Dear Aleksandar Dishkelov ,

you may got in trouble with the powers of 10,

especially for ml = milli-liter = 10-3l and µl = ul = micro-liter = 10-6l

and you erroneously divided two times by the MW.

For the conversion of 250pg into mol you have to divide that number by the MW of 183,2g/mol

so you have

250pg---> 250pg/(183,2g/mol) = 1,365pmol = 1,365*10-12mol

so 250pg/ml*) convert into

1,365*10-12mol/ml = 1,365-10-12mol/(10-3l) =

= 1,365*10-9mol/l = 1,365*10-3µmol/l = 1,365*10-3µmolar = 0,001365µmolar

*) Please bear in mind that 'ml' is 'milli-liter' and not 'micro-liter'

and molar is 'mol/l' and micromolar = µmolar = 10-6molar

Best regards

G.M.

Gerhard Martens Thank you very much for the explanation !