2. Water consumption
3. Water quality. The national laboratory standard water has three kinds of water quality: 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, which is used to clean glassware. The second is first-class water, which is mainly used for chemical analysis such as liquid phase and atomic absorption or precision instrument analysis. Customers should choose the grade of ultra-pure water machine according to the actual water quality demand. Ultra-pure water machines with tap water as water source have two water outlets (two kinds of water quality), one is pure water, that is, tertiary water; The second is the first-class water, that is, ultra-pure water (strictly speaking, the resistance of the first-class water is greater than10mΩ. Cm, while the resistance of ultrapure water is greater than 18mω. cm)。 Most customers don't know their water quality requirements. Although the relevant national departments have various water quality standards, there is no complete quantitative index for specific experimental projects or instrument analysis water, and it is often found that the water quality is not up to standard after purchasing ultra-pure water machines. According to experience, you can follow the following three principles of purchasing, which are corresponding.
1. Current water source: If your current water consumption is qualified, you can also tell us the source of purified water, and our technicians will recommend the corresponding specifications and models according to the situation.
2. Experimental content: It is divided into inorganic experiment and organic experiment. Inorganic experiment only needs water with resistance greater than18mΩ. Cm, and organic experiments usually need to remove organic matter from water, so except the resistance is greater than18mΩ. Cm, but also the index of total organic carbon. If it is a biological experiment, it is necessary to remove bacteria from the water.
3. Instrument type: customers can choose ultra-pure water machine according to the type of instrument used. The resistance of liquid water is greater than 18mω. cm； ; Organic matter should be removed; As long as the water used for atomic absorption, atomic fluorescence and environmental monitoring instruments is greater than 18mω. cm； In addition, the resistance of water used in life science instruments such as PCR is greater than 18mω. Cm, it needs disinfection, except for organic matter.