Chemical Forums
Chemistry Forums for Students => Undergraduate General Chemistry Forum => Topic started by: Eventhorizon90 on December 15, 2015, 10:32:14 AM
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I'm a physics student and doing a course in biophysics. I would really appreciate it, if you would take some time and provide some hints as to how to design a more concrete plan. Especialy, how do I find out the partition coefficient from system A and B?
Solubility of CPZ in DMSO: 71 mg/mL
Molecular weight of CPZ: 355,33 g/mol
Dissolve 17,7665 mg CPZ in 50 mL DMSO to obtain a 1 mM solution.
Prepare a series of samples of pentane with the following volumes (1 ml, 5 ml, 10 ml, 20 ml, 40 ml) and bring 10 ml of the CPZ+DMSO solution into contact with it.
Shake the solutions to ensure fast equilibration and then centrifuge to separate the two phases.
Use UV-vis to measure the absorbance of chlorpromazine in DMSO and use the absorbance to determine the final concentration of CPZ in pentane. Measure the absorbance between ~200-380 nm.
Use LB to determine the concentrations of each solvent to determine.
The partition coefficient of system B is defined as the difference in concentration between CPZ in DMSO in system A and the amount of CPZ that has diffused to pentane.
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I have not done this myself; therefore, nothing I say should be construed as expert advice. The definition of partition coefficient that I learned from my organic techniques textbook was that it was the ratio of concentration in solvent S to solvent S'. I am not sure whether or not your definition is the same. What is LB? Obviously you will need two extinction coefficients, one for each solvent. Also, I am not quite sure how you will deal with having multiple determinations of K, the partition coefficient. Do you plan to average them?