How to make stock solution?

[mcdeena]

Hi, I need to dissolve curcumin in 0.5% DMSO. Does that means 100mg of curcumin in 0.5mL DMSO?
Thanks

[danfive]

No you can make 0.5% DMSO by diluting into water.
Their densities are about the same so 0.5% v/v or w/w will be very similar anyway.

You should figure out the concentration of curcumin before deciding the volume of 0.5% DMSO.

[mcdeena]

I usually dissolve 0.02g extract in 1000 microlit pure DMSO as stock solution.

For dilution, I add 10 microlit of the stock to 90 microlit of 10% DMSO in tubes. From there, I transfer 10 microlit from the tube + 190microlit cell suspension in the well. This will gives me 100mcg/mL concentration.

But I have read in the forum shouldn't exceed 0.5% DMSO for cell culture work. My problem is how do I calculate the final concentration of DMSO here?

Sorry. Sounds very stupid but my chemistry is very rusty.

[danfive]

Originally Posted by mcdeena

I usually dissolve 0.02g extract in 1000 microlit pure DMSO as stock solution.

For dilution, I add 10 microlit of the stock to 90 microlit of 10% DMSO in tubes. From there, I transfer 10 microlit from the tube + 190microlit cell suspension in the well. This will gives me 100mcg/mL concentration.

But I have read in the forum shouldn't exceed 0.5% DMSO for cell culture work. My problem is how do I calculate the final concentration of DMSO here?

Sorry. Sounds very stupid but my chemistry is very rusty.

I'll try to calculate, for you

stock = 1 ml 100% DMSO (w/curcumin dissolved)
1st dilution 1:10 = 10% DMSO
2nd dilution (into cell culture) 1:20 = 10% *1/20 = 0.5% DMSO (w/curcumin dissolved)

for curcumin conc'n in g
stock = 0.02g/1ml
1st dil'n 1:10 = 0.002g/ml
2nd diln 1:20 = 0.002g/ml *1/20= 0.0001g/ml or 0.1 mg/ml

Hope that helps.

[danfive]

Originally Posted by mcdeena

For dilution, I add 10 microlit of the stock to 90 microlit of 10% DMSO in tubes. From there, I transfer 10 microlit from the tube + 190microlit cell suspension in the well. This will gives me 100mcg/mL concentration.

Didn't notice that underlined part the first time.
I don't think you need to dilute into 10% DMSO just use molecular grade water.
I think you are ending up with

%DMSO = (10 *100%/100) + (90*10/100) = 10% + 9% = 19%DMSO at 1st dilution.
Makes sense because 90ul at 10% would be 9ul of DMSO + 10ul 100% DMSO = 19ul of DMSO / 100ul total volume

Like I said you don't need to dilute into 10% solution, unless you can also dissolve the curcumin into pure water, then your method would work and give you the 0.5% DMSO final conc'n.

[mcdeena]

Danfive, thanks so much for your reply and the info. Yup, I managed to calculate the concentration of DMSO and figured out it's 0.5% as well Cheers.

[analyticalnews]

same question to you,but i think we can resolve it in this problem

[AllyAshantiBrown]

Dissolve 0.3 grams in 1 L.

[danfive]

Originally Posted by AllyAshantiBrown

Dissolve 0.3 grams in 1 L.

WTF?

[lu'lu]

Hi, I would like to know the best way to treat my cancer cells for apoptosis (in tissue culture dishes with 10^6 cells) with IC50 or should I use various concentrations? I have tried to treat with my IC50 and run the cell cycle analysis (24hrs), there is no cell death at G0.