## ppm to mg/l conversion? & expressing concentration by percentage

bluamine - 29-3-2016 at 06:40

Hi everyone!!
I need to convert concentration from ppm to mg/l. In addition i would like to know what's considered when we use percentage concentration mass or volume??

blogfast25 - 29-3-2016 at 06:55

 Quote: Originally posted by bluamine Hi everyone!! I need to convert concentration from ppm to mg/l. In addition i would like to know what's considered when we use percentage concentration mass or volume??

1 ppm = 1 part per million (all by weight).
1 mg/l = 1 mg per 1000 g (in the case of water) = 0.001 g per 1000 g = 1 ppm.

Percentages can be by volume or weight, resp. w% and V%. E.g. 5 w% = 5 g of solute per 100 g of solution.

bluamine - 29-3-2016 at 10:31

Quote: Originally posted by blogfast25
 Quote: Originally posted by bluamine Hi everyone!! Percentages can be by volume or weight, resp. w% and V%. E.g. 5 w% = 5 g of solute per 100 g of solution.

Thank you for answering my first question.
About the second one i'm supposing that the percentage would be by weight if the solute was solid. otherwise it would be by volum!!e (especially when it comes to liquid solutes like acetic acid) but i'm not sure if it was a gaz (hydrochloric acid for exp)

feacetech - 29-3-2016 at 19:20

mass never lies

the terms w/w or w/v tell you what type of percentage you are using

mg/L divided by 10000 yields percentage

Ozone - 29-3-2016 at 20:02

ppm (ug/g, mg/kg, whatever) / 10000 = % w/w. 1E6 ppm = 100%. Stick with mass, and you'll be OK. Otherwise, be prepared to make many error propagating approximations (or measurements) of density for the sake of correction.

O3

gsd - 29-3-2016 at 22:03

One quick thing to remember is:

0.1 % = 1000 ppm

gsd

dhaffnersr - 30-3-2016 at 15:30

Hey Bluamine, here is a niffty website that can make it easy;

http://www.lenntech.com/calculators/ppm/converter-parts-per-...

hope this helps have a good one!

Dave H