Virtual lab: chromatography [30 points; 5 points / question in purple]

 

This virtual laboratory activity is based on the handout to the corresponding in-person lab activity,

 

background

1. brief description on the applications of chromatography

2. using the concept of IMF, describe the basis of adsorption chromatography; include / define the terms "stationary-" & "mobile-" phase in your response. hints: while the animations: chromatographic separation (video; ~ 6"); stationary phase (video; ~3:25); eluation (video; ~ 4" ) describes a normal phase (i.e. polar) stationary phase, where this lab uses a reverse phase stationary phase, the concepts are similar in both types of stationary phases, i.e. both involves IMF. exploring the simulation may provide an insight into the process, where you can ignore the solvent molecules in the stationary phase - to keep it simple.

3. MSDS data on isopropyl alcohol

 methods / results / discussion.  clearly identify the various molecules in the system:  blue dye, red dye, alcohol, and stationary phase molecule - in your response.  hints:   the chemical structures of the various chemicals in the lab & another type of IMF not described in class may help to address the below questions. 

4.   based on the below links, describe the experimental procedure & results in the videos:

     video 1 (use nonpolar stationary phase; 5:38)

     video 2 (use polar stationary phase; 5:35)

5.  based on concepts involving IMF, what is the basis / rationale of the preceding observations in one of the preceding videos (identify the video) ?

     in regards to the nonpolar column (for video 1), 

          why only one dye came out ? 

          why the other dye came out of the column after changing the amount of alcohol ?

      in regards to the polar column (for video 2),

            why did both dyes come out of the column separately ?

6.  unlike the results in the preceding videos, which used either water or 5% alcohol, using 15% alcohol and a nonpolar stationary phase produced a separation of the red dye followed by the blue dye.  on the other hand, using 70% alcohol, both dyes came out of the nonpolar columm together.  based on concepts involving IMF, rationalize these observations.