For a 100mL solution, mix 5mL of DMSO with 95mLs of water/PBS or other solutions I suppose.

Abhilek Kumar Nautiyal , you need to specify if the percentage of DMSO is 5% w/v or 5% v/v. If it is the latter and you want to prepare 100 mL of the solution with a rigorous method, follow the following procedure:

1. Take 5 mL of pure DMSO with a volumetric pipette and transfer it to a 100 mL volumetric flask.

2. Add the solvent (your question does not make it clear if your solution is aqueous) on a volumetric flask until the mark is completed.

If you only need an approximate preparation without much rigor, the method that recommends Dario Pacitti would be fine.

Postscript: fatty acids and naphthalene are poorly soluble in water, in what range of concentrations do you plan to work?

José Luis Duque-Rivera

I have to prepare this ..

Fatty-acid substrates were dissolved in DMSO (used at 10%, v/v,

final concentration)

Let me see if I understand correctly: were the fatty acids dissolved in pure DMSO and now you want to prepare a new solution in which the previous solution is 10% and the water is 90%?

No i want to dissolve my substrate which is solid in 10 % dmso soln

I get it.

Then you can follow the procedure of Dario Pacitti to prepare approximately 100 mL of solution: 10 mL of DMSO and 90 mL of water and then dissolve the fatty acids.

If when dissolving the fatty acids in 10% v/v DMSO you get a cloudy solution, I recommend that you try an alternative procedure:

1. Prepare a solution of 10X fatty acids in pure DMSO (solution 1).

2. Place 10 mL of solution 1 in a beaker, shake vigorously with a magnetic stirrer and slowly add 90 mL of water.