Title: fronting
Long Title: IUPAC Gold Book - fronting
DOI: 10.1351/goldbook.F02534
Status: current

Definition
Asymmetry of a peak such that, relative to the baseline, the front is less steep than the rear. In paper chromatography and thin-layer chromatography, it refers to the distortion of a spot showing a diffuse region in front of the spot in the direction of flow.

Related Terms
- Asymmetry: https://goldbook.iupac.org//terms/view/A00486
- chromatography: https://goldbook.iupac.org//terms/view/C01075
- thin-layer chromatography: https://goldbook.iupac.org//terms/view/T06346

Sources
- Orange Book, 2nd ed., p. 96 (https://media.iupac.org/publications/analytical_compendium/)
- PAC, 1993, 65, 819. 'Nomenclature for chromatography (IUPAC Recommendations 1993)' on page 837 (https://doi.org/10.1351/pac199365040819)

Other Outputs
- html: https://goldbook.iupac.org/terms/view/F02534/html
- json: https://goldbook.iupac.org/terms/view/F02534/json
- xml: https://goldbook.iupac.org/terms/view/F02534/xml

Citation: Citation: 'fronting' 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.F02534
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Disclaimer: The International Union of Pure and Applied Chemistry (IUPAC) is continuously reviewing and, where needed, updating terms in the Compendium of Chemical Terminology (the IUPAC Gold Book). Users of these terms are encouraged to include the version of a term with its use and to check regularly for updates to term definitions that you are using.
Accessed: 2026-05-01T09:53:31+00:00