HPLC technique families: Which set correctly lists the major high-performance liquid chromatography modes commonly used in laboratories?
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Aliquid/liquid (partition) chromatography
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Bliquid/solid (adsorption) chromatography
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Cion exchange and size exclusion chromatography
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Dall of the above
Answer
Correct Answer: all of the above
Explanation
Introduction / Context:HPLC is not one technique but a platform supporting multiple separation mechanisms. Knowing the main HPLC modes guides analysts in matching chemistry to the problem: polarity differences, charge, or size.
Given Data / Assumptions:
- Partition (liquid/liquid, now typically liquid–stationary bonded phase) separates by differential partitioning.
- Adsorption (liquid/solid, e.g., normal-phase on silica) separates by surface interactions.
- Ion-exchange separates by electrostatic interactions; size exclusion (gel permeation) separates by hydrodynamic volume.
Concept / Approach:HPLC modes correspond to analyte–stationary phase interaction types. Reversed-phase (a partition variant) dominates for small molecules, ion-exchange suits ionic biomolecules, and size exclusion is preferred for polymers and proteins where minimal interaction is desired.
Step-by-Step Solution:Enumerate common modes: partition, adsorption, ion-exchange, and size-exclusion.Confirm each option names a legitimate HPLC mode.Choose the comprehensive option listing all.
Verification / Alternative check:Method compendia (e.g., pharmacopeias) and HPLC vendor manuals organize columns and applications by precisely these modes.
Why Other Options Are Wrong:
- Options (a), (b), (c) are subsets; none alone is exhaustive.
Common Pitfalls:Equating reversed-phase only with HPLC; while dominant, it is one of several modes.
Final Answer:all of the above