Difficulty: Medium
Correct Answer: Both partition chromatography and electrical mobility of ionic species
Explanation:
Introduction / Context:
Some analytical methods intentionally blend mechanisms to increase resolution. Coupling paper chromatography (partition-based) with electrophoresis (field-driven migration) is a classic example used for amino acids, peptides, and small metabolites.
Given Data / Assumptions:
Concept / Approach:
Paper chromatography relies on partitioning between water held in cellulose fibers (stationary) and a moving organic/aqueous solvent (mobile). Electrophoresis adds a second dimension: separation by electrophoretic mobility, which depends on charge and size in the buffer.
Step-by-Step Solution:
Identify partition component: distribution between immobilized water and mobile phase.Identify electrophoresis component: migration under electric field based on net charge.Select the option acknowledging both mechanisms.
Verification / Alternative check:
Two-dimensional separations (first electrophoresis, then chromatography, or vice versa) produce orthogonal patterns consistent with the two distinct principles.
Why Other Options Are Wrong:
Option a ignores the electrophoretic contribution.Option b ignores the chromatographic partitioning.Option d is wrong because a combined mechanism is indeed correct.
Common Pitfalls:
Assuming a single mechanism explains complex separations; overlooking the impact of pH on electrophoretic mobility.
Final Answer:
Both partition chromatography and electrical mobility of ionic species.
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