Question

Post-Lab Questions 1. Why must you use a pencil, and not ink or felt-tip pen, to mark on the paper the origin of the spots of the amino acid preparations? 2. In this experiment, suppose you forgot to mark the position of the solvent front when you tested the hydrolysate of aspartame against the other amino acids. a. Is it still possible to determine how many amino acids were present in the hydrolysate? Explain your answer. b. Could you still identify what those amino acids were? Explain your answer. c. What can you not do? 3. There are polarity and molecular weight differences between aspartic acid and phenylalanine: Aspartic acid has a polar, acidic side chain and a smaller molecular weight; phenylalanine has a nonpolar side chain and a larger molecular weight. Based on the R values you obtained for these two amino acids in the solvent employed, which amino acid migrated faster and which of these two properties influenced the rate of migration? 4. From your experiment, is there any evidence that the aspartame in the Diet Coca-Cola sample showed any hydrolysis into the two amino acids? 465

Answer 1

Q1

Note that using any king of ink will interact in solution, since it is soluble in the solvent

Then, avoid any kind of pens/markers

use pencil, because it uses solid graphite (alloptrope of carbon)

it is inert with the materials being used, and will not form any kind of side reaction