title: Immobilization of humic acid in nanostructured layer-by-layer films for sensing applications.
abstract: Humic acids (HAs), naturally occurring biomacromolecules, were incorporated into nanostructured polymeric films using the layer-by-layer (LbL) technique, in which HA layers were alternated with layers of poly(allylamine hydrochloride) (PAH). Atomic force microscopy (AFM) revealed very smooth films, with mean roughness varying from 0.89 to 1.19 nm for films containing 5 and 15 PAH/HA bilayers, respectively. The films displayed electroactivity, with the presence of only one reduction peak at ca. 0.675 V (vs Ag/AgCl). Such a well-defined electroactivity allowed the films to be used as highly sensitive pesticide sensors, with detection of pentachlorophenol (PCP) in solutions at concentrations as low as 10(-9) mol L(-1).
authors.affiliation: IQSC, Universidade de São Paulo, CP, 13560-970, São Carlos, SP, Brazil.
authors.forename: Frank N
authors.initials: FN
authors.lastname: Crespilho
authors.forename: Valtencir
authors.initials: V
authors.lastname: Zucolotto
authors.forename: José R
authors.initials: JR
authors.lastname: Siqueira
authors.forename: Carlos J L
authors.initials: CJ
authors.lastname: Constantino
authors.forename: Francisco C
authors.initials: FC
authors.lastname: Nart
authors.forename: Osvaldo N
authors.initials: ON
authors.lastname: Oliveira
mesh_terms: D015374:Biosensing Techniques; D004563:Electrochemistry; D004784:Environmental Monitoring / Q000379:methods*; D004785:Environmental Pollutants / Q000032:analysis; D006812:Humic Substances; D049329:Nanostructures; D010416:Pentachlorophenol / Q000032:analysis*; D010575:Pesticides / Q000032:analysis*; D011108:Polymers; D012680:Sensitivity and Specificity
chemical_list: D004785:Environmental Pollutants; D006812:Humic Substances; D010575:Pesticides; D011108:Polymers; D010416:Pentachlorophenol