Introduction to Ultra Pure Water for Laboratory Use

Overview of Ultra Pure Water for Laboratory Use

Ultra pure water used in laboratories generally has high requirements for water quality. According to different application scenarios, it can be divided into three levels of water: first level water, with a resistance requirement greater than 10M Ω. cm (conductivity less than 0.1us/cm), mainly used for analysis tests with strict requirements, including tests with particle requirements. Water for high-pressure liquid chromatography analysis. First grade water is commonly used, and second grade water is distilled by quartz equipment or treated with a mixed bed of reverse osmosis and ion exchange, and then treated with 0.2 μ M microporous filter membrane filtration is used to produce. Secondary water, with a resistance requirement of more than 10M Ω (conductivity below 0.1us/cm), is mainly used for inorganic trace analysis and other experiments, such as atomic absorption spectroscopy analysis water. Secondary water can be produced by multiple distillation, reverse osmosis, and ion exchange methods. Third grade water is used for general chemical analysis experiments. Third grade water can be produced by distillation or ion exchange methods.

Using EDI modules as post-processing

The electro deionized ultra pure water treatment equipment adopts a reverse osmosis host with EDI

Electrodeionized ultra pure water treatment equipment

Common methods for preparing laboratory water

1. Distilled water

The most commonly used type of pure water in laboratories, although the equipment is cheap, is extremely energy and water consuming, and the speed is slow, and its application will gradually decrease. Distilled water can remove most of the pollutants in tap water, but volatile impurities such as carbon dioxide, ammonia, silicon dioxide, and some organic compounds cannot be removed. Fresh distilled water is sterile, but bacteria can easily multiply after storage; In addition, the storage container is also very particular. If it is a non inert substance, ions and the plastic substances in the container will precipitate and cause secondary pollution.

2. Deionized water:

The application of ion exchange resin to remove anions and cations from water is a traditional process for producing pure water that has been used for a long time. After treatment, a certain purity of ultrapure water can be obtained. However, soluble organic matter still exists in the water, which can contaminate the ion exchange column and reduce its effectiveness. Storage of deionized water can also easily cause bacterial proliferation.

3. Reverse osmosis water:

The principle of its generation is that water molecules, under pressure, pass through the reverse osmosis membrane to become pure water, and impurities in the water are intercepted and discharged by the reverse osmosis membrane. Reverse osmosis water overcomes many drawbacks of distilled water and deionized water. The use of reverse osmosis technology can effectively remove impurities such as dissolved salts, colloids, bacteria, viruses, bacterial endotoxins, and most organic matter from water.

4. Ultra pure water:

The standard is a water and electricity resistance of 18.2M Ω - cm. The latest technology for producing ultrapure water often uses reverse osmosis with ion exchange mixed bed or reverse osmosis with electrodeionization (EDI), which is more economical and environmentally friendly compared to the former.