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A procedure for analysis of densitometric spectra
Author(s) -
Galat Andrzej
Publication year - 1989
Publication title -
electrophoresis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.666
H-Index - 158
eISSN - 1522-2683
pISSN - 0173-0835
DOI - 10.1002/elps.1150101002
Subject(s) - spectral line , cauchy distribution , asymmetry , densitometry , gauss , chemistry , analytical chemistry (journal) , mathematics , mathematical analysis , chromatography , physics , optics , quantum mechanics , astronomy
Computer‐aided quantitative analysis of densitometric spectra is presented. The densitometric spectra are decomposed into component bands using the Powell and Marquardt minimizers. Several different functions for the component bands are utilized. It is shown that the densitometric spectra can be decomposed into component bands with high accuracy only if the proper shapes of the bands are chosen. The method described was used for quantitative analysis of densitometric spectra of DNA cleaved by neocarzinostatin. The procedure is general and can be applied to analyses of autoradiographic films and to direct scans of electrophoretic gels. It is shown that densitometric spectra which show highly overlapped bands are well approximated by asymmetric Cauchy and Gauss functions. Well separated densitometric bands which have substantial asymmetry can be fitted to more sophisticated shapes formed by combinations of symmetric and asymmetric Cauchy and Gauss functions. High accuracy fitting to asymmetric densitometric curves may only be achieved using the cosine function introduced by Mignot and Rondot, J. Appl. Cryst. 1976, 9 , 460–465.