You need to know the molecular weight of the hydrogen peroxide in grams per mole and what final volume you want. Then just do the math.

You'll want to make it fresh since hydrogen peroxide degrades very quickly.

Hello,

How will I calculate?

First of all I need to know the molarity of my H2O2 solution. For this I will need the density of H2O2 which is 1.11kg/L or 1111 g/L. this means that m = 1111* 0.3 (30%) = 333.3 g in 1 liter of solution.

n = m/M.

M of H2O2= 34.01g/mol

so n = 333.3/34.01 = 9.80 mol/L. So your solution is 9.80 M.

Then, to prepare a 75 µM solution you dilute the solution which is 9.80 M using the rule CiVi = CfVf

H2O2 is unstable and is frequently sold (in a fresh bottle) at a little greater than the strength disclosed on the label to allow for decay (the vented cap is to stop older bottles from exploding due to oxygen gas buildup. I used this method:- H202 were prepared daily from serial dilutions of a known concentration assuming an extinction coefficient of 81 M -1 cm -1 at 230 nm. Reference for the extinction coefficient of H2O2 at 230 nm is:-

Homan-Muller, J.W.T., Weening, R.S. and Roos, D. (1975) Production of hydrogen peroxide by phagocytizing human granulocytes. J. Lab. Clin. Med. 85, 198--207.

More details of this method ,and other methods for determining H2O2 levels (and necessary precautions required for accuracy when using hyper-sensitive fluorescent H2O2 assays) can be found in my PhD thesis

Thesis Nitrofurazone and Hydrogen Peroxide Metabolism in Trypanosoma brucei.

and in some of my related publications from the mid-late 1980s.