Why do you need pure water in a laboratory?

Pure water plays an important role in scientific experiments, it can ensure the accuracy and repeatability of experiments. Pure water is widely used in scientific experiments and purified water is essential for glassware cleaning, water bath heating, autoclave water filling, steam generator, etc.

Why not tap water?

Tap water has far too many contaminants to be used in laboratories or for scientific purposes. Impurities, elements and compounds in amounts as small as one part per trillion, can influence results in many research experiments. Heavy metals and dissolved organics, commonly found in tap water, are particularly damaging to life science research. Some scientific applications such as High Performance Liquid Chromatography (HPLC) use detector base lines for calibration, and these require ultra pure water completely free of any impurities so that the results are the same in every situation. The water must especially be free of any elements that are being measured.

Because water purity is so important, several professional organizations have established water quality standards.

NCCLS specifies three types of water--I, II, and III--and water intended for Special Purpose use.

Water Purity Definitions

According to the standards of ASTM, several factors define the water purity in the water purification system for laboratories. These standards are well marked by the scientists for their versatility and accuracy.

Conductivity

Conductivity is defined as the conductance of electricity with ease through the water. Perfect pure water should have a low level of conductance. In this sense, type III and type IV pure water is tested. More conductance means more ions in the water which can conduct electricity. So, it is advised to measure the conductivity of pure water before approaching any laboratory water purifier.

Resistivity

The term resistivity measures the resistance or hindrance caused by the ions of water while conducting electricity. This factor is typically high in type I and Type II pure water types. It is said that the more resistivity, the less is the ionic content and hence, makes the pure water more desirable for lab work. The water purification system for laboratory use also uses ohm-cm; this feature produces type I and type II water.

TOC – Total Organic Content

This term is designated for the total organic content present in the water. While carbon testing, the TOC is measured. The measured value provides accurate measurement for the purity of water. This measurement also accounts for the presence of microorganisms with organic content in any laboratory water purifier.

Turbidity

Turbidity is defined as water clarity. In some of the water purification systems for laboratory use, have the turbidity index. This turbidity level gives a rough idea about the water purity along with the contaminants and other materials present in it. The turbidity check is advised for the low pure water like type III and Type IV.

Hence, the above four factors determine the purity of lab water or pure water. It is advisable to check the purity first and then commence any experiment. This way, the accuracy of the experiment does not get affected and perfect results are obtained through the use of a laboratory water purifier.

What are the contaminants?

Contaminant is any substances you do not want in your water. These are also called impurities. Some common contaminants found in water are particulates, dissolved inorganic (solids and gases), dissolved organics, microorganisms, DNA, RNASE and pyrogens.

What purification technologies are currently available to meet water purity requirements?

Pre-filtration removes particulates and may include activated carbon to neutralize agents like chlorine and chloramines. The main treatment process is usually a reverse osmosis membrane, which removes up to 99 percent of water impurities. Other supporting technologies include specific modules and cartridges, ultraviolet lamps, and ultrafiltration to further ensure that the CLRW water quality is consistently and reliably met, while minimizing operating costs and the need for user intervention.

Pure water standards are complex and a good analytical environment is required to conduct any laboratory experiments. A laboratory water purification system is installed to produce pure water used to perform all laboratory experiments.