Let's talk about lab water
Foolproof lab water filtration
17 Apr 2015
Water may be a fundamental component of every experiment, but it can also be the source of many problems in the lab if it becomes contaminated. This can lead to a seemingly endless list of troubleshooting nightmares.
Whether you’re running a PCR and need to safeguard your reaction against those pesky nucleases or you want to ensure your gel doesn’t go running awry because some inorganic ions upset the charge in the tank, you need to make sure you have a fail-safe means of getting the water purity your precious experiments deserve.
To help, today’s blog looks at the benefits of dual ion exchange (IX) filters for improving water quality.
Messy measurements
Water purity is measured using resistivity (MΩ-cm) and the pure water standard is set at 18.2 MΩ-cm. However, even the best resistivity monitors aren’t completely accurate and can be out by 0.2 MΩ-cm. This might not seem like much in terms of resistivity, but it could distort the concentration of impurities by more than two-fold. Impurities which break through the filter can’t be detected by the resistivity monitor and so often go unnoticed. This could compromise your experiments.
Resin relays
One way of purifying water is to use an IX resin. This exchanges positively charged hydrogen ions and negative hydroxyl groups for water impurities such as inorganics (which carry a charge). Strongly charged contaminants such as calcium ions often bind first and fill up the resin, meaning weakly ionized impurities in the form of organics, silicon and boron can slip through. While these resins have provided protection against water contaminants to scientists the world over for years, they don’t last forever. Like all good things, these eventually come to an end and need to be replaced.
Polished purity
So how do you conquer failing filters and unnoticed impurities while still making use of IX resins? The answer is… get two! A dual cartridge system such as PureSure, offers a ‘belts and braces’ approach. This means that any troublesome contaminants that manage to sneak through the first barrier are swiftly passed on to a second line of defense in the form of another IX resin filter, where they are then detained, preventing them from causing havoc with your experiments (see below).
Even better is the fact that there are also two resistivity monitors; even when the first filter inevitably fills up, thereby removing your first line of filtration defense, there’s no need to call out the cavalry (a.k.a. ELGA tech support) just yet. This is because the second filter lets you carry on contamination free for another 1000L – which is still a lot of buffer and reaction mix dilutions, any way you look at it.
This approach is also economical, because when your shiny new cartridge arrives, you can use this to replace the second filter (which you then use to replace the first). This way you can increase the life of the cartridge by up to 80% and proceed without any interruptions to your work or water flow.
The powerful partnership of a dual filter system proves that less isn’t always more when it comes to purification. PureSure allows you to blissfully continue generating data to test your research hypothesis, without the pain of unnecessary interruptions.
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