Chromatography I - Fundamentals (Worksheet)
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Work in groups on these problems. You should try to answer the questions without referring to your textbook. If you get stuck, try asking another group for help.
- Consider a plot that has the concentration of analyte in the stationary phase on the Y-axis and the concentration of analyte in the mobile phase on the X-axis.
- Draw an idealized plot as greater concentrations of analyte are injected into the chromatographic column.
- Draw what you suspect would really happen.
- What might the peaks look like in the real versus ideal situations?
- What term would we use to describe the movement of a molecule in a liquid stationary phase?
- What processes would account for the movement of a molecule through a region of interstitial volume in a mobile phase?
- Tswett used starch as his stationary phase.
- What is the dominant surface functionality of starch?
- The two other common solid stationary phases are silica gel (SiO2) and alumina (Al2O3).What do you think are the surface functionalities of these materials?
- Draw a plot of the distribution of enthalpies of adsorption for a molecule on the surface of starch, silica gel, or alumina.
- What would a chromatographic peak look like on such a phase with such a plot of adsorption enthalpies?
- What is the problem with your peak?