CHM235 LAB NOTES EXPERIMENT #11

CHM235 LAB NOTES EXPERIMENT #11 - 2 mm diameter (per...

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CHM235 Exp. # 10 - Supplementary Notes (Pavia, 3rd ed.): TLC Analysis of Analgesic Drugs (p. 115-119) Execution Notes: 1. Set up the two TLC plates as indicated below: 2. Plate -A Key: 1 - acetaminophen 2 – aspirin 3 – caffeine 4 - ibuprofen 5 - salicylamide R  –  reference:   all five U - your unknown (select one : A,B,C,D,E) Plate - B   1    2     3     4     5      R       U      R      U      R      U a.½ tab (crushed) + 2.5mL ethanol (absolute) + 2.5 mL methylene chloride in a test tube b. Heat in a hot water bath (approx. 80-85 °C – the 100 °C recommended in the lab text sometimes causes the sample to boil over) c.Let cool & insolubles settle; transfer clear supernatant to a small screw-capped vial. 4. Use prepared capillary tubes (per Fig. 14.3, p. 702) for spotting--use repeated spot (quick touch)/dry cycles, keeping spot to < 1-
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Unformatted text preview: 2 mm diameter (per technique, p. 703). 5. Use beakers (with filter paper liners) for elution chambers--keep ethyl acetate/acetic acid (99.5:0.5) solvent level below sample spots on plate when inserted into beaker; cover with foil and let stand in hood until solvent front reaches within 0.5 cm of top of plate. Remove plate and lay on paper towel to dry &amp; immediately mark solvent front with pencil 6. Visualize eluted compounds in two ways: d. View under UV (short-wavelength light)--note colors, whether fluorescent or quenching, and outline spots with pencil e. Place in beaker with I2 crystals; cover with foil and place for two minutes in oven at 110 C. Return to hood to remove plate--observe colors and locations of spots. f. Measure Rf values (from starting line to spot centers) 7. Compare results with table on p. 108-109....
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CHM235 LAB NOTES EXPERIMENT #11 - 2 mm diameter (per...

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