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Concentration calculation of disodium salt standard

Posted: Fri Mar 30, 2012 6:27 pm
by arobles
Hi

I am analyzing ATP by reverse phase HPLC. I want to calculate the concentration of ATP in a sample using as reference the calibration curve of the standard (ATP disodium salt). My question is the following: Do I have to subtrac the sodium weight from the molecular weight of the standar? before to calculate the ATP concentration of the samples.

Thanks!

Re: Concentration calculation of disodium salt standard

Posted: Fri Mar 30, 2012 7:19 pm
by JGK
use a correction factor based on MW

Factor = MW ATP/MW sodium salt

weight of sodium salt X factor will give you the weight of ATP present (assuming 100% purity)

Re: Concentration calculation of disodium salt standard

Posted: Sat Mar 31, 2012 12:52 am
by arobles
thanks a lot!

Re: Concentration calculation of disodium salt standard

Posted: Sun Apr 01, 2012 9:32 pm
by lmh
things like that I prefer to express on a molar basis (which often makes a lot more sense anyway. Who has ever quoted the Km of an enzyme in mg/mL??). That way I can calculate the molar concentration of my standard based on whatever salt I buy, and my reader (assuming anyone reads anything I write) can't get it wrong...