Question

can you solve this for me, please

Place approximately 10 mg of each of the four reference compounds in labeled vials or 10 X 75-mm test tubes and dissolve the samples in a few drops of methanol. In a fifth tube place a quarter of an analgesic tablet and add 1 mL of methanol. Crush the tablet with a rod, stir well, and allow the insoluble material to settle. Note that aspirin is not stable in methanol, so fresh solutions must be made each lab period. TLC the samples as outined above. Mark the solvent boundary with a pencil mark or small scratch. Examine the chromatogram under a UV lamp and sketch the appearance of the plate in your notebook, indicating the location and approximate size of the spots and any distinctive col- ors. After this examination, place the plate in a jar of iodine vapor for approximately 30 sec- onds, including as many of the spots in the unknown lane as possible. From the identity and number of the spots in the unknown and the composition of the possible unknowns, deduce the identity of your unknown. remove, and again record the appearance. Identify the spots in the chromatogram, QUESTIONS Explain why it is important to develop a TLC plate is2 urated with the vapor of the developing solvent. Calculate the R, values for Compound A and Compound B from the following data: 1. closed container and to have the chamber sat- 2. SUBSTANCE Solvent Compound A Compound IB DISTANCE TRAVELED 12.8 cm 4.0 cm 7.5 cm What will be the result of the following errors in TLC technique? a. 3. too much sample applied b. solvent of too high polarity solvent pool in developing jar too deep d. c. forgetting to remove the TLC plate when the solvent has reached the top of the plate Explain why the presence of crystals of the sample at the starting point causes streaking of the plate during development. 4.

Answer 1

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