Problem_Set_III_-_IntroductionToAnalyticalSeparations-Key

# Problem_Set_III_-_IntroductionToAnalyticalSeparations-Key -...

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Problem Set I II – Introduction to Analytical Separations 1. (a) 247.5 mL (b) 9.1 mL × 3 = 27.3 mL 2. fronted peak due to overloading 3. Three extractions with 100 mL are more effective. 4. pH 3 5. At higher pH, 8-hydroxyquinoline is ionized to L - , which forms a complex with a metal ion. The complex ML n is neutral and can be extracted into organic solvent. 6. a-C, b-D, c-A, d-E, e-B 7. The larger the partition coefficient, the greater the fraction of solute in the stationary phase, and smaller the fraction that is moving through the column. 8. (a) volume per cm of column = 3.14*(0.461 cm/2) 2 *1 cm = 0.167 mL Mobile phase volume = (1-61%)*0.167 = 0.0651 mL per cm of column Linear flow rate = (1.13 mL/min)/(0.0651 mL/cm) = 17.4 cm/min (b) t m = (10.3 cm)/(17.4 cm/min) = 0.592 min (c) K’ = (t r -t m )/t m t r = 10*0.592+0.592 = 6.51 min
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Unformatted text preview: 9. (a) 2.0 (b) 0.33 (c) 20 10. Solvent volume per cm of column = 0.15*3.14*(0.30 cm/2) 2 = 0.0106 mL/cm Linear flow rate = (0.20 mL/min)/(0.0106 mL/cm) = 19 cm/min 11. 0.6 and 6 12. 3.59 and 4.69 13. 603 and 0.854 14. (a) Column 1 (b) Column 2 (c) Column 1 (d) same (e) and (f) compound B 15. The linear flow rate at which solution goes past the stationary phase determines how completely the equilibrium between the two phases is established. This determines the size of the mass transfer term (C x ) in the van Deemter equation. The extent of longitudinal diffusion depends on the time spent on the column, which is inversely proportional to linear flow rate. 16. (a) 0.1 mm 17. Diffusion constants in gases are 10 4 times greater than those in liquids. 18. (a) 112 (b) 0.89 mm...
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## This note was uploaded on 05/09/2008 for the course PHARM.CHEM 306 taught by Professor Hu during the Spring '08 term at Rutgers.

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