Ron,
I think the mg/L to ppm conversions in the lecture are out by 3 orders of magnitude.
ppm is an ambiguous unit of measure as it can mean weight by weight (g/kg), weight by volume (mg/L) or volume by volume (uL/L). It is my understanding that the convention when discussing concentrations in liquids is ppm equals mg/L.
For the calculations, the "atomic mass" of NO<SUB>3</SUB> is 62, so 1 uM is 62ug or 0.062mg. 2uM/L would be 0.124mg/L or 0.124ppm. "Atomic mass" of PO<SUB>4</SUB> is 95, so 0.4uM/L is 38ug/L or 0.04mg/L.
I think the mg/L to ppm conversions in the lecture are out by 3 orders of magnitude.
ppm is an ambiguous unit of measure as it can mean weight by weight (g/kg), weight by volume (mg/L) or volume by volume (uL/L). It is my understanding that the convention when discussing concentrations in liquids is ppm equals mg/L.
For the calculations, the "atomic mass" of NO<SUB>3</SUB> is 62, so 1 uM is 62ug or 0.062mg. 2uM/L would be 0.124mg/L or 0.124ppm. "Atomic mass" of PO<SUB>4</SUB> is 95, so 0.4uM/L is 38ug/L or 0.04mg/L.
