Multiple Choice
What is the order of elution (first → last) of the following amino acids in reverse-phase HPLC: Ala, Arg, Leu.
5. Protein Techniques
HPLC
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Join thousands of students who trust us to help them ace their exams!Watch the first videoMultiple Choice
What is the order of elution (first → last) of the following amino acids in normal-phase HPLC: Phe, Gly, Glu.
A
Phe → Gly → Glu.
B
Phe → Glu → Gly.
C
Glu → Phe → Gly.
D
Glu → Gly → Phe.
E
Gly → Phe → Glu.
F
Gly → Glu → Phe.
Verified step by step guidance1
Understand the principle of normal-phase HPLC, which separates compounds based on polarity. In normal-phase HPLC, the stationary phase is polar, and the mobile phase is non-polar.
Identify the polarity of each amino acid. Phenylalanine (Phe) is non-polar due to its aromatic side chain, Glycine (Gly) is slightly polar, and Glutamic acid (Glu) is polar due to its acidic side chain.
Recall that in normal-phase HPLC, non-polar compounds elute first because they interact less with the polar stationary phase.
Determine the order of elution based on polarity: the least polar amino acid will elute first, followed by the more polar ones.
Arrange the amino acids in order of increasing polarity: Phe (least polar) → Gly → Glu (most polar).
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