You get a spectre of test compound. Determine the wavelength of maximum absorption of the solution. Gradually dissolve the suspended portion of your compound. Build the intensity of maximum - the concentration of compound Find the concentration when the solubility is no longer moving. This is solubility constant.
You get a spectre of test compound. Determine the wavelength of maximum absorption of the solution. Gradually dissolve the suspended portion of your compound. Build the intensity of maximum - the concentration of compound Find the concentration when the solubility is no longer moving. This is solubility constant.
You must to prepare a calibration curve by plotting of substance concentrations versus absorbency of substance at λmax. A linear relationship is obtained and the slope is calculated from the graph. Depending on its absorbance , the unknown solubility of your substance is determined as following:
dissolve a large portion of your substance into solvent ,mix and stir until it will not dissolve further amount and a saturated solution is approaches, filtration or centrifugation is necessary to remove non-dissolved material. Determine the absorbance of clear solution at same λmax. Now you can calculate the concentration(solubility) by applying following relationship:
[substance]=absorbance at λmax/slope
Then it is easy to calculate Solubility Product Constant, Ksp