There are a variety of different types of purified water available in the market today. They all claim to be the best for research and for experimentation, however there are some preferences amongst scientists and industrial researchers and production managers to choose certain types of water that is suitable for certain types of experiments or processes. Here is a rundown of a few types of water and their properties.

1. De-ionized Water

Also known as demineralized water, deionized water is water that has gone through the process of deionization in a deionizer. This instrument uses negative and positive charges to extract ions from within water to render it pure. A current is allowed to flow through the water and as it does so, the ions stick to the surfaces of the mixed bed resins and conductivity decreases.

This process, among many others, is used to purify water for pharmaceutical companies. It is usually used to removed heavy metal ions and heavy negative ions such as sulfate ions and nitrate ions and chloride ions.

This water is very good for research, but further purification may be required if you’re going for ultra purity, such as through more chemical dosing and distillation. 

2. USP Grade Water

USP grade water  passes certain grade tests set by the USP system, which is the United States Pharmacopeial Convention system of standards. They include pH requirements of 5.0 to 7.0, and certain mg/l ratings like 0.5 for Chloride, 1.0 for sulfate, 0.03 for Ammonia, and 5.0 for Carbon dioxide.

They also require bacterial concentrations of 100 CFU/ml and Endotoxin impurities of up to 0.25 EU/ml.

Since these standards are adhered to for pharmaceutical manufacture and testing, they are of the highest standards of purity and this water can be used for research without any hesitation.

3. HPLC Grade Water

HPLC grade water is water stands for High Performance/High Pressure Liquid Chromatography water. It is so named because the purity of this water is related to a minimal background or signal interference for the mentioned technique. It is available with most chemical suppliers and has some specific properties. It has a specific conductivity of 16 to 18, it is maintained by the ELGA water machines (which supply purified water for research and development, healthcare and clinical research) and is filtered through 0.22 micron filters to clear it of any particulate matter.

It has a very low Ultraviolet light absorbance and is sealed in a very inert atmospheric packing (often nitrogen), so you can bet that it’s completely free of any contaminants that appear through oxidation or spontaneous reaction.

This is quite high grade water for research and since it is primed for the HPLC technique which uses the flow rate of certain particles and substances to separate them from a mixture, It can be considered quite appropriate for research.

Note: All 3 types of grades can be used for research purposes. it's about finding the specifications that you require. Please contact us  at [email protected] if you need help or have any questions on finding the one that's right for your lab. 


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