MilliQ water vs bi-distilled water - (Aug/27/2012 )
Hy everyone
I have a problem in my lab - the miliQ water sistem is broken and never be repaired and all the protocols for tissue culture media ( and transformation media) that i am using require miliQ water.
Since the sistem is broken, the question that arise is: it is really neccesary to use miliQ water instead of duble-distilled water?
People in the lab just told me to find out the answer, so, they could not realy indicate me any solution.
Thank you ,
Oana
Hello Oana:
Try this website out for answers to your question:
http://www.protocol-online.org/biology-forums/posts/15937.html.
Someone else asked the same question on a different forum.
MQ-grade water can be deemed to be more "pure" in terms of dissolved ions than distilled water, where ions dissolved in the water before distillation can be carried forward into the end product, even after double-distillation.
MQ-grade water has become the industry standard, but distilled was the norm when I started my career. Just because your protocol calls for MQ water now doesn't mean you can't substitute in double-distilled. Make sure you sterilize the final products (TC media, transformation mix) before you use them.
Good luck!
Hy
Thank you for your re-play! The link that you inserted says that the page connot be found.
Anyway, I have concluded that i can replace the miliQ water with dd-water ( some colleagues in other groups use neither miliQ nor dd, just simple purified water with a comercial instrument) . Of course, all the media is autoclaved before use, so the problem of organic/living contamination is eliminated.
Regards,
Oana
Tissue culture medium can not be autoclaved before use as it denatures the heat sensitive components, such as L-glutamine, in the medium. TC media should be sterile 0.1 um filtered into clean TC bottles after preparation.
MilliQ is de-ionized water, whereas ddH2O is double distilled. In practice either could be used, but MilliQ is probably preferred as it tends to have fewer impurities than ddH2O.
bob1 on Mon Aug 27 22:28:19 2012 said:
Tissue culture medium can not be autoclaved before use as it denatures the heat sensitive components, such as L-glutamine, in the medium. TC media should be sterile 0.1 um filtered into clean TC bottles after preparation.
MilliQ is de-ionized water, whereas ddH2O is double distilled. In practice either could be used, but MilliQ is probably preferred as it tends to have fewer impurities than ddH2O.
There are indeed compounds such as phytohormons, vitamins, antibiotics which denaturate at high temperatures such as those in an autoclave, but ussualy, these compounds are added in the media after sterilization and allways in the flow.
Anyway, colleagues told me that just simple tap water is not recomended, but any kind of filtered/distilled and so on...can be used.