title: Paraquat-loaded alginate/chitosan nanoparticles: preparation, characterization and soil sorption studies.
abstract: Agrochemicals are amongst the contaminants most widely encountered in surface and subterranean hydrological systems. They comprise a variety of molecules, with properties that confer differing degrees of persistence and mobility in the environment, as well as different toxic, carcinogenic, mutagenic and teratogenic potentials, which can affect non-target organisms including man. In this work, alginate/chitosan nanoparticles were prepared as a carrier system for the herbicide paraquat. The preparation and physico-chemical characterization of the nanoparticles was followed by evaluation of zeta potential, pH, size and polydispersion. The techniques employed included transmission electron microscopy, differential scanning calorimetry and Fourier transform infrared spectroscopy. The formulation presented a size distribution of 635 ± 12 nm, polydispersion of 0.518, zeta potential of -22.8 ± 2.3 mV and association efficiency of 74.2%. There were significant differences between the release profiles of free paraquat and the herbicide associated with the alginate/chitosan nanoparticles. Tests showed that soil sorption of paraquat, either free or associated with the nanoparticles, was dependent on the quantity of organic matter present. The results presented in this work show that association of paraquat with alginate/chitosan nanoparticles alters the release profile of the herbicide, as well as its interaction with the soil, indicating that this system could be an effective means of reducing negative impacts caused by paraquat.
authors.affiliation: Department of Environmental Engineering, São Paulo State University - UNESP, Avenida Três de Março, No. 511, CEP 18087-180, Sorocaba, SP, Brazil.
authors.forename: Mariana dos Santos
authors.initials: Mdos S
authors.lastname: Silva
authors.forename: Daniela Sgarbi
authors.initials: DS
authors.lastname: Cocenza
authors.forename: Renato
authors.initials: R
authors.lastname: Grillo
authors.forename: Nathalie Ferreira Silva
authors.initials: NF
authors.lastname: de Melo
authors.forename: Paulo Sérgio
authors.initials: PS
authors.lastname: Tonello
authors.forename: Luciana Camargo
authors.initials: LC
authors.lastname: de Oliveira
authors.forename: Douglas Lopes
authors.initials: DL
authors.lastname: Cassimiro
authors.forename: André Henrique
authors.initials: AH
authors.lastname: Rosa
authors.forename: Leonardo Fernandes
authors.initials: LF
authors.lastname: Fraceto
mesh_terms: D000327:Adsorption; D000464:Alginates; D048271:Chitosan; D004337:Drug Carriers / Q000138:chemical synthesis / Q000737:chemistry*; D020723:Glucuronic Acid; D006540:Herbicides / Q000737:chemistry; D006603:Hexuronic Acids; D053758:Nanoparticles / Q000737:chemistry*; D010269:Paraquat / Q000737:chemistry*; D010316:Particle Size; D012987:Soil / Q000032:analysis / Q000737:chemistry*; D012989:Soil Pollutants
chemical_list: D000464:Alginates; D004337:Drug Carriers; D006540:Herbicides; D006603:Hexuronic Acids; D012987:Soil; D012989:Soil Pollutants; D020723:Glucuronic Acid; D048271:Chitosan; D010269:Paraquat