September 14, 2009
Objective: To separate the components of unsweetened, grape flavored Kool-Aid.
Procedure: Using two syringes, inject different concentrations of alcohol to extract red and blue dyes, and artificial flavoring.
Conclusion: Different dyes are shown when separated by different concentrations of isopropyl alcohol.
Discussion of Theory: Chromatography, resolution and selectivity played major roles in making the experiment work. The experiment demonstrated a common use of chromatography, and works to explain a way to separate mixtures. The dyes were successfully separated and analyzed in the cartridge.
Experimental Sources of Error: We could have produced better results if there was a hands-on instruction before. We had at least four times where the cartridge wasn’t held properly, the syringe was not properly cleaned and even some of the measurements weren’t 100% accurate.
Questions: 1. What is the process of chromatography used for?
Separation of mixtures into the respective parts.
2. In chromatography, components of a mixture distribute themselves between the stationary phase and the mobile phase. Explain how the components can be separated with these two phases.
As the mobile phase solution flows over the stationary phase, the components of the mixture continuously equilibrate between the phases, based of their particular affinity for each phase.
3. In the liquid chromatography column used in this experiment, the solid has a C18 hydrocarbon bonded to it. Would a C18 hydrocarbon be a polar or nonpolar substance? Explain.
C-H bonds are considered very nonpolar. For the chromatography to work, the cartridge would need to be nonpolar.
4. The Kool-Aid that is to be separated in this experiment consists of citric acid, calcium phosphate, salt, maltodextrin, artificial flavor, red #40 and blue #1 dyes. Group these as very polar, moderately polar, or