Which statement about TLC analyses is not true? * A- The line at the base of the TLC plate should be drawn with a pencil. B- To prevent contamination, a new capillary tube should be used to apply each sample. C- Samples should be applied multiple times in the same place to increase the concentrations of any possible compounds in the spot. D- A glass beaker lined with filter paper can be used as a development chamber in a TLC analysis. E- All these statements are correct.

Which statement about TLC analyses is not true? * A- The line at the base of the TLC plate should be drawn with a pencil. B- To prevent contamination, a new capillary tube should be used to apply each sample. C- Samples should be applied multiple times in the same place to increase the concentrations of any possible compounds in the spot. D- A glass beaker lined with filter paper can be used as a development chamber in a TLC analysis. E- All these statements are correct.

EBK A SMALL SCALE APPROACH TO ORGANIC L

4th Edition

ISBN:9781305446021

Author:Lampman

Publisher:Lampman

Chapter89: Thin-layer Chromatography

Section: Chapter Questions

Problem 1P

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Similar questions

Although TLC is qualitative and tells you what is present in a given sample, it can also be used to determine where a compound might be lost: What samples could you test on a single TLC plate that might give you this information?
There were 2 spots on the TLC that did not match up with any of the standards. What were the Rf values of these spots? Identify what these chemical species might be and draw their structures. Solvent was 3:1:1 n-butanol/acetic acid/water. First plate is TLC plate 1. Second plate is TLC plate 2.
A TLC analysis is performed on both crude and purified biphenyl. Upon visualization under the UV- lamp both spots remain at the baseline. This is likely because: a. Biphenyl is a polar molecule and therefore should remain at the baseline upon TLC plate development in the proper eluent. b. The samples were not spotted properly on the TLC plate. c. The solvent was too non-polar. d. The solvent was too polar. e. The solvent evaporated before the TLC plate could be added to the chamber.
What is the purpose of placing a filter paper inside a beaker or developing chamber for TLC? Among the three solvents used in the separation of pigments in spinach, which produced the most effective separation? Explain your choice using at most three sentences. a.hexane b.70:30 hexane:acetone c. 50:50 hexane:acetone
Before developing a TLC plate you should _______.a. Make sure to mark the origin with a pen b. Make sure to mark the origin with a pencil c. Make sure the filter is all the way around the inside of the developing chamber
What is the purpose of thin layer chromography lab? What is a hypothesis I can use when conducting a TLC lab and how can that hypothesis be tested?
1. Which property of compounds is responsible for the separation in a TLC? Explain with an example.2. How does the separation occur during a TLC? (Hints: TLC plate and silica layer)
The following are the uses of TLC except Choices: Determine the number of components in a sample Detect a given compound or compounds in a very crude mixture Determine the concentration of certain components of the mixture Find suitable conditions prior to running a column chromatogram None of the above
What happens if the spots are made too large when preparing a TLC plate for development?
Compare and contrast a column chromatography, TLC, and GC according to stationary phase, moving phase, recovery of sample, size or amount of sample. You could make it into a table.
A chemist was able to extract a biologically active compound and wants to purify the sample since he is sure that the sample still contains impurities. After running the extract in TLC, the chemist found out that the sample produced only one spot near the solvent front. Suggest how the chemist can achieve a better resolution for the chromatogram.
Based on TLC, how can you tell if the reaction is complete and what is the relevvance of the multiple marks in the lanes of the tlc? PROCEDURE To a six inch test tube was added thiamine hydrochloride (0.65 g), followed by water (2mL). The mixture was gently shaken until homogeneous, and then ethanol (7.5 mL)was added. Finally, sodium hydroxide (10%, 1.5 mL) was added and the mixture wasgently stirred to ensure complete mixing.Benzaldehyde (3.8 mL) was then added at room temperature in one portion with gentlestirring. The pH of the resulting reaction mixture was determined and adjusted to >10by dropwise addition of 10% sodium hydroxide. The reaction mixture was then partiallysubmerged in a 65 °C water bath2 and the progress of the reaction was periodicallymonitored by TLC analysis.Once TLC analysis indicated that the reaction was complete, the reaction mixture wascooled to approximately room temperature, and then chilled in an ice-water bath. Theresulting precipitate was collected by…