Working With Purified Water

Water is vital for all life existing on the earth. Laboratories which undergo various study, research, and applications require water in large quantities for various purposes. Water is used as a reagent, to prepare samples, buffer, standards, blanks, dilute, equipment cleaning, glassware rinsing, and more. Normal tap water or purified drinking water cannot be used for laboratory purposes. The water is purified specifically for laboratory applications through various methods. Water purification system for the laboratory provides different grades of lab purified water and is used depending on the application’s sensitivity.

It is crucial to learn the Do and Don't of using a water purification system for laboratory producing lab purified water. This helps to avoid common mistakes of handling lab water purification systems and lab purified water. This will enhance the performance of sensitive analytical applications.

The DO’s Of Handling Purified Water In Water Purification System Laboratory 

  • Flush the system before collecting water

Lab purified water produced by the water purification system for the laboratory is highly reactive when exposed to air. It tends to absorb other substances in the air. If the water purification system laboratory is not used for some days, then the volatile molecules that are present in the laboratory environment will contaminate the water at the system’s point of use. So, it is best practice to flush some amount of water before collecting water for laboratory use. This helps to get high-quality purified water for sensitive laboratory applications for better performance.

  • Monitor your water’s quality

It is important to monitor the water’s quality to measure its purity. Many lab water purification systems display a “Resistivity” value which describes the ionic quality of water. Some lab water purification systems also describe the TOC value which describes water purity from organic contaminants. Resistivity and TOC is the common measure to determine the purity of the water. The lab water purification system which produces ultrapure water will have a resistivity of 18.2 and TOC values below 5 ppb. If the resistivity of the system falls below 18.2 then there is an issue in the purity of water in the laboratory water purifier and it is to be resolved.

  • Pay close attention to the final filter of your water purification system

Modern laboratory water purifiers deliver different grades of water in the single water purification system. If any final filters are used in the laboratory water purifier for specific purposes such as sensitive analytical applications. Before collecting water from the lab water purifier ensure that the filter is placed at the point of use for such applications. Modern lab water purifiers now come with multiple dispensing units each having a different final filter from the single water purification system.

  • Select the appropriate container for your sensitive applications

It is vital to choose appropriate containers for your sensitive applications. The ultrapure water system for the laboratory delivers ultrapure water that needs to be taken in a container when it is used for preparing eluents or standards or reagents. The container is to be chosen carefully such that organic molecules or ions of the container material container that reacts with ultrapure water do not affect the performance of the laboratory applications. In the case of organic analysis such as HPLC (High-Performance Liquid Chromatography) borosilicate bottles are used, as this bottle does not release any organic molecules into the water. In the case of ionic analyses, polyethylene or polypropylene containers are used as they release fewer ions compared to glass containers. In applications such as ICP-MS containers made of fluoropolymers are recommended. It is important to cap the container immediately after collecting ultrapure water into the container to limit the direct contact of ultrapure water with the laboratory air.

  • Clean containers properly

The containers that are used to collect ultrapure water should be very clean to avoid further contamination of water. It is vital to clean the containers properly with high-quality water depending on the laboratory analysis or applications. In all cases, especially in critical applications, it is essential to clean the containers with ultrapure water several times. Avoid detergents and do not mix glassware that is used for other work in the lab. Have specific glassware for specific purposes in that particular laboratory application. It is also important to clean the lid or cap of the containers with the same care.

Trace analysis or ultra-trace analyses are very sensitive analyses that need to be done with more care. Even laboratory items that are present in the lab environment such as gloves, marker pens, paraffin film, or floor cleaning products may release contaminants that affect the quality of the water. It recommended minimizing these products where sensitive analysis is performed. This will in turn minimize the contaminants in the air and hence maintain the quality of water.

  • Choose your system’s location wisely

Sensitive laboratory analysis like trace analysis is to be performed in a place where there are less or no chemical products or contaminants of ultrapure water present in that environment. Make sure that the ultrapure water system for the laboratory is placed in a clean environment i.e., away from where chemicals are used, windows, and air conditioning vents.

On the other hand, it is always preferred to place the ultrapure water system for the laboratory near the laboratory’s washing area or where the common reagents are prepared. The modern water purification system provides you with the flexibility to place water dispensers in different locations according to your need.

The DON’Ts Of Handling Purified Water In Water Purification System Laboratory 

  • Do not delay changing your water purification system’s cartridges

The water purification system for the laboratory uses different cartridges (such as ion exchange resin, RO membrane, and more) for purifying the water. It is important to ensure that the cartridges are not used beyond the manufacturer's recommendations even though it delivers enhanced quality water. 

Ion exchange resins that are used in the cartridges suddenly or unpredictably get exhausted and release more impurities. Unfortunately, If this unpredictable exhaustion occurs on the day of the crucial experiment, it will affect the results of the experiments. It is vital to change the cartridges as recommended by the lab water purifier manufacturer. This will help to avoid such critical situations and deliver high-quality water consistently.

  • Do not store ultrapure water

The ultrapure water is highly reactive when exposed to the air. This ultrapure water quickly absorbs carbon dioxide from the air and results in carbonic acid, carbonate, or bicarbonate that changes the pH value of water. When the ultrapure water is stored in a container then the container itself contaminates the water with the ions or organics the container is made up of. Bacteria and algae are developed if the water is stored for a long time near the window directly to the sun. Microorganisms like bacteria release by-products such as endotoxins and other organics. These contaminants reduce the quality of ultrapure and impact the results and hence do not store ultrapure water. So, whenever needed it is better to dispense freshly from the lab water purifier.

  • Avoid using plastic tub at the outlet of the water purification system 

It is a usual practice to keep plastic tubs at the outlet of the water purification system but this will lead to several issues. Plasticizers may leach inside the dispenser of the water purification system. Bacteria or algae may develop in the droplets that remain in the plastic tub. This will contaminate the ultrapure water that is collected for later use as well.  The modern water purification system comes with an easily adjustable point-of-use delivery device that fits the glassware. This helps to avoid splashes of water and the need for plastic tubs at the outlets.

  • Do not generate bubbles when dispensing water

Generating bubbles when collecting ultrapure water increases the risk of airborne contaminants in the water. These contaminants include volatile organics or inorganics which impacts laboratory analysis. To obtain optimal dispense of ultrapure water, tilt the container sideways so that the water slides on the wall of the container. This reduces the bubbles and risk of airborne contaminants in ultrapure water.


It is vital to choose a suitable water purification system for your laboratory. The same care is to be taken while handling the lab water purifier and the purified water. The do’s and don'ts we discussed provides you with a better understanding of handling the water purification system for laboratory and lab purified water. This will allow you to obtain high-quality water and get better results for sensitive analytical techniques.

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