Ion Chromatography data mM -> mg/l?

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jigga^2
jigga^2's picture
Ion Chromatography data mM -> mg/l?

 Hi everyone, I have what I think is a simple question but I don't want to get confused...

I have obtained data from ion chromatography which gives me phosphate anion concentration in mM. I want to convert this to mg/l, is it as simple as mM = mmol/L = x MW mg/L?
Furthermore, at what point does one take dilution factors into account? The samples were diluted 10x. Example data is 0.2955 and 0.3062 mM.

Dr. Analytical
Dr. Analytical's picture
Your instrument reports units

Your instrument reports units based on how you enter your standards.  In the future, you could calibrate using the mg/L values for the standards.  

For the conversion, you are on the right path.  Use units conversion factors to change the units.

mM = mmol/L

mmol/L X (mg/mmol) = mg/L

the mg/mmol is the same as g/mol, which is the MW, as you stated.

For the dilutions, these are applied after the analysis.  So if the original sample was 10X more concentrated, then you should multiply the instrument value by 10.