Sciencemadness Discussion Board

how to make double distilled water

ScopeGuy2 - 28-12-2015 at 22:51

I need about 60ml of double distilled water. I need it to add to two 30ml bottles and some stain that I am getting ready to mix. I thought I would just get a bottle of distilled water from the store and distill it again. I am looking for a way to do it on the cheap since I don't have a lab set up yet. and just getting a few items over the last couple months. Would this work? http://www.wikihow.com/Make-Distilled-Water
or is there a better way?

Thank you

j_sum1 - 28-12-2015 at 23:09

Why do you need high purity? Exactly what putity do yo need?

For my purposes I simply use bottled distilled water from the supermarket or hardware store.

The method shown is certainly a valid method for distilling. The limiting factor is likely to be the cleanness of your equipment and handlling practices.

Zephyr - 28-12-2015 at 23:09

Double distilled basically just means they want very pure water, for what you need it for I am fairly certain the specific distillation count is irrelevant, as long as it is very pure.
Something like this should work fine: http://www.amazon.com/Distilled-Water-Laboratory-Reagent-Lit...

Tdep - 28-12-2015 at 23:25

Interestingly no distilled water I can buy at the supermarket is actually purified through distillation. Its all done through ion exchange membrane technology stuff, its cheaper and more efficient

Volanschemia - 28-12-2015 at 23:32

Obviously the best way to distill water would be with a proper distillation rig that has been thoroughly cleaned beforehand, but the way with the pot and bowl would work well enough.

As j_sum1 says, make sure the bowl and any other equipment that will come into contact with the water is clean.

@Tdep, Yeah, I've noticed that too. I tried to get some once and it and on evaporation had solid impurities in it. Distillation is really the only way to remove everything (to an extent).

[Edited on 29-12-2015 by Volanschemia]

Zephyr - 28-12-2015 at 23:33

That's odd, does anyone have any idea how pure it actually is?

Tdep - 28-12-2015 at 23:50

You can get it purer than distilled water with membranes i'm pretty sure. At least it's easier with an industrial setup, because ions cling to glass and all that sort of nonsense. I know my uni produces a distilled water thats a reasonable quality with membranes but they also produce a seperate Milli-Q water which requires even more effort, and more run through more equipment.

So i'm sure the supermarket does not sell Milli-Q water, its not that level of pure, but it seems to be pretty good.

Dr.Bob - 29-12-2015 at 07:20

Many businesses, colleges, and medical facilities have a clean water system, ask your friends and family if they have access to a pure water system and then you can see if that is good enough for your needs. If your distillation system is not very clean to start with, then any distillation will not help as much, so buying or finding clean water may be easier. Most biological stains would work fine in any clean water. Tap water is bad, as it contains, chlorine, fluorides, sometimes chloramines, minerals, salts, and often other stuff. But any "pure" water than is sold as such should be fairly good, I just would just buy one labelled with how it is purified, not just "bottled water".

ScopeGuy2 - 29-12-2015 at 22:43

Thank you everyone for all the help.

Tsjerk - 30-12-2015 at 06:38

Usually the stuff sold in the supermarket is demineralized water (abbreviated as dH2O), so the confusion with distilled water is easily made.

If you only need 60 ml, I suggest asking at a university for Milli-Q. It is pure water run over a column, in order to purify it further. I use about a liter per week, but never have to write down how much I use, although the column is payed by a different department than mine. I don't think the would mind giving you 60 ml.

Irish9 - 10-1-2016 at 20:36

Not sure if it would be available in your area but I use 'industrial steam distilled water', it is branded Westlab and I buy it off them for Au$30 per 20l. This stuff is labeled less than one part per million dissolved solids, should be good enough for almost any application.

Texium - 10-1-2016 at 21:42

Quote: Originally posted by Tsjerk  
Usually the stuff sold in the supermarket is demineralized water (abbreviated as dH2O), so the confusion with distilled water is easily made.
No confusion here. The stuff I buy is clearly labeled "DISTILLED WATER"