[Colinitrogen]

Hey All,

Quick question. I purchased distilled water online. It came with a label rated at 9ppm. I've not opened it, but this seems quite high for distilled water. Previous water which I've bought and tested from another retailer came in at 2ppm and my own distilled water at 0ppm.

I was wondering if anyone could provide me with the standard classifications from US, EUR and BP guidelines on PPM for distilled water as I don't want to break the seal on something that I cannot use.

Kind Regards

[Arkcon]

Hey All,

Quick question. I purchased distilled water online. It came with a label rated at 9ppm.  I've not opened it, but this seems quite high for distilled water. Previous water which I've bought and tested from another retailer came in at 2ppm and my own distilled water at 0ppm.

Hi there.  The unit you use, ppm, means what, exactly?  You're either using jargon, or you're leaving something out.

I was wondering if anyone could provide me with the standard classifications from US, EUR and BP guidelines on PPM for distilled water as I don't want to break the seal on something that I cannot use.

Those are in the relevant pharmacopeia, which are expensive, and copyrighted, but if you're manufacturing pharmaceuticals to the standard required by the governing body, you are required to have a copy on hand.  For general interest, the info is Goggleable, but the specification is lengthy, obtuse, and ... in no way uses your random units -- ppm.  So you still have more explaining to do before we can help you.

Kind Regards

[Colinitrogen]

Hi,

Sorry I dont know much about it, not trying to be vague but yes I guess it's jargon.

I've been told the water distiller retailer uses ASTM D1193 and typically achieve Type IV (or Type III on occasion). However I can't access this as it's paid for information.

[Arkcon]

Oh good, I can understand your specification now.  Here's a link to the definition of Type II,III,IV water:

https://www.astm.org/DATABASE.CART/HISTORICAL/D1193-99E1.htm

ppm isn't mentioned on that page, nor is it part of the (various and convoluted) pharmacopeia specifications.

What do you need, and for what application?  Ppm of what, sodium, chloride or silica?  Define 'ppm' and tell us how you can use it to describe the quality of water.

[Colinitrogen]

Ignore the PPM thing. I was just wondering if there was a set PPM limit classification for something to be called distilled water but from what I've found threes ppm for each of the elements you've mentioned and also in some other purified water applications also stuff like endotoxin limits.

It's for my autoclave, enigma 12, but I also have my own water distiller that was imported and just wanted to compare using a TDS PPM meter, which I achieve 0ppm and other distilled water's purchased from Ebay have 2ppm. I've got a Hannah water analysis machine on the way so I'll be able to get the EC/PH soon enough.

[Arkcon]

Hrm.  I think I'm understanding your situation more and more with each post.  OK.  You have an analytical instrument that call itself a "distilled water checker"TM, and its calibrated in ppm.  Maybe you check its calibration with a dilute sodium chloride solution at some very low ppm.  But the pharmacopeia's use uS as a measure of how much conductivity there is.  Ppm is a cute unit, but from an analytical standpoint, ppm of what?

Your autoclave should specify what level of water it needs.  But your ppm meter isn't going to tell you what you have.

[wildfyr]

Isn't ppm basically uL/L? Which is an annoying unit, but does mean something. Obviously molarity is what actually matters, and without knowing the ID of the ion I don't know how your machine knows how to give ppm. Anyhow, I agree 9ppm total conductive impurities does seem a little high. It's the sort of thing that could come from unclean glassware though.

[Borek]

TDS assumes linear dependence between ppm and conductivity. This assumption works reasonably good for natural waters, with (in a way) similar composition of the ions present.

It doesn't tell anything about what is really dissolved, not does it work with distilled lab water, which can be contaminated with things far from those typically present in the natural water.