Different grades of water used for different applications

Water is commonly used as a laboratory reagent. Water used in the laboratory produces a potential impact on the experimental results. It is important to understand the basic principles of laboratory water that help scientists use the right water grade for laboratory applications. The modern water purification system for the laboratory with the best quality monitoring system helps research scientists to ensure the quality of the water at the point of use.

Define The Quality Of Water Required

Generally, the tap water we get is purified by the local water corporation as such it is used for drinking. Tap water still contains many substances such as particles, ionic compounds, organic molecules, microorganisms, and dissolved gases. Water purification system for laboratory use removes these contaminants such that it does not interfere with the laboratory applications. 

In the case of liquid chromatography, for a good quality baseline, the water used in the mobile phase should be free from organic molecules. In the case of glassware rinsing, autoclaving, or microbiology organic molecules have less impact. This encounters the importance of identifying the specific quality of water that is required for that particular application.

When the new laboratory is started for specific applications, the contaminants that affect the experimental results or researches are identified. Then the lab water purification system that produces a specified grade of water is to be chosen such that the requirements of the laboratory applications are met.

Organizations such as ASTM, ISO, and CLSI define the water quality standards. The value of different grades of water from the organizations differs slightly. The laboratory-grade water is commonly classified as Type 1, Type 2, and Type 3.

  • Type 1 - It is also referred to as ultrapure water. This water contains high resistivity of 18.2 MΩ-cm with a low level of ion, organic molecules, bacteria, and particles. This type of ultrapure water is obtained by the combination of various technologies such as Reverse Osmosis, activated carbon, ion-exchange resins, ultraviolet photooxidation, ultrafiltration, and electrodeionization. It is used for highly sensitive applications such as HPLC, gas chromatography, and Inductively-Coupled Plasma Mass Spectrometry (ICP-MS).
  • Type 2 - This type of water is referred to as laboratory-grade water. This type of water contains a resistivity of 5 MΩ.cm and TOC < 50 ppb. This Laboratory grade water is produced using technologies such as RO, activated carbon, Electrodeionization. This type of water contains fewer ions and bacteria. It is commonly used to prepare reagents and buffers.
  • Type 3 - This water is generated by Reverse Osmosis or ion-exchange resins. It is used for non-critical applications such as qualitative analyses, glassware rinsing, and water baths.

Read more: Laboratory Water Purification Systems

How To Define Your Water Purification System laboratory

It is important to define the required water purification system for the laboratory. It depends on several factors such as feedwater quality, required quality of purified water in the laboratory applications, the required capacity of purified water, contaminants that are to be removed effectively for your laboratory analysis, technologies used in the lab water purification system, depends on your budget, and more are to considered to get the right laboratory water purifier.

Read more: Buying Tips - Water Purification Systems For Laboratory

Importance Of Water Pretreatment

It is important to pretreat the water, before feeding it into the water purification system laboratory. This will help you to get high-quality water. This pretreatment also ensures by protecting the water purification system laboratory from further expensive damages. The resins and the filters have to be replaced as per the recommendations of the manufacturer. Exhausted resins release large contaminants like particles, organic molecules, and bacterial growth into the water. Further purification with a polishing system also will not generate high-quality purified water. 

Pretreatment is the primary step in the water purification process. Water pretreatment systems involve a combination of purification technologies like Reverse Osmosis,  activated carbon, EDI (Electro Deionization), and more. This pretreatment water in the laboratory water purifier enhances the long life of the lab water purification system and also produces consistent reliable high-quality water.

Storing Purified Water

High-quality lab purified water is highly reactive to the surroundings. The lab purified water absorbs chemicals even from the storage container. Even when the ultrapure water is stored in the high purity storage containers it will degrade the quality of the water. The purification process is required if it is stored for some hours. And so it is highly recommended to use it at the point of use without storing.

Monitor Water Quality

It is vital to monitor the quality of the water whenever you need the water from the lab water purification system. The best water purification system for the laboratory uses monitoring tools. Resistivity meter to measure the resistivity (reciprocal of conductivity) of water that defines the ionic impurity of the water or level of ions present in the water. TOC (Total Organic Carbon) meters define the organic impurities in the lab purified water. Generally, TOC is measured by the UV photo-oxidation of organic matter and converting it into carbon dioxide. These tools ensure the quality of the water used for your laboratory applications.

Bacterial Removal

It is challenging to remove the bacteria from the water purification system for laboratory use. Bacteria in the lab water purifier will enter if any openings are there in the lab water purifier. These bacteria will grow rapidly throughout the lab water purifier. These bacteria will develop a biofilm layer, this biofilm will protect them from the periodical treatment of biocides.

Bacteria that release small organic molecules and inorganic ions will affect many applications like ion chromatography, HPLC. These bacterial impurities will appear as large peaks in the chromatography applications. Bacteria also release enzymes and endotoxins.

Nucleases of the bacteria will affect molecular biology experiments in large with the use of nucleic acids such as RNA and DNA. Endotoxins released by the bacteria will affect the cell function and the growth of mammalian cell cultures. 

It is important to monitor the bacteria at each stage of the water purification system laboratory. These bacteria are to be removed with a UV photooxidation process followed by ultrafiltration. Bacterial growth can be minimized by regular maintenance and changing cartridges regularly.

Choose the Right Grade Of Water For Specific Applications

It does not mean that the ultrapure water system for the laboratory can be used for all the laboratory use.  Sometimes the ultrapure water system for the laboratory is unnecessary and expensive. Ultrapure water easily reacts with other chemicals and dissolves gases in the atmosphere. It absorbs carbon dioxide easily when exposed to air and forms weakly carbonic acid. This reduces the pH value of the ultrapure water from 7 to 5.6. In some specific biological applications, the trace of elements in the water will be beneficial.

The ultrapure water system for the laboratory is preferred only for critical applications. Because of the aggressive nature of ultrapure water to react with other chemicals, Type 2 and Type 3 water is preferred for other applications where prolonged contact of the material is required, rinsing glassware, and more. It is more important to use the right grade of water for the right purposes.

Read more: Applications Of Lab Water Purification


Water is primary for most laboratory applications. Some of the primary things that have to be considered while using the laboratory water. It is important to understand the different types of water and their applications. Choose the right laboratory water purifier for your laboratory that uses a combination of different technologies and provides you high-quality water with effective removal of contaminations. Monitor the quality of water every time when you use it for consistent and reliable water quality. Lab Q water products provide different grades of water with easy installation, maintenance, and a good water quality monitoring facility. Contact Lab Q water to choose the best water purification system for your laboratory.

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