Title: asymmetry factor
Long Title: IUPAC Gold Book - asymmetry factor
DOI: 10.1351/goldbook.09902
Status: current

Definition
Width of a peak (\(f + b\)) divided by twice the width of the front of the peak (\(f\)), measured at \(\pu{10\%}\) of the peak height (see figure). \[A_{\rm{s}} = \frac{(f + b)}{2f}\] Peak asymmetry (schematic). \(R_{\rm{D}}\) is the response of the detector.Peak asymmetry (schematic). \(R_{\rm{D}}\) is the response of the detector.

Notes
1) For a symmetrical peak \(A_{\rm{s}} = 1\).
2) Some pharmacopoeia definitions of peak asymmetry measure the value at \(\pu{5\%}\) of the peak height.

Related Term
- tailing factor: https://goldbook.iupac.org//terms/view/09905

Source
- PAC, 2017, 90, 181. 'Terminology of separation methods (IUPAC Recommendations 2017)' on page 193 (https://doi.org/10.1515/pac-2017-0111)

Other Outputs
- html: https://goldbook.iupac.org/terms/view/09902/html
- json: https://goldbook.iupac.org/terms/view/09902/json
- xml: https://goldbook.iupac.org/terms/view/09902/xml

Citation: Citation: 'asymmetry factor' in IUPAC Compendium of Chemical Terminology, 5th ed. International Union of Pure and Applied Chemistry; 2025. Online version 5.0.0, 2025. 10.1351/goldbook.09902
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Accessed: 2026-06-28T14:36:15+00:00