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.
PAC, 1993, 65, 819
(Nomenclature for chromatography (IUPAC Recommendations 1993))
on page 837
IUPAC. Compendium of Chemical Terminology, 2nd ed. (the "Gold Book"). Compiled by A. D. McNaught and A. Wilkinson. Blackwell Scientific Publications, Oxford (1997). XML on-line corrected version: http://goldbook.iupac.org (2006-) created by M. Nic, J. Jirat, B. Kosata; updates compiled by A. Jenkins. ISBN 0-9678550-9-8. doi:10.1351/goldbook