If the classification of the chromatography run is a reverse-phase chromatography, discuss the relative polarities of caffeine, aspartame and benzoate.

How could you prepare a sample of pure (S)-naproxen from a sample of racemic naproxen using chromatography?

Please propose a chromatography-based strategy to purify human insulin proteins that have been expressed in bacterial cells.

The compounds biphenyl and naphthalene are presented in a mixture. Can hexane be used as a solvent to separate the compounds by column chromatography with silica gel as the stationary phase? Why or why not.

You run the chromatography system with paper as the stationary phase and 70% isopropanol as the mobile phase. You determine the Rf  of a polar analyte to be 0.40. If you use 100% isopropanol (a less polar solvent) instead of isopropanol as the mobile phase what would you expect to happen to the Rf  value? No value effect on Rf higher  lower could be higher or lower

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Identify the mobile and stationary phases in thin layer chromatography(TLC) and explain how the separation is carried out in (TLC). [

Compare the principles of sugar separation using paper chromatography and high performance chromatography (HPLC), in terms of their similarities and differences. (E.g.: Mobile phase, Stationary phase, column) conclude.

When a mixture of three compounds ( is purified by column chromatography using different concentrations of solvents, the following is observed. 1) 50 ml 100 % Hexane-compound 1 elutes 2) 50 ml 20: 80 ether: hexane- compound 2 elutes 3) 100 % ether- compound 3 elutes based on the observations above, choose all the correct statements O compound 3 retains least on the column and is the least polar. O compound 2 is most likely a hydroxyl compound( 2 naphthol) and is somewhat polar O compound 1 retains longest on the column. and is the most polar O compound 1 is most likely a neutral compound (e.g. naphthalene), and is almost non polar O compound 3 is most likely a carboxylic acid like compound ( benzoic acid), and is very polar O compound 2 retains on the column more than 1 but less than 3 because it is a neutral compound.