4 replies to this topic

[harry348]

I have 25g of dry powder that I need to convert to a 10mg/ml solution.
can anyone help me out in this

[pito]

harry348, on 13 July 2011 - 01:13 PM, said:

I have 25g of dry powder that I need to convert to a 10mg/ml solution.
can anyone help me out in this

you need 10mg per ml... so if you take 10mg and dissolve this in 1ml .. you have 10mg per ml..

Now the thing is: you have 25 gram... so how does 25 gram corrolates to the volume?

10mg ======> 1 ml
25 mg =====> 1 ml x 2,5 = 2,5ml   (multiply by 2,5 because you went from 10 to 25 mg)
25.000mg (25g) =====> 2,5ml x 1000 = ...  (multiply 1000 because you go from 25mg to 25.000mg)


Its basic math...

think about it.. see if you understand it.

[toptea]

Hi Veteran,

please help me as well. I need to make a buffer  of this proportions (100 mM Tris, pH 7.4, 0.1 M KCl, 1 mM EDTA, 1 mM PMSF) and dont know exactly how much quantities of each reagent should be mixed..I think its a basic technique as well. Thanks

[phage434]

If I were making this up, I would first make (or better, find in the lab) stock solutions:
1M Tris Cl, pH 7.4
1M KCl
500 mM EDTA pH 8.0
100 mM PMSF in isopropanol (careful, highly toxic!)

I would mix 1 liter of my desired buffer by mixing 100 ml Tris, 100 ml KCl, 2 ml EDTA, and 10 ml PMSF solutions, and make the total up to 900 ml.  Check the pH, possibly correct, and top off to 1 liter.

[toptea]

Thank you so much for the help....