Compared with electric distilled water or buying water outside, the ultrapure water machine in the laboratory provides us with a lot of convenience and benefits, which has been recognized by the majority of chemical analysts, and this instrument is the basis of the laboratory Equipment, although many technicians are using ultra-pure water machines, but everyone does not know enough about ultra-pure water machines, so people often have some misunderstandings in purchasing.
one. water consumption
The water production capacity of ultrapure water machines currently on the market is generally 5-45 liters/hour. Customers should choose the specifications of the ultrapure water machine according to the actual water consumption, and generally follow the principle of 2 times the relationship. If the water consumption is 20 liters/day, choose a machine with a specification of 10 liters/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 water consumption is large, you need to purchase a larger pure water bucket, otherwise the water production will not be able to keep up.
two. 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.; 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 kinds of water quality), one is pure water; ohms, 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.
three. 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.
