CHM235 LAB NOTES EXPERIMENT # 9 - stations in the hoods by...

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CHM235 Exp 7 (Pavia, 3rd ed.): Isolation of the Active Ingredient in an Analgesic Drug (p. 96-99) 1. DAY ONE: In addition to the "Required Reading" cited on p. 97, the essays on "Aspirin" (p.100-102) and on "Analgesics" (p.105-109) are also recommended. 2. Remember to PRE-WEIGH your tablets, and mechanically remove as much coating material, if present, as possible prior to starting the extraction. 3.[p.97, para 2]: Skip the cotton in the "filter tip pipet" described in the experiment. Use an ordinary Pasteur pipet. Remember to Depress the bulb of the pipet BEFORE inserting into the solution so as not to disturb the solids that have settled out. 4. [p.97, para 3]: Be SURE the centrifuge is balanced before use. 5. [p.98, para 1]: Skip the ENTIRE section on Column Chromatography. Instead, if necessary, filter your centrifuged liquid sample through a Pasteur pipet into which has been inserted (with a wire or applicator stick) a plug made of 1 cm x 1 cm of Kemwipe tissue 6.[p.98, para 3, p.99, para 1]: Use one of the evaporation
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Unformatted text preview: stations in the hoods by clamping your vial into a water bath under a Pasteur pipet, through which you can direct a stream of air [see Fig. 3.12, p. 542]. 7.[p.99, para 2]: Skip the Vacuum filtration step; it should not be necessary. When the solvent is gone, scrape the isolated solid* onto a piece of filter paper. Fold the edges carefully around the sample and tape closed. Store in a labeled beaker and place on the sample collection tray. *NOTE: The ibuprofen samples may appear glassy rather than crystalline; either scratch with your microspatula to induce crystallization or place in a beaker of ice. 8. Day TWO : a. Scrape your "dried" sample onto a pre-tared weighing paper and obtain the mass of isolated solid. Use this weight (along with the initial weight of your tablets) to calculated the % recovery of your active ingredient. b. Determine the melting point on the crushed, dried crystals you isolated. c. Place your product in a small vial, labeled with your team members....
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