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:

ppb - just a stub
Parts per billion - also a stub which duplicates the above
ppt - redirects to concentration

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

Parts per trillion - just a stub

--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)

1 2003-2004 discussion
2 Examples
3 Other uses
4 absolutely confusing
5 Notes

[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 ?

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)

[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)