title: Binding interactions between suberin monomer components and pesticides.
abstract: Understanding the role of biomacromolecules and their interactions with pollutants is a key for elucidating the sorption mechanisms and making an accurate assessment of the environmental fate of pollutants. The knowledge of the sorption properties of the different constituents of these biomacromolecules may furnish a significant contribution to this purpose. Suberin is a very abundant biopolymer in higher plants. In this study, suberin monomers isolated from cork were analyzed by thermally-assisted methylation with tetramethylammonium hydroxide (TMAH) in a pyrolysis unit coupled to gas chromatography-mass spectrometry (GC/MS). The isolated monomer mixture was used to study the sorption of three pesticides (isoproturon, methomyl and oxamyl). The modes of pesticide-sorbent interactions were analyzed by means of two modeling calculations, the first one representing only the mixture of suberin monomers used in the sorption study, and the second one including glycerol to the mixture of suberin monomers, as a building block of the suberin molecule. The results indicated that the highest sorption capacity exhibited by the sorbent was for isoproturon (33%) being methomyl and oxamyl sorbed by the main suberin components to a lesser extent (3% and<1%, respectively). In addition to van der Waals interactions with the apolar region of sorbent and isoproturon, modeling calculations evidenced the formation of a hydrogen bond between the isoproturon NH group and a carboxylic oxygen atom of a suberin monomer. In the case of methomyl and oxamyl only weak van der Waals interactions stabilize the pesticide-sorbent adducts. The presence of glycerol in the model provoked significant changes in the interactions with isoproturon and methomyl.
authors.affiliation: Department of Chemical Engineering, Escola Politècnica Superior, Universitat de Girona, Maria Aurèlia Capmany, 61, 17071 Girona, Spain. Electronic address: angels.olivella@udg.edu.
authors.forename: M À
authors.initials: MÀ
authors.lastname: Olivella
authors.affiliation: Department of Chemistry "Ugo Schiff", University of Florence, Via della Lastruccia, 3, 50019 Sesto Fiorentino, Italy.
authors.forename: C
authors.initials: C
authors.lastname: Bazzicalupi
authors.affiliation: Department of Chemistry "Ugo Schiff", University of Florence, Via della Lastruccia, 3, 50019 Sesto Fiorentino, Italy.
authors.forename: A
authors.initials: A
authors.lastname: Bianchi
authors.affiliation: Instituto de Recursos Naturales y Agrobiología de Sevilla, Consejo Superior de Investigaciones Científicas, P.O. Box 1052, 41080 Seville, Spain.
authors.forename: J C
authors.initials: JC
authors.lastname: del Río
authors.affiliation: Department of Chemical Engineering, Escola Politècnica Superior, Universitat de Girona, Maria Aurèlia Capmany, 61, 17071 Girona, Spain.
authors.forename: N
authors.initials: N
authors.lastname: Fiol
authors.affiliation: Department of Chemical Engineering, Escola Politècnica Superior, Universitat de Girona, Maria Aurèlia Capmany, 61, 17071 Girona, Spain.
authors.forename: I
authors.initials: I
authors.lastname: Villaescusa
mesh_terms: D008401:Gas Chromatography-Mass Spectrometry; D008055:Lipids / Q000737:chemistry*; D008956:Models, Chemical; D010575:Pesticides / Q000737:chemistry*
chemical_list: D008055:Lipids; D010575:Pesticides; C065875:suberin
keywords: Glycerol; Isoproturon; Methomyl; Molecular modeling; Oxamyl; Suberin; Van der Waals