What are the differences between the water produced by a pure water machine and distilled water, deionized water, and RO reverse osmosis water?
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This post was last edited by ldzmea on 2019-4-3 at 16:05. Distilled water should be used to prepare solutions in the laboratory. Can water produced by a water purifier be used for preparing solutions? Which of these two types of water has a stricter standard for purity in terms of water purification, and how do the quality standards of RO reverse osmosis water compare to those? Seek an authoritative explanation; do not use Baidu or similar.
I think distilled water is just a relatively outdated method of water purification; nowadays, water purifiers or RO systems produce water that is cleaner than distilled water, right?
Generally, grade 3 water is used for preparation. Distilled water can meet the requirements of some reagents, while ultra-pure water is needed for tests at the trace level; this ultra-pure water corresponds to grade 1 water produced by water purifiers. Water purifiers use filtration, RO resin, and ultraviolet lighting for sterilization, resulting in a resistivity of 18.25, which is certainly better than that of distilled water
That’s because your understanding of distilled water is insufficient. For the analysis of many highly pure substances, purified water prepared by distillation is the best choice. In particular, subboiling distillation achieves a level of purification that other methods for producing pure water cannot match.
Resistivity is not the only indicator of pure water purity; in addition, the content of certain organic impurities can be high, yet the resistivity can remain low.
Generally, the resistivity of water that has passed through RO and EDI reaches 18.25 M, and there are no organic substances left in it as well. Is the water obtained by distillation completely free of organic substances? What about those substances that are azeotropic with water? How are they separated? In my opinion, the standard for distilled water can certainly be determined by its resistivity. Generally, the resistivity of water obtained through distillation does not reach the megohm range; compared to water that has been purified using EDI after reverse osmosis, its purity is not comparable at all. Am I correct?
The quality of high-purity water is evaluated by combining resistivity and TOC.