[Greshym]

Hi All

I am having issues regarding the dilution for a w/v % for an ICP we are reporting as mg/L

I am diluting 10g/100 then further to 1:500 dilution, another chemist that I work with is insisting that the this should be a w/w% for a mg/L result, and has diluted with 10ml/100 to a 1/500 dilution. te density is not 1 and i have tried to explain this to them, with dismal results.

am i going mad?? or am i correct with my diluton being w/v%??

Thanks all

[Borek]

I am diluting 10g/100

What is what of what here?

What is 100?

[Greshym]

sorry, its 10g/100ml then a further 10ml in 500ml (so ends up as 1g/500ml) as a serial dilution

[Borek]

mL of what? There is a chance you are right, but you are leaving out so many crucial information there is no way to answer.

For water (with the density of 1 g/mL) w/w is typically so close to w/v the distinction doesn't matter.

For other solvents it can't be ignored. 1 g/1000mL solution of acetic acid in water is 1000 ppm w/w, but 1 g/1000 mL solution of acetic acid in ethanol is 1265 ppm w/w. Both solutions are 1000 ppm w/v.

[Greshym]

Thanks for the info. we are diluting with water, however the sample has a density of 1.10.  But you have answed my question.
Thank you

[Borek]

Density of the original sample - as long as you take 1 g of it, not 1 mL - doesn't matter.