Why is EDI pure water more suitable for acid-base titration than RO pure water?

[This article is the original article of Lefeng RephiLe company, please indicate the reprint, offenders. 】

 

Acid-base titration is one of the most basic analytical chemistry experiments, and you may be exposed to it during high school. But the choice of water for titration is not understood by every experimenter. Some customers have said that when using the water produced by reverse osmosis RO pure water system for titration analysis, the error is too large, resulting in failure of the experiment, which is considered to be a problem in the pure water system.

The fact is - a good RO water machine, inexplicably "back pot"!

Indicators are often used in acid-base titration assays to determine the endpoint of the titration. A highly sensitive indicator that changes color when the pH is slightly changed, and visually observes the color change to determine the end point of the titration. pH is a critical parameter throughout the titration. As pure water with a matrix of titration solution, the effect on titration should not be underestimated.

Reverse osmosis technology has different rejection rates for different impurities. It is not difficult to understand that pure water obtained by RO pure water mechanism is related to the influent conditions. Generally speaking, RO pure water is acidic and has a wide pH range. This is because the dissolved CO _{2 in the} tap water cannot be removed. Carbon dioxide has the following dissociation equilibrium process in water:

CO ₂ + H ₂ O ↔ HCO ₃ ^- +H ⁺

CO ₂ + H ₂ O ↔ 2H ⁺ +CO ₃ ^2-

Since CO ₂ is equivalent in size to water molecules, RO membrane cannot remove gaseous carbon dioxide, but HCO ₃ ^- and CO ₃ ^2- can be largely trapped, causing the above two chemical equilibriums to move to the right, and H+ ions in pure water producing water. The concentration will increase, so the RO water will show acidity.

1. The content of ionic impurities in the influent water is unstable. After being intercepted by the RO membrane, the content of ionic impurities in the produced water has a certain range of variation, which has an effect on the pH value of the produced water;

2. The change in the carbon dioxide content in the influent environment causes the pH of the produced water to fluctuate widely.

The dependence of RO water on the influent water quality will inevitably affect the titration reaction, interfere with the pH value of the end point, and bring difficulty to the endpoint judgment, resulting in a large experimental error, which is obviously not suitable.

The pure water equipment with EDI module is based on the RO purification technology and adds continuous current deionization EDI module. EDI is the best replacement technology for the traditional ion exchange mixed bed process. With the unique characteristics of EDI purification technology, the pure water meter with EDI module removes impurities from tap water more thoroughly, and the water quality is higher and not subject to The water quality is more stable due to the influence of influent water quality. Such a pure water solution has less uncertainties in the titration experiment, and is naturally more advantageous than RO pure water, and is more suitable for acid-base titration.

When it comes to the EDI pure water system, you can recommend the new Genie E laboratory water purifier from Lefeng. Lefeng is the first supplier of pure water equipment in EDI laboratory in China. The new generation Genie E is tailor-made for laboratory EDI water supply. It is equipped with ionPure EDI module and built-in high quality RO membrane, which can remove more than 99% of water. Molecular impurities and more than 95% of ions. If the laboratory still needs ultra-pure water, you can choose Genie G intelligent integrated ultra-pure water system (can prepare EDI and ultra-pure water, one machine and two water). Genie G not only meets titration, media preparation, pH solutions and buffers, but also provides pyrogen-free, nuclease, and bacteria ultrapure water for biochemical analysis and molecular biology, providing a more comprehensive service for laboratory users. The Genie laboratory pure water system adopts the most advanced design concept and adopts high-standard standardized production, which will give users the feeling of not using imported high-end products.

Based on the water needs of different laboratories, Lefeng also provides customers with thoughtful and meticulous water solutions to help users conduct high-quality and high-quality experiments.

Lefeng Keywords: pure water, titration, EDI, Shanghai Lefeng, RephiLe, Genie water purifier, Super-Genie water purifier

About Shanghai Lefeng Biotechnology Co., Ltd.

Shanghai Lefeng Bio is specialized in the research, development, design and manufacture of high-end water purification and laboratory separation and purification products, and is committed to providing cutting-edge, high value-added innovative products for life sciences and biotechnology. The Lefeng product line includes laboratory pure water systems, Millipore pure water compatible consumables and laboratory separation and purification filtration products. Established ten years ago, Lefeng has established its own brand RephiLe (Ruifeng), with more than 30 patents and multiple software copyrights. Products are sold to nearly 90 countries and regions around the world. For more information on RephiLe products, please visit: Le Feng official website

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