Applications of Deionised Water in Different Laboratory Settings by Jo Alelsto

Applications of Deionised Water in Different Laboratory Settings

by: Jo Alelsto

One of the most important uses of deionised water is in the laboratory. May it be a chemical, microbiological, genetics and molecular biology, medical or tissue culture laboratory, water is an indispensable item inside the lab.

These are areas of science which call for the one of purest form of water available known as deionised water.

The process involved in deionising water is long and painstaking, ensuring that the end product is uncontaminated and free from impurities. Deionised water undergoes a five step process of filtration: organic trap, twin bed deionizer, mixed bed resin, ultra violet treatment, and filtration through a 0.02 micrometer pore size.

Organic impurities are filtered out first then the ions (cations and anions) are removed. At this point, water is deionised. However, there are still other impurities found in water and so water is subjected to an ultraviolet treatment to kill microorganisms. Another filtration through a mixed bed resin is used to remove any remaining impurities. Finally, water is filtered using a filter of a 0.02 pore size.

The end product is ideal for use in the laboratory wherein every single item must be in their purest form to come up with accurate results.



In the chemistry laboratory, deionised water is used in preparing glass wares, utensils, and other tools. Normal or tap water usually has impurities present, such as fluorine and chlorine, which can influence the results of your chemistry experiments.

Deionised water is used to rinse glass wares, laboratory tools, as well as small and large apparatus used in the microbiological testing. Deionised water is also used as a solvent in media preparation and other microbiological procedures requiring water. Everything must be sterile inside the microbiology lab and every process must be done asceptically.

In a molecular biology lab, deionised water needs to undergo further filtration to be DNase or RNase-free to be deemed usable in this setting. Molecular biology and genetic experiments are particularly sensitive to impurities because of the need for an accurate and exact set of results. The standard error must be very slim indeed.

The same goes for a tissue culture laboratory, everything must be sterile and the processes must be asceptic. Deionised water is also used in media preparation as well as in the set-up of the needed items and equipment.

A medical laboratory processes clinical specimen of patients to obtain more information on his/her health. The physician can then make a better evaluation of the patients health based on the results of a urine sample or a blood sample, for instance. Therefore, careful handling and preparation of the samples and the whole test are performed to ensure that the results are accurate. The proper diagnosis of a patients health condition lay heavily on the results these tests will show.

Deionised water, however, must meet the standards for each type of laboratory since each also has a different need. Nonetheless, deionised water is already of a higher grade than tap water and it can be used for various laboratory preparations and procedures.



Aside from its crucial uses in the laboratory setting, deionised water is also used extensively in the food processing, pharmaceutical, cosmetics, electronics, and automotive industries. It has even found its use into your local carwash. Water is indeed a central ingredient in everything we do.