Detailed purchase method of laboratory ultra-pure water machine [dry goods]

At present, the laboratories of universities and research institutions basically use ultrapure water machines instead of distilled water machines to make water, and units above the urban level in the eastern region have reached the popular level. Such as: Environmental Monitoring Station, Food and Drug Inspection Institute, Center for Disease Control, Quality Inspection Institute, Agricultural Soil and Fertilizer Station, etc. The laboratories of many enterprise units also use ultrapure water machines instead of distilled water machines to produce water, especially in the eastern, central and western regions, where the efficiency is higher.

Compared with electric distilled water or outdoor purchased water, laboratory ultrapure water machines provide more practical problems and convenience. This has been recognized by most chemical analysts, but after all, this instrument is the basic equipment of the laboratory. Although many technicians are using ultrapure water machines, they still don't know much about ultrapure water machines, and there are often misunderstandings when purchasing. How to choose the ultrapure water machine suitable for this machine, please refer to the following content, I hope it will be helpful to you.

1. Water consumption

At present, the water production capacity of ultrapure water machines is generally 15 liters/hour, 30 liters/hour, 63 liters/hour, 94 liters/hour, 125 liters/hour, and the larger industrial type has 250 liters/hour hour, 500 liters/hour, the customer should choose the specifications of the ultrapure water machine according to the actual water consumption, and generally follow the principle of 3 times the relationship. If the mercury is 45 liters per day, choose a machine with a specification of 15 liters per hour. If the specification is too small, the consumables of the ultrapure water machine will be consumed quickly. If the specification is too large, it will cause waste. If the concentrated mercury is large, you need to buy a larger pure water bucket, otherwise the water production will not be able to keep up.

2. Water quality

National laboratory standard water has three water qualities: first-class water, second-class water, and third-class water, but most laboratories can use two kinds of water quality, one is third-class water, such as distilled water, used for cleaning glassware, etc.; two It is first-class water, mainly used for chemical analysis or precision instrument analysis such as liquid phase and atomic absorption. Customers should choose the grade of ultrapure water machine according to the actual water quality requirements. The ultrapure water machine with tap water as the water source has two water outlets (two water qualities), one is pure water, that is, third-grade water; the other is primary water, that is, ultra-pure water (strictly speaking, primary water The resistance of the ultrapure water is greater than 10 megohms, while the resistance of ultrapure water is greater than 18 megohms).

Most customers are not clear about their water quality requirements. Although the relevant national departments have various water quality standards, they do not have complete quantitative indicators for specific experimental projects or instrumental analysis of water use. Water quality is often discovered after purchasing an ultra-pure water machine. not to standard. According to experience, you can follow the following purchasing principles, corresponding to it.

1. Experimental content

There are inorganic experiments and organic experiments. Inorganic experiments only need water quality with a resistance greater than 18 megohms, while organic experiments usually need to remove organic substances in the water. Therefore, in addition to resistance greater than 18 megohms, an indicator of total organic carbon is also required. If it is a biological experiment, the bacteria in the water should be removed.

2. Instrument type

Customers can choose ultrapure water machines according to the type of equipment used. The resistance of the liquid phase water is greater than 18 megohms; and organic matter must be removed; the water for atomic absorption, atomic fluorescence and environmental monitoring instruments is greater than 18 megohms; the water for life science instruments such as PCR needs to be sterilized in addition to the resistance greater than 18 megohms. In addition to organic matter, in addition to heat sources.

3. Current water source

If the current water used by the customer is qualified, the ultrapure water machine manufacturer can also be notified of the source of the pure water, and its technicians will suggest the corresponding specifications and models according to the situation. The above three principles are based on actual application experience and can be used for reference. However, for accurate model selection, try to provide detailed water quality parameters, such as electrical resistance, trace elements, bacteria, and total organic carbon levels.

3. Raw water quality

When purchasing an ultrapure water machine, the customer must provide the manufacturer with the water quality of the raw water, such as a lot of sediment, high hardness, groundwater, etc. The process of the ultrapure water machine is determined according to the quality of the raw water. Many, need to add pretreatment device, high hardness, need to add softening device, high salt content, use two-stage reverse osmosis process, etc. If you choose an ultrapure water machine with pure water as the water source, you only need to provide the water quality requirements and water consumption.

4. The main purpose of pure water

• Final cleaning of labware

• Buffer, chemical reagent preparation water

• Microbial culture medium preparation water

• Pure water for hydrogen generators, indoor humidifiers, and autoclaves

• Drinking water for humans or experimental animals, etc.

Five, the main purpose of ultrapure water

• Animal and plant cell culture water

• Water for various medical biochemical instruments, analyzers, and hemodialysis instruments

• Analytical reagents and pharmaceutical preparation dilution water

• Physiological, pathological, toxicological experiment water

• Purified water and high-purity water used in hospitals, pharmaceutical preparation rooms and central laboratories

• water for atomic absorption spectroscopy

• test tube baby water

• Water for various effective liquid chromatography and ion chromatography

• Various other laboratory water and medical water