# How to calculate concentration of unknown saturated stock solution from diluted solution whose concentration is known?

I want to measure the solubility of a compound. I prepared a saturated stock solution of my compound in 100ml of water by dissolving it in excess and filtering out the undissolved sample.

Then I took 1ml of saturated solution, diluted it to 10ml and measured the absorbance on a UV spectrophotometer. After that I calculated the concentration of diluted solution by plotting a calibration curve of various solutions of known concentrations.

Now how can I calculate the concentration of my saturated stock solution from diluted one?

The concentration of diluted solution is 17ppm/10ml.

• First off, welcome to Chemistry.SE! You need to give more detail regarding your question and experimental details, and you also need to show what you've tried yourself so far. For a homework question, this is a requirement. Also, people will be more motivated to help you when they see more effort on your part. For a good outline of the homework policy, see here. Feb 2 '17 at 5:10
• Unless I misunderstood (please give more info), you've already done the most difficult part of the job by determining the concentration of your diluted solution! And you just diluted your stock solution ten times, so you'd only have to multiply by ten the value that you found for your diluted concentration... Feb 2 '17 at 14:50
• 17 ppm is a concentration. It doesn't matter if you have 10 ml of it or 1 L. It is still 17 ppm.
– MaxW
Feb 2 '17 at 14:55