In anion exchange chromatography, the column contains:

• A. hydrophobic groups that bind nonpolar molecules
• B. neutral groups that do not bind ions
• C. negatively charged groups that bind cations
• D. positively charged groups that bind anions

Answer: (D)

Verified step by step guidance

1. Understand the principle of anion exchange chromatography: it separates molecules based on their charge by using a stationary phase that carries positive charges to attract and bind negatively charged ions (anions).
2. Identify the role of the groups on the column: since the goal is to bind anions, the column must have positively charged groups to attract and hold negatively charged species through electrostatic interactions.
3. Evaluate the options given: hydrophobic groups bind nonpolar molecules, neutral groups do not bind ions, negatively charged groups bind cations, so these do not fit the purpose of anion exchange chromatography.
4. Conclude that the correct functional groups on the column are positively charged groups, as they will selectively bind anions during the chromatography process.
5. Summarize that anion exchange chromatography columns contain positively charged groups to effectively separate and retain anions from a mixture.