Talk:Parts-per notation

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All of the information here is equally applicable to ppt, ppb, ppq etc and to some extent duplicates what is included in the concentration article. I therefore propose we move some of the content from the concentration page here and redirect to this from all uses of ppt etc. The articles are currently a bit of a mess with duplicate stubs, a redirect to the concentration and complete lack of consistency.

Just to summarise what pages I think should be redirected here:

This has been changed to a disambiguation page. PAR 15:44, 1 January 2006 (UTC)

--NHSavage 08:38, 14 August 2005 (UTC)

Yes, the mentioned pp- stubs should be redirected to a parts per notation page with a good explanation. Duplication of the relevant material in concentration rather than a move of that info would be in order. Vsmith 13:58, 14 August 2005 (UTC)
This article has been renamed after the result of a move request. Please now continue with the cleanup. violet/riga (t) 13:48, 21 August 2005 (UTC)
Cleanup done. I think that this article still needs some work to further explain the differences between part per by volume, mass etc. I will think some more about this and also link to this from the concentration article. --NHSavage 20:47, 26 August 2005 (UTC)

Contents

[edit] 2003-2004 discussion

"The ppm value is equivalent to the absolute fractional amount multiplied by one million." This needs to be expanded. For those who actually need this article, this will be more confusing than the words "parts per million."

An example would help (I mean, an example like "a drop of blood in a 50 gallon drum would be about n parts per million"). --Larry Sanger


Is the exact calculation/definition:

ppm = solute / solvent * 1000000 ?

or

ppm = solute / total solution * 1000000 ?

or could be both ? like we use percentage, sometimes it needs to specify which two we are comparing ?

also, is it must be the same units ? like mass over mass,

or it could be mass over volume, without specifying other variables like temperature ?

[edit] Examples

The examples don't seem to be too accurate. A drop is usually defined as 0.05 ml, which then gives;

1 drop in 50 ml = 1‰, 50ml is a very small cup
1 drop in 50 l = 1ppm 50 l is about 11 gallons, not 40
1 drop in 50 cubic metres = 1 ppb
1 drop in 50,000 cubic metres = 1ppt, a 50 m swimming pool is 50*25*2 = 2,500 m^3
1 drop in 50,000,000 cubic metres = 1ppq, 50,000,000 m^3 is equivalent to a lake covering a square kilometre, and 50 metres deep, which is more than "medium sized" IMHO --Tom k&e 11:23, 6 September 2005 (UTC)

  • I’ve addressed this in the re-write. Thanks. Greg L (my talk) 20:41, 4 December 2007 (UTC)

[edit] Other uses

PPM is also used to describe the accuracy of precision equipment such as a voltage calibrator. For example, see http://www.valhallascientific.com/calibrators/cal-2701c.shtml . 68.11.218.237 23:53, 19 April 2006 (UTC)

Thank you for this, I have added it in to the article.--NHSavage 06:50, 20 April 2006 (UTC)

[edit] absolutely confusing

Do you mean “parts per” notation, perhaps? Jclerman 15:35, 24 June 2006 (UTC)


[edit] Notes

The notes need to be totally redone. 3 does not refer to anything about it, and there is no 4. --Storkk 01:20, 20 August 2006 (UTC)

  • The notes section was disjointed and not the proper, Wikipedia way of doing things. After the re-write, its contents were either 1) redundant, 2) tangential, or 3) incorrect. Accordingly, the entire section has been deleted. Thanks. Greg L (my talk) 20:43, 4 December 2007 (UTC)

[edit] What the...

Well thsi article stinks. Its bloody confusing. If parts per hundred is the same as 100% stuff, then that means number of molecules per hundred total, not per every other 99. So 1pph is 1 molecule per 100 total molecules.

Just say that!Tourskin 03:41, 12 February 2007 (UTC)

I am concerned about the definitions as well. For example, it is not accurate to define "parts per hundred" as one particle for every 99 other particles. Instead, that might be a fair definition of "one part per hundred." But the definition is not helpful if the reader seeks to understand what "10 parts per hundred" means. Does that mean "10 particles for every 99 other particles"? Not at all; it means "10 particles for every 90 other particles." Nissynis 14:38, 8 June 2007 (UTC)

  • Agreed, the “1 part versus 99 parts remaining” was unnecessarily confusing. As now revised, the article is consistently 1 part per 100 (etc) parts examined. Thanks. Greg L (my talk) 20:44, 4 December 2007 (UTC)

[edit] WRONG, VERY VERY WRONG MY FRIENDS!

This article is complete crap - sorry for the terminology, but if my old chemistyr teacher was here to see this awful article... Parts per million is NOT involving particles. It involves mass. So for NaCl which could be 5ppm in water, thats 5 gramms of NaCl per 1,000,000 gramms of water. Tourskin 06:27, 14 February 2007 (UTC)

I don't see why you're so upset. Parts per million could just as easily be used to denote the number of particles as well as the number of grams. That's why its Parts per million and not any single unit.67.150.213.150 07:17, 4 March 2007 (UTC)

  • I agree Tourskin, the article was sorely wanting and was becoming a poster boy for Wikipedia’s shortcomings; the product of too many “drive-by shootings” by too many authors, and too little attention by someone willing to pull it all together into a coherent article. I've now revised it to address your concerns. Here’s what the article looked like before. I think simply having a link at the bottom of the article to Mole fraction is sufficient to address the concept of moles-per-mole mixing. Greg L (my talk) 22:02, 4 December 2007 (UTC)

[edit] Mentioning very few parts-per notations

Should we include examples for "very few parts-per notations" like homeopathy or large scale relations as in Orders of magnitude (numbers) or the Avogadro constant?

Homeopathy goes up to dilutions of one part per 1060 and even 10150, which are beyond Planck Scales in relation to the visible universe and therefore only imaginary. Ollj 23:08, 12 March 2007 (UTC)

  • I agree with Ollj. That topic best belongs in Homeopathy. The common parts-per notations ppm, ppb, and ppt are well recognized throughout science. Application-specific parts-per notations like ppg (parts per googol) ;-) …are best left to articles pertinent to that particular application. Greg L (my talk) 20:48, 4 December 2007 (UTC)

[edit] Parts per notation, found in Amaerican USP?

1:10 means that 1 part by volume of a liquid is to be diluted, or 1 part by weight of a solid is to be dissolved, by sufficient of the diluent or solvent to make the volume of the finished solution 10 parts by volume.


Does any one know haw this can be explained or show a worked example of the liquid at 5mls and 15mls and solid say at 1g and 10g. Thanks B

  • One could, but the treatment belongs in Algebra, not in this article. If you want a 1:10 dilution to end up with a finish amount of 10 units, you need to add 10/11 part to 100/11 parts in order to end up with 10 units with a 1:10 dilution. Greg L (my talk) 20:56, 4 December 2007 (UTC)
  • P.S. I answered your question as you intended the question, not as you actually wrote it. First off, if you dissolve a mass of a solid into a liquid solvent, you couldn’t properly use parts-per notation to express a volume-based ratio; only for a mass-per-mass ratio. Secondly, even if you could use parts-per notation to express the mass of a solid mixed into a volume of a solvent, dissolving solids into solvents doesn’t noticeably increase the volume of the solution. So you could start with 10 ml of water, add 1 g of a solid, and still end up with 10 ml of solution. Note too, that even with regard to the properly framed part of your question (liquid-to-liquid, volume-based mixtures), there’s a caveat: you wouldn’t use my above algebraic formula when adding strong acids to water. If you add 1 part pure HCl to 10 parts water, the acid doesn’t appreciably add to the volume of the water; you still end up with about 10 parts of the finish solution. If you dump a lot of acid in, it’ll change the volume only a little. For highly accurate work, you would put 3 parts acid into about 9–9.5 parts water, and would then top off to exactly 10 parts of finish solution to end up with a 30% mix on a volume basis. Greg L (my talk) 19:30, 11 December 2007 (UTC)

[edit] ppm to mg/l

I think it would be useful to state the relationship between ppm and mg/l.

It is something that I myself am not clear about and clarification is a good thing right?Velkyal (talk) 09:43, 2 April 2008 (UTC)

[edit] Maroon text

  1. This looks like a redlink.
  2. Don't depend solely on color to convey information.

Can we convert to some other format for these? — Omegatron (talk) 01:16, 21 May 2008 (UTC)

  • I underlined the text, which is a non-color based way to convey the distinction. Now color only facilitates the underlining (so it’s not solely color), and I changed from maroon to dark green. Greg L (talk) 23:14, 27 May 2008 (UTC)
That's fine by me. We'll see what others think. Thanks! — Omegatron (talk) 00:34, 28 May 2008 (UTC)

[edit] Wikilinks to billion, a disambiguation page

In order to avoid having this article link to the disambiguation page billion, I'm going to change the links to go to billion (word) which redirects to long and short scales, where there is a decent discussion of the ambiguity of the word billion. --AndrewHowse (talk) 14:17, 28 May 2008 (UTC)