9 posts / 0 new
Last post
RedBull's picture

Hello, everybody,

I am a rookie in the laboratory.

Here, I have a question about milli-Q water.

I had often heard other people talking about using milli-Q to prepare solutions.

Now, what is milli-Q water?

Hope some can answer me.

Thanks very much.....

SanDiablo's picture
Milli-Q water refers to

Milli-Q water refers to ultrapure laboratory grade water that has been filtered and purified by reverse osmosis. Millipore manufactures the gold standard for such systems in the laboratory, thus has risen to the top of brand recognition (like Kleenex for tissue and Band-Aid for adhesive bandages).

When a protocol calls for Milli-Q, it is meant to distinguish the water from tap water (dirty and full of salts, minerals, and possibly bacteria) and from dI (de-ionized) water, which is cleaner than tap water, but still may have some undesirable components. In the lab, dI water may be found in a special (hopefully labeled) tap near the sink and usually has a white handle.

MilliQ water will be found in a central location dispensing from some sort of cartridge-based filtration system and may require "tuning" before it is ready for use. See more details and some pictures. Ask someone in your lab to show you how to use it.

If you do not have such a system, your lab may be buying fancy ultrapure bottled water, so use this instead. Bottom line is when a protocol asks for Milli-Q, use the BEST water you can find.

atcg's picture
It is certainly worth a few

It is certainly worth a few extra cents to buy the Milli-Q water, than settle for some other brand of ultra-pure H2O!!! There is a REASON that protocols specifically call for Millipore brand - it is simply the best!

bwbrian's picture
I? MilliQ really any

I? MilliQ really any different than water purified by the same method, but using equipment from another company? I doubt it. Most people refer to MilliQ water because it is the most common water purification system . . . just like they ask for a Kleenex when they sneeze.

santoshk.sbt's picture
hello everybody,

hello everybody,
I am a research student in an institute recently I got a confusion which is, how MiliQ water differs from Elix water and what is the basis for the selection of either of them for my experiments

Merck India PR
Merck India PR's picture
Milli-Q vs. Elix Water

Hello, I think I can help you under stand the difference between Milli-Q Water & Elix Water.Milli-Q Water is the name of Merck Millipore's Ultrapure Water i.e. the Type-I Water, the purest form of water with no contaminants or elements whatsoever. It is purified to the highest quality, even eliminating any gas in it. Whereas Elix Water is the name of Merck Millipore's Type-II Water which is also known as Pure Water. It is a pure form of water that has eliminated any dissolved impurities.Ultrapure Water or Milli-Q water is best suitable for applications used in laboratory research and analysis that needs purest quality water for 100% accurate readings. Whereas Elix Water or Pure Water is mostly used as a feed for Ultrapure Water Systems and in non-sesitive laboratory application across industries. 

Sami Tuomivaara
Sami Tuomivaara's picture


Don't be fooled overenthusiastic proponents of some particular brand of lab water purifiers... MilliPore, Barnstead and probably other manufacturers make purifiers that give you Type 1 laboratory water (most important parameters are resistivity 18.2 Mohm cm-1 and ppb levels of total organic carbon) using a combination of techniques: charcoal adsorption, filtration, ion exchange, uv radiation... Usually the water also is pretreated with continuous distillation or reverse osmosis with a separate unit before feeding it into the ultrapurifier.

Anyway, this water is purer than a lot of biochem (and related fields) experiments actually require, but this have become a standard of sort and good so! Using this type of purifier lessens inevitable variability that comes with using tap water and also gives a de facto standard for everyone doing wet science...

EDIT: For santoshk.sbt Looks like Elix gives you Type 2 lab water... a bit less pure (resistivity 1 Mohm cm-1, thus more ions present). Here are MilliPore's _suggestions_ for which type purifier to use with various applications...

Good luck and Cheers,

Merck India PR
Merck India PR's picture
MilliQ water is ultra pure water

Technically, UPW or Ultra-Pure Water OR MilliQ Water is called for water that is Biologically and chemically almost H2O without any contaminants with clear specifications. Also, It is much more technically apt for the water requirements where you need water with clear biological, elemental, Organic level specifications.

Martha Sturgis
Martha Sturgis's picture
Milli-Q - Ultrapure Water

Milli-Q is the brand name for Merck Millipore's Ultrapure water. As a market leader in the lab water industry, ultrapure water is often referred to as Milli-Q Water. In basic, Ultrapure water is the water with highest acceptable quality i.e. extracted of all the impurities, dissolved solvents or minerals. Ultrapure water, also called as reagent grade water is required in Analytical and Biological applications.