1, distilled water:
Extreme energy consumption and water and slow speed, the application will gradually decrease. Differential water can remove most of the pollutants in tap water, but volatile impurities cannot be removed, such as carbon dioxide, ammonia, silicon, and some organic matter. Fresh distilled water is sterile, but the bacteria are easy to reproduce after storage. In addition, the stored container is also very particular. If it is a non -inert substance, the shape of the ion and container will precipitate secondary pollution.

2. Deionized water:
The ion exchange resin to remove the ablation and cations in the water, but there is still soluble organic matter in the water, which can pollute the ion exchange column to reduce its effect. After removal water is stored, it is easy to cause bacteria to reproduce.

3, Reverse Osmosis Water:
The principle of its generation is that water molecules become pure water through the influence of stress, and the impurities in the water are intercept the reverse osmosis membrane. discharge. Reverse seepage water overcomes many disadvantages of distilled water and ion water. Using reverse osmosis technology can effectively remove impurities such as dissolved salt, germ, bacteria, viruses, bacterial internal toxins, and most organic matter in water. The quality of anti -seepage has a great impact.

4, Ultra-Pure Grade Water:
The standard is that the hydration rate is 18.2MΩ-CM. However, ultra -pure water is not the same in terms of TOC, bacteria, endoxin and other indicators. It is necessary to determine according to the requirements of the experiment. For example, cell culture has requirements for bacteria and endotoxin, and HPLC requires TOC to be low.

The common indicators for evaluation of water quality:

1, resistivity ():
The indicator of hydrophobic performance in the laboratory, the unit is MΩ-CM, with the water, with the water, with the water, with the water, with the water, with the water The reduction of the resistance of the internal inorganic ions will gradually become larger, and the standard of the ultra-pure water in the laboratory: The resistivity is 18.2MΩ-CM.

2, total organic carbon (TOC):
The concentration of carbon in water, reflects the content of organic compounds in the water, the unit is PPM or PPB.

3, endotoxin:
The fat polysaccharides of the Gram -negative bacteria of Gram -negative bacteria, also known as "thermal Yuan", unit CUF/ML.

The inlet water indicator of reverse osmosis 7l3J n#x#x- |) d T
The general specification is 5--40 degrees, and the minimum must not be lower than zero.
pH value: 2--11 (preferably 4--9)
SDI: ≤4 m0h u "x ~ r" @) Z. {
COD: ≤1.5mg/L
Residual chlorine: ≤0.5mg/L
Total iron: ≤0.1mg/L | Power plant boiler, turbine, electricity, water treatment The technical exchange of the thermal power industry D E
`5t m s¬o1b
:: ≤0.05mg/L-W A K1K, G

Reverse infiltration water is pure water,
The soft water out of ion water.