YT2095
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Beware "Deionised" water
the stuff you buy at car shops for topping up car batts.
Some of it contains Chlorine!
I nearly lost 3 days work purifying silver metal for silver Nitrate as a result of this.
I am NOT happy!
\"In a world full of wonders mankind has managed to invent boredom\" - Death
Twinkies don\'t have a shelf life. They have a half-life! -Caine (a friend of mine)
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Antwain
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You should send ugly words to the manufacturer. As far as I know, chloride is a battery killer too 
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UnintentionalChaos
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Even white distilled vinegar has a fair amount of chloride in it (learned that when making lead acetate). I just buy distilled water by the
gallon..around 70 cents US each and no chloride contamination.
Department of Redundancy Department - Now with paperwork!
'In organic synthesis, we call decomposition products "crap", however this is not a IUPAC approved nomenclature.' -Nicodem
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JohnWW
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Would rain-water do for the purpose? I find that it seems to be OK for topping up lead-acid batteries, although it is known to contain dissolved CO2.
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chemkid
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Rain water is often acid (acid deposition), however this would be OK for lead-acid batteries, it would not work for most experiments. Furthermore,
there is usually a good bit of suspended solids in rain water as well.
Chemkid
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bio2
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I once tested some distilled water intended for batteries
and it was 80PPM TDS. Only one state in USA (California)
has standards for distilled water and it is <10PPM which is
still not very good for some purposes.
For my use in making ionic/collodial silver I had to buy RA
grade double distilled water which sometimes still tested at
almost 1PPM.
Buyer beware when purchasing distilled water because the TDS is determined by how often the maker cleans their stills. In my experience some brands
are more reliable than others.
Good quality de-ionized water is lower in TDS than distilled.
Now I run regular grade RO water through de-ionizing resin and get better results than with the RA double distilled water.
[Edited on by bio2]
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chemrox
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I've been very fortunate in having spent most of my life in two places that both had(ve) extraordinary water quality; one of them had water with an
average TDS around 6 mg/L (PPM is an air parameter- vol/vol). The other is about the same, ranging from 4-10 mg/L. I'm not surprised to find the
DI water of commerce is sometimes a rip. The "purified water" or "spring water" is usually tap from someplace that one of the big soft drink
companies has a contract with. It's a worldwide scandal; the appropriation of water by Cocal Cola and Pepsi for the purpose of selling bottled water.
Municipal water supplies all over Latin America have been sold to these pirates and then sold to you as "Mountain Spring Water." There are regs
being promulgated as we 'speak.' However, technically the water can be 'deionized' and still contain chlorine. I don't think there's any kind of
standard for DI. Amazingly, my office mate and landlord bought a cheap, mount it on the faucet, water purifier that completely rids the water of
chlorine. Even after years of service. The health food store has a machine that runs reverse osmosis on city water and the city water here is never
over 10 mg/L TDS and rarely is that high. So chlorine and flouride are the two concerns. So, this was really long winded to get to my
recommendation: buy water from a vendor that uses RO or get a purifier and check it with a swimming pool kit from time to time. Or, as has been
said, get the distilled water, its usually OK. Can't have hypochlorite clogging up steam irons or the consumers *will* bitch.
[Edited on 25-10-2007 by chemrox]
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evil_lurker
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I have a 5 stage Barracuda RO unit with DI from http://aquariumwaterfilters.com/
Thing works great, it uses quality components, and its relatively cheap to @$230USD.
Includes inline TDS meter, pressure gauge, and storage tank.
Not all chemicals are bad. Without chemicals such as hydrogen and oxygen, for example, there would be no way to make water, a vital ingredient in
beer.
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Antwain
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I could always pinch the "milli-Q" water from uni, but that stuff is not cheap and I reckon they wouldn't be happy if several liters disappeared. I
usually use "deionised water" from the supermarket. It is only ~$1/L and isnt too bad for most things, but I don't know its actual assay.
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Aqua_Fortis_100%
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I get my 'distilled' water on the upper part of the fridge, as a crust of ice (upper part of the freezer because that is the only part which generally
not touch the contents of the frezeer (foods, meat , etc)..and then I let it melt and store it. Is good at least for me..And maybe to most amateur
that have an old non auto-de freezing refrigerator. The only drawback is that you have to wait a lot to get some amount.
the good thing is that is just free and easy to get 
[Edited on 26-10-2007 by Aqua_Fortis_100%]
"The secret of freedom lies in educating people, whereas the secret of tyranny is in keeping them ignorant."
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prole
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The distilled water you buy in the store isn't pure or clean.
https://sciencemadness.org/talk/viewthread.php?tid=5506&...
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YT2095
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well I wasn`t after ULTRA PURE, but something with less chlorine than Tap water would have been Nice!
I don`t give a crap about Phthalates and the likes, but the Cl2 is DAMNED annoying!
\"In a world full of wonders mankind has managed to invent boredom\" - Death
Twinkies don\'t have a shelf life. They have a half-life! -Caine (a friend of mine)
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Klute
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Off topic, I know, but ppm can also be used for concentrations: this is the unit we use for atomic and molecular emission spectrometry, and other
analysis technics using highly diluted solutions.
It's even used in NMR (Hertz). So I guess the "parts per million" can be applied to anything that can be considered as a "part". Even humans for
statistics, no? (that's e bit unlikely, I admit  )
Sorry for the intrusion
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12AX7
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1 ml == 1g H2O at 4C or so. Therefore, 1mg/L H2O = 1mg/1kg = 1m/1k = ppm.
In NMR, ppm refers to a shift in the resonant frequency of a precessing proton in a magnetic field. At some magnetic field strength, you might have
50.000 000 MHz on your TMS signal, and 50.000 050 MHz on a methyl's hydrogens, for a shift of 1 ppm. Molecular interaction happens to be expressed as
a rather small ratio of the precession frequency, so ppm is constant whatever magnetic field you're testing at.
Tim
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Klute
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Yes, this is what enables spectras from different devices to be compared, as the NMR machines often have different ranges. I've always found it
strange that proton couplings are still expressed in hertz, however. In that case I suppose the exact coupling value changes from device to device for
a same proton.
Totally drifting out of topic though. I will refrend.
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Traveller
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I live in an area with high humidity. I have a small de-humidifier I keep going most of the time to keep the humidity in my house down to a tolerable
level. It easily produces two litres of water daily that must be dumped.
Is this water equivalent to distilled water?
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bahamuth
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To get some good clean analytical water one might ask the local university or a local lab or the similar if one could buy or get some liters for free.
RO water from a Millipore setup, which all labs have, is dirt cheap and good enough for most purposes.
18 Mohm water (MilliQ) water is also relative cheap by the liter, it is just the setup/instrument that costs a leg and an arm. I'd guess like $1 per
L.
Lucky me, I get all my water from the lab, just fill RO water on 2.5 L carboys and put it in my backpack once a week or so
MilliQ water is a little more restricted but only because it takes several hours to fill up the tank which is 3 L or so..
Or even better, just make your own still, triple distill it and it is as good as most. And if you plan on storing it, filter it through a 0.2
micrometer filter to get rid of all the bacteria as to avoid growth.
As a side note, Ion Exchanged water is often called DI, or RO water, which in many cases means that just the alkaline earth ions are exhanged with
sodium and potassium, also leaving the anions in there.
Any sufficiently advanced technology is indistinguishable from magic.
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hissingnoise
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Not really, it will contain dust specks, CO<sub>2</sub> and anything else in the air that's soluble!
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triplepoint
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Quote: Originally posted by Traveller  | I live in an area with high humidity. I have a small de-humidifier I keep going most of the time to keep the humidity in my house down to a tolerable
level. It easily produces two litres of water daily that must be dumped.
Is this water equivalent to distilled water? |
Dehumidifiers often develop a significant moldand bacteria buildup. Depending upon your intended use, that could present a problem.
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unionised
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Depending on what the local tap water is like, the water from a dehumidifier might be a good material to feed to a still.
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