Water is ubiquitously used in labs for preparing standards, samples, reagents, media, for cleaning glassware and even as a medium in which reactions are carried out.
However, impurities present in water can impact the outcome of an experiment, so the use of contamination-free water is essential in all laboratories.
Download this guide to learn more about:
- The types of lab water
- Purification techniques
- Water quality measurements
How to Guide
How To Maintain Water Quality in
the Lab
Srividya Kailasam, PhD
Water, being the universal solvent, is ubiquitously used in labs for preparing standards, samples, reagents, media,
for cleaning glassware and even as a medium in which the reactions are carried out. However, impurities present
in the water can impact the outcome of an experiment. For instance, organic compounds can give rise to ghost
peaks in high-performance liquid chromatography (HPLC) experiments, or act as feed and support the growth
of microorganisms, impacting the results in microbiological and biological experiments. Suspended particles can
clog the narrow tubing and filters of instruments and sediment on their surfaces. Dissolved salts and gases can
not only corrode the equipment, but also impact the outcomes of the experiments. Hence, the use of water free of
contamination is essential in all types of laboratories.
Types of lab water
There are broadly four types of water available in a laboratory:
•
Type 1, or ultrapure water, which has resistivity of 18.2 mO and is free of DNase/RNase, is used for cell
culture, flow cytometry, immunology, genomics, proteomics, HPLC, ion chromatography, electrochemistry
and mass spectrometry applications.
•
Type 2 water is used in laboratories for purposes such as the preparation of buffers and media, or for
running spectrophotometric or electrochemical assays, as it is free of most contaminants including
chlorine, ions and organic matter.
•
Type 3, or primary grade water, is used as the feed for autoclaves, steam generators and ultrapure water
systems.
•
Feed water or raw water is obtained from natural sources and needs to be purified before further use.
While it is also possible to purchase water of a certain quality, such as “HPLC-grade” water, to prevent
contamination, this can be expensive and is not essential for all types of experiments. HPLC-grade or LC-MS
grade
waters contain very few impurities and are considered suitable for HPLC and LC-MS applications.1 Labs
.1
that do not own a system to prepare ultrapure water, or in cases where they suspect contamination of their
ultrapure water system, can purchase these for their work.
1
