1. Normal Phase Chromatography Column material is _______ (silica/bonded phase)
ID: 542971 • Letter: 1
Question
1. Normal Phase Chromatography Column material is _______ (silica/bonded phase) Column material is _______ (polar/non-polar) Elution begins with _______ (polar/non-polar) solvent and ends with _______ (polar/non-polar) solvent
2. Reverse Phase Chromatography **Column material is _______ (silica/bonded phase) Column material is _______ (polar/non-polar) Elution begins with _______ (polar/non-polar) solvent and ends with ______ (polar/non-polar) solvent
3. (Make sure you discuss both parts and write clearly and completely your explanation.) In normal phase chromatography a low or less polar organic solvent is initially equilibrated on the column. The sample is added to the column and elution begins. A more polar solvent is slowly added to the original solvent to elute the sample components. In this situation the eluent strength is said to increase as the solvent system becomes more polar because the components are eluted from the column. In reversed-phase chromatography a high or more polar organic solvent is initially equilibrated on the column. The sample is added to the column and elution begins. A less polar solvent is slowly added to the original solvent to elute the sample components. In this situation the eluent strength is said to increase as the solvent system becomes less polar because the components are eluted from the column. Explain why the eluent strength is said to increase in both cases but the solvent polarity is actually going in opposite directions in the two chromatography modes.
Explanation / Answer
1. Normal Phase Chromatography Column material is silica Column material is polar Elution begins with non-polar solvent and ends with polar solvent.
2. Reverse Phase Chromatography Column material is bonded phase (C8 and C18 are very common) Column material is non-polar Elution begins with polar solvent and ends with non-polar solvent
Related Questions
Navigate
Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.