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Final % DMSO Concentration - (Apr/11/2010 )

Hi!

I am quite unsure of what does it mean by e.g. 0.5% final DMSO concentration. I had tried googling around, but am unsure if I can correct in my interpretation of the calculations. If I had dissolved 50 ug powder into 50 uL DMSO to make a stock solution, that would give it 1% DMSO concentration. Then, if I was to use 10 ug of this stock, the final DMSO concentration would be 0.2%. Is this correct?

Thank you for any help provided.

-Isy-

Hi Isy.
FINAL DMSO concentration means the concentration of DMSO in your working solution e.g. your media, buffer ect.
When you dissolve whatever powder in DMSO you will get a stock solution made up of 100% DMSO!


0.5% final DMSO concentration means you give 0.5 ml of this stock solution to 99.5 ml of water (0.5 ml/100 ml*100 = 0.5%).

Now you have to combine this with the desired molarity of the stuff you dissolved: e.g. 0.5 ml of a 1 M stock of stuff X in DMSO pipetted in 99.5 ml water will give you a 5 mM working solution with again 0.5% DMSO final concentration.

Itīs important to consider the final concentration of your solvent because solvents as DMSO can have side effects depending on concentration and biological material used.

-SAnna-

I see, I see. Thank you for the explanation.

So, if I have a stock solution of 1mM Dye X in 100% DMSO and I use 20 uL of it in 10 mL of medium (final Dye X concentration = 2 uM) , then the final DMSO concentration in the working solution is 0.2%. Is that correct?

-Isy-

Right! ;)

If you need the corresponding formulas have a look into "Useful Dilution Techniques & Calculations" under "general lab techniques".

-SAnna-

Isy on Apr 12 2010, 03:27 PM said:

I see, I see. Thank you for the explanation.

So, if I have a stock solution of 1mM Dye X in 100% DMSO and I use 20 uL of it in 10 mL of medium (final Dye X concentration = 2 uM) , then the final DMSO concentration in the working solution is 0.2%. Is that correct?



20ul of DMSO into 10 ml of medium is a 1:500 Dilution

A 1:500 Dilution of a 100% DMSO Solution = 0.2%

100% DMSO = 100g of DMSO in 100ml of aqueous


However 0.2% DMSO final concentration is too high for any cellular experiments. In my experience you should always be below 0.1% DMSO

Hope this is useful

Kindest regards

Uncle Rhombus

-rhombus-

Thanks for adding this for clarity!
Nevertheless when you use DMSO e.g. as solvent for X-Gluc in a GUS assay with plant material, 0.2% or even higher is just fine. ;)
It really depends on what you wanna do with it, Isy

-SAnna-

Thanks for showing a shorter method to calculate it. :D

I'm using DMSO to dissolve the dye for Calcium flux assays. The protocol in the Current Protocols in Cytometry mentioned to keep it under 0.5%.

If I would like to adjust the final DMSO concentration to 0.1%, the variable that I need to change is the DMSO volume to dissolve the dye? The final dye concentration has to be 2uM and I get that from the 1mM stock (100% DMSO).

-Isy-