A sample of cocaine is submitted to a Toxicology lab and is tested on a TLC...
Homework Answers
The cocaine sample is highly nonpolar, so that one can't observe in a UV lamp.
But the IR can be done, due to the presence of two ester linkages present in cocaine.
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A sample of cocaine is submitted to a Toxicology lab and is
tested on a TLC...
3) What two methods of visualizing spots on the TLC plate will you use in this lab? Why would you predict that the...
3) What two methods of visualizing spots on the TLC plate will you use in this lab? Why would you predict that the elution solvents (hexanes or ethyl acetate) would not be visible under UV visualization?
In our Thin-Layer Chromatography Lab, we were asked to determine the components of Excedrin by analyzing...
In our Thin-Layer Chromatography Lab, we were asked to determine the components of Excedrin by analyzing the development of aspirin, acetaminophen, and caffeine on a TLC plate and compare it to Excedrin's development. Pure ethyl acetate was used as the solvent, and each analyte was mixed with 95% ethanol. Unfortunately, our professor suspected that our TLC plates were old/deteriorated as every group was unable to detect CAFFEINE or ASPIRIN with a UV lamp, but ACETAMINOPHEN and EXCEDRIN were easily detected...
TLC Analysis Of Egg Lipids Lab 1. The TLC plates were pre-baked at >120C. Why is...
TLC Analysis Of Egg Lipids Lab 1. The TLC plates were pre-baked at >120C. Why is this step necessary? 2. Below is the structure of your lipid staining dye, Naphthol Blue-Black. Explain which noncovalent interactions would be most important in allowing the dye to adhere to lipids (consider the chemical property of lipids as well as the dye). 3. You ran a solution of a fatty acid and a wax on a TLC plate using the exact conditions used in...
Or responds to 50% T. Using a ruler. Jr the sample cells tested and make a table to .1 mark) Whic...
c please
or responds to 50% T. Using a ruler. Jr the sample cells tested and make a table to .1 mark) Which cell material would be the best one to tise in the range we tested? (1 mark) ii) Why shouldn't a cell material be used for a wavelength below its cut value? (1 mark) b) Make a table listing the solvents tested and their UV-cut-off values. Based on your results, which is the best solvent to use in...
1) A student develops their TLC plate and places it under a UV light, but nothing...
1) A student develops their TLC plate and places it under a UV light, but nothing appears. What mistake might the student have made? a) Spotted the compound below the level of eluent b) Spotted the compound above the level of eluent c) Used a sample that was too concentrated d) Used too much sample 2)Thin layer chromatography, TLC, is commonly used to monitor reactions to completion. Using this technique, what would indicate to a student that the reaction is...
4. Consider the following silica gel TLC plac or compounds A, B, and hexines: developed in...
4. Consider the following silica gel TLC plac or compounds A, B, and hexines: developed in Fo-o- og a) Determine the Rr values of compounds A, B, and C run on a silica gel TLC plate using hexanes as the solvent b) Which compound, A, B, or C. is the most polar? values if you used acetone instead c) What would you expect to happen to the of hexanes as the eluting solvent? 5) Consider a sample that is a...
Please help answer questions for esterification pre-lab. 4. Why do we use DMSO to prep the...
Please help answer questions for esterification pre-lab.
4. Why do we use DMSO to prep the bio-sample rather than using Di water? (2 pts) 5. How does the KMnO4 stain detect the alcohol on the TLC plate? (2 pts)
1. A solution of the sample to be analyzed has been made in a suitable solvent...
1. A solution of the sample to be analyzed has been made in a suitable solvent and wil l be provided for you. With this solution, a small spot is applied at a distance hear the bottom of the edge of a TLC plate using an applicator. (see Figure 1) This spot must be above the level of solvent in the TLC chamber. Why? 2. The plate is placed in a developing chamber containing the appropriate solvent (eluent), covered, and...
I need help with my pre and post lab questions. The three compounds below were spotted...
I need help with my pre and post lab questions.
The three compounds below were spotted on a TLC plate and developed to give the TLC plate shown. Which compound corresponds to which spot? Calculate the Rf value for spot B in the TLC plate shown above. When using polarity to determine the relative rates at which organic compounds travel up the TLC plate, we are considering compounds of similar molecular weight. It should also be noted that Rf values...
3. A student is monitoring a reaction using TLC. The chemical reaction converts compound A into...
3. A student is monitoring a reaction using TLC. The chemical reaction converts compound A into compound B, and she uses molecule A as her reference. Compound A has an Rf value of 0.45; while compound B has an Rp of 0.68 in the solvent system being used. a. Draw a picture of her TLC plate at the beginning of the reaction. b. Draw a picture of her TLC plate after 50% completion (50% of the A molecules have been...
3) What two methods of visualizing spots on the TLC plate will you use in this lab? Why would you predict that the elution solvents (hexanes or ethyl acetate) would not be visible under UV visualization?
c please
or responds to 50% T. Using a ruler. Jr the sample cells tested and make a table to .1 mark) Which cell material would be the best one to tise in the range we tested? (1 mark) ii) Why shouldn't a cell material be used for a wavelength below its cut value? (1 mark) b) Make a table listing the solvents tested and their UV-cut-off values. Based on your results, which is the best solvent to use in...
4. Consider the following silica gel TLC plac or compounds A, B, and hexines: developed in Fo-o- og a) Determine the Rr values of compounds A, B, and C run on a silica gel TLC plate using hexanes as the solvent b) Which compound, A, B, or C. is the most polar? values if you used acetone instead c) What would you expect to happen to the of hexanes as the eluting solvent? 5) Consider a sample that is a...
Please help answer questions for esterification pre-lab.
4. Why do we use DMSO to prep the bio-sample rather than using Di water? (2 pts) 5. How does the KMnO4 stain detect the alcohol on the TLC plate? (2 pts)
1. A solution of the sample to be analyzed has been made in a suitable solvent and wil l be provided for you. With this solution, a small spot is applied at a distance hear the bottom of the edge of a TLC plate using an applicator. (see Figure 1) This spot must be above the level of solvent in the TLC chamber. Why? 2. The plate is placed in a developing chamber containing the appropriate solvent (eluent), covered, and...
I need help with my pre and post lab questions.
The three compounds below were spotted on a TLC plate and developed to give the TLC plate shown. Which compound corresponds to which spot? Calculate the Rf value for spot B in the TLC plate shown above. When using polarity to determine the relative rates at which organic compounds travel up the TLC plate, we are considering compounds of similar molecular weight. It should also be noted that Rf values...
3. A student is monitoring a reaction using TLC. The chemical reaction converts compound A into compound B, and she uses molecule A as her reference. Compound A has an Rf value of 0.45; while compound B has an Rp of 0.68 in the solvent system being used. a. Draw a picture of her TLC plate at the beginning of the reaction. b. Draw a picture of her TLC plate after 50% completion (50% of the A molecules have been...
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