Chromatography - In-class Problem Set #1
- Page ID
- 72933
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Problem #1
After completing this problem, the student will be able to:
- Draw the idealized plot of the concentration of analyte in the stationary phase versus the concentration in the mobile phase as a function of increasing concentration of analyte injected into the chromatographic system.
- Recognize that in a real situation, the stationary phase will become saturated and the plot will deviate from ideality and exhibit Langmuir behavior
- Predict and justify what the chromatographic peaks will look like for Langmuir and anti-Langmuir behavior
Problem #2
After completing this problem, the student will be able to:
- Realize that a molecule dissolved in a liquid stationary phase moves by the process of diffusion.
Problem #3
After completing this problem, the student will be able to:
- Realize that a molecule dissolved in the mobile phase moves by two processes: (1) diffusion and (2) the physical motion of the flowing mobile phase.
Problem #4
After completing this problem, the student will be able to:
- Realize that starch, silica gel and alumina have hydroxyl groups on their surfaces and are therefore highly polar materials.
- Draw a plot of the distribution of enthalpies of adsorption for a molecule adsorbing onto silanol, disilanol and trisilanol groups.
- Recognize that the overall enthalpy of adsorption is the sum of the individual plots.
- Describe why the distribution of the enthalpy of adsorption is not symmetric.
- Predict the shape of the peak that would result for such a distribution of the enthalpy of adsorption and explain why this is not a favorable situation for chromatographic efficiency.