[jackscholar]

I have a fairly big problem with an experiment I am conducting. I want to make a standard curve with resveratrol. One tablet contains 100mg of this substance. I want to make a 100mL or 1L stock solution where the 100mg is diluted to a concentration such that it is equivalent to 1mg.

I don't think I did my calculations right because i simply added 1 tablet (100mg) to 100mL hoping it would produce a 1:1 ratio such that 1mg:1mL (for a 100mL solution). There were insoluble compounds so I filtered them off. The problem present is this: resveratrol has a solubility of 0.03g/L and therefore 3mg/100mL. I heated the solution to increase the solubility by I know that it won't be anywhere near 100mg.

1) was my statement of the 100mg:100mL correct? If not how can I fix this up
2) how much will the solubility effect the amount of resveratrol in the water. Can I fix this in any way?

[Borek]

concentration such that it is equivalent to 1mg.

1mg per ... ?

was my statement of the 100mg:100mL correct? If not how can I fix this up

Yes, that was (in general) the correct idea, even if it was not because of the solubility problems.

how much will the solubility effect the amount of resveratrol in the water. Can I fix this in any way?

It will limit maximum concentration of your solution, but as we don't know what is your intended concentration nor intended application, it is hard to say anything.

[jackscholar]

I want the concentration to be 1mg/L. The problem is that most literature states the concentration as a mg/L amount.
The amount i want as a concentration would then be C=amount/molecular weight
I want my concentration to be 1mg so that would be C=0.001/228.24 C=4.38*10^-6 moles.
The concentration I do have per tablet is 4.38*10^-4 moles.

I wanted to have my concentrations in terms of mg/L instead of moles because i thought it would be easier to relate to what I am reading.

I want to do a UV spectro test on this solution in order to make a calibration curve for wine sample. I know there are better method but I don't have access to them unfortunately. I'm just worried that now I can't test the sample properly because the amount hasn't been properly dissolved into the water, meaning I filtered it off.

What i originally wanted to do was make a 100mL 1mg/L (4.38*10^-6M) stock solution from 100mg of resveratrol. Then I wanted to make other solutions where they were 9 parts (9mL) stock solution and 1 part (1mL)  and continue to do so to make a concentration curve from 0.1mg/L to 1mg/L.

[Borek]

I want the concentration to be 1mg/L.

OK

I want my concentration to be 1mg

The concentration I do have per tablet is 4.38*10^-4 moles.

You are ignoring volumes, which makes your statements meaningless.

I wanted to have my concentrations in terms of mg/L instead of moles because i thought it would be easier to relate to what I am reading.

Makes sense.

I'm just worried that now I can't test the sample properly because the amount hasn't been properly dissolved into the water, meaning I filtered it off.

What i originally wanted to do was make a 100mL 1mg/L (4.38*10^-6M) stock solution from 100mg of resveratrol.

You can always try to crush your tablet and use only part of it. Or, if it doesn't interfere with your plans, dissolve the tablet in other solvent, miscible with water, and transfer only part of the volume to your water solution.

[jackscholar]

This may be a bit off topic but, if I mixed 100mg of the compound into a 100mL water solution, then filtered it, would I then have a 3mg/100mL solution of that compound. From there could I then use dilution formulas to convert that into a 1mg/L solution?

[Borek]

Assuming you can trust the solubility data, then yes, using saturated solution is one of the ways of dealing with solution preparation. But you have to be suer you know exact solubility and exact temperature. Plus, solubility can depend on other factors, like pH.