Peptides and Amino Acids.docx

The methanol reacted slowly necessitating the ta to

Info icon This preview shows pages 3–4. Sign up to view the full content.

The methanol reacted slowly, necessitating the TA to produce an example methanol, in which the methanol reacted with the permanganate by turning thick and brown. The aspartame solution did not react, nor did the water control group. For the Ceric Ammonium Nitrate test, the intent was to indicate the presence of alcohol groups. Solution 4 turned orange immediately, while the methanol, already being an alcohol and acting as a positive control group, turned red immediately. The aspartame solution did not react, nor did the water group. The most likely possible error in this experiment is seen in the use of the diet soft drink in the solutions. The soft drink was not fresh, as it was mostly empty from use an undetermined amount of times, as well as having been left open for an undetermined amount of time. This leads to the possibility that the aspartame in the soft drink had hydrolyzed into diketopiperazine, also known as DKP. This is supported by the failure of many of the solutions in the permanganate and ceric nitrate qualitative tests, especially the ceric nitrate test for alcohols. This could also be a possibility for the “Fresh Aqueous Aspartame” solution, as this solution did not react with the qualitative tests either. Another possible error in this experiment could be found when measuring the solvent front. The ruler had touched each TLC plate a few times due to human error, and this could have contaminated the TLC plates, leading to misleading spots showing upon dipping the solution in ninhydrin and drying with the heat gun. Conclusion In Experiment 11, peptide bonds and amino acids, as well as artificial sweeteners such as aspartame, were investigated using qualitative tests and TLC plates. These tests showed the polarity of the solutions used, as well as tested the presence of particular bonds and functional groups between the solutions.
Image of page 3

Info icon This preview has intentionally blurred sections. Sign up to view the full version.

Colton Aleman CHEM 238-516 TA: Jialuo Li Tables and Figures Spot Spotting Solution 1 3 times Solution 1 (Aspartame) 2 1 time Solution 2 (Phenylalanine) 3 1 time Solution 3 (Aspartic Acid) 4 12 times Solution 4 (Hydrolyzed aspartame) Table 1: TLC Plate 1 Spot Spotting Solution 1 12 times Solution 5 (Beverage A) 2 12 times Solution 6 (Beverage B) 3 12 times Solution 7 (Beverage C) 4 3 times Solution 1 (Aspartame) Table 2: TLC Plate 2 Spot Solution Distance R f - Solvent 4.31 cm - 1 Solution 1 (Aspartame) 2.07 cm 0.48 2 Solution 2 (Phenylalanine) 1.92 cm 0.45 3 Solution 3 (Aspartic Acid) 0.67 cm 0.16 4 Solution 4 (Hydrolyzed Aspartame) 1.60 cm 0.37 Table 3: TLC Plate 1 Rf Values Spot Solution Distance R f - Solvent 4.17 cm - 1 Solution 5 (Beverage A) 2.95 cm 0.71 2 Solution 6 (Beverage B) 3.21 cm 0.77 3 Solution 7 (Beverage C) 1.90 cm 0.46 4 Solution 1 (Aspartame) 2.31 cm 0.55 Table 4: TLC Plate 2 Rf Values
Image of page 4
This is the end of the preview. Sign up to access the rest of the document.
  • Fall '07
  • Staff
  • Soft drink, ninhydrin solution

{[ snackBarMessage ]}

What students are saying

  • Left Quote Icon

    As a current student on this bumpy collegiate pathway, I stumbled upon Course Hero, where I can find study resources for nearly all my courses, get online help from tutors 24/7, and even share my old projects, papers, and lecture notes with other students.

    Student Picture

    Kiran Temple University Fox School of Business ‘17, Course Hero Intern

  • Left Quote Icon

    I cannot even describe how much Course Hero helped me this summer. It’s truly become something I can always rely on and help me. In the end, I was not only able to survive summer classes, but I was able to thrive thanks to Course Hero.

    Student Picture

    Dana University of Pennsylvania ‘17, Course Hero Intern

  • Left Quote Icon

    The ability to access any university’s resources through Course Hero proved invaluable in my case. I was behind on Tulane coursework and actually used UCLA’s materials to help me move forward and get everything together on time.

    Student Picture

    Jill Tulane University ‘16, Course Hero Intern