title: Application of asymmetric model in analysis of fluorescence spectra of biologically important molecules.
abstract: Having a valid mathematical model for structureless emission band shapes is important when deconvoluting fluorescence spectra of complex molecules. We propose a new asymmetric model for emission spectra of five organic molecules containing aromatic ring: catechol, coniferyl alcohol, hydroquinone, phenylalanine and tryptophan. For each molecule, a series of emission spectra, varying in excitation wavelength, were fitted with the new model as well as with two other analytical expressions: log-normal, described previously in the literature, and sigmoid-exponential. Their deconvolution into two, three and four Gaussian components was also performed, in order to estimate the number of symmetric components needed to obtain a better fitting quality than that of the asymmetric models. Four subtypes of the new model, as well as the log-normal one, did not differ significantly in their fitting errors, while the sigmoid-exponential model showed a significantly worse fit. Spectra of two mixtures: hydroquinone-coniferyl alcohol and hydroquinone-tryptophan were deconvoluted into two asymmetric and four Gaussian components. Positions of asymmetric components of mixtures matched those of separate molecules, while Gaussian did not. Component analysis of a polymer molecule, lignin, was also performed. In this more complex case asymmetric and Gaussian components also grouped in alternating positions.
authors: Center for Multidisciplinary studies of the University of Belgrade, Despota Stefana, 142 Belgrade, Serbia.
authors: Aleksandar
authors: A
authors: Kalauzi
authors: Dragosav
authors: D
authors: Mutavdzić
authors: Daniela
authors: D
authors: Djikanović
authors: Ksenija
authors: K
authors: Radotić
authors: Milorad
authors: M
authors: Jeremić
mesh_terms: D000465:Algorithms; D001555:Benzene Derivatives / Q000737:chemistry*; D002396:Catechols / Q000737:chemistry; D006873:Hydroquinones / Q000737:chemistry; D008163:Luminescent Measurements / Q000379:methods*; D008962:Models, Theoretical; D010636:Phenols / Q000737:chemistry; D010649:Phenylalanine / Q000737:chemistry; D011336:Probability; D013050:Spectrometry, Fluorescence / Q000379:methods*; D014364:Tryptophan / Q000737:chemistry
chemical_list: D001555:Benzene Derivatives; D002396:Catechols; D006873:Hydroquinones; D010636:Phenols; D010649:Phenylalanine; D014364:Tryptophan; C010559:coniferyl alcohol; C034221:catechol; C031927:hydroquinone