Chromatographic retention, resolution and efficiency
Retention factor measures time spent beyond an unretained marker relative to its transit time.
Key knowledge
Retention factor measures time spent beyond an unretained marker relative to its transit time. Two-peak resolution compares retention-time separation with peak widths. Theoretical plate counts describe band broadening under a peak-shape model; a plate is an analytical construct, not a physical layer of the column.
Values and equations
k′ = (tR−tM)/tM; Rs = 2(tR,2−tR,1)/(w1+w2); N = 16(tR/w)²
- k′
- retention factor 1
- tR,tR,1,tR,2
- retention times s
- tM
- unretained marker transit time s
- Rs
- baseline-width resolution 1
- w,w1,w2
- baseline peak widths s
- N
- theoretical plate count for the stated peak 1
Conditions and scope
- Use the stated baseline-width convention and approximately Gaussian isolated peaks for the displayed plate formula.
- Metrics depend on analyte and operating conditions; a single retention time does not prove identity.
Sources · 1
References
Sources retain their recorded scope. A source link alone does not establish verification of every statement.
Evidence and review
Inspected retention-factor, baseline resolution and Gaussian plate-count sections/equations.
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Entry details
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