title: Peptide-based affinity media for solid-phase extraction of Ochratoxin A from wine samples: Effect of the solid support on binding properties.
abstract: A suitable sample clean up is a key point in the development of an analytical method. Peptide-based affinity media have recently gained attention in the selective extraction of defined target analytes from complex samples. In this paper we investigated the thermodynamic and kinetic binding properties of different stationary phases (Amberlite IRC-50, Lewatit CNP105, Toyopearl CM-650 M, porous silica gel beads and micrometric glass beads) functionalized with a hexapeptide sequence binding the Ochratoxin A. The highest values of the equilibrium binding constant (Keq) and binding site concentration (Bmax) were obtained for Lewatit CNP105 (Keq: 98.1×10(6) M(-1), Bmax: 30.8 μmol/g), followed by Toyopearl and micrometric glass beads, whereas the worst performances were obtained with Amberlite IRC-50 and porous silica gel beads. Also kinetic performances show the same trend. These results highlight that the surface chemical nature has a key role in the binding properties of solid supports used as affinity media for the selective extraction of well-defined target molecules. Finally, Lewatit CNP105 was compared with Amberlite IRC-50 as solid support in SPE extraction of OTA from 14 wine samples fortified with OTA at 2 and 4 μg l(-1) levels. The extracts were analyzed by HPLC with fluorescence detection (λexc 333 nm, λem 460 nm) showing no significant matrix effects, with a LOD and LOQ of 0.45 and 1.5 μgl(-1), respectively, and good recoveries between 71% and 108% for Amberlite IRC-50 and 91% and 101% for Lewatit CNP105. While both supports showed a statistically comparable extraction accuracy, a statistically significant difference was found in terms of extraction precision, confirming that the solid phase based on Lewatit CNP105 performs better than the solid phase based on Amberlite IRC-50.
authors.affiliation: Department of Chemistry, Via Giuria 7, University of Torino, Torino, Italy. Electronic address: cristina.giovannoli@unito.it.
authors.forename: Cristina
authors.initials: C
authors.lastname: Giovannoli
authors.affiliation: Department of Chemistry, Via Giuria 7, University of Torino, Torino, Italy.
authors.forename: Cinzia
authors.initials: C
authors.lastname: Passini
authors.affiliation: Department of Chemistry, Via Giuria 7, University of Torino, Torino, Italy.
authors.forename: Giorgio
authors.initials: G
authors.lastname: Volpi
authors.affiliation: Department of Chemistry, Via Giuria 7, University of Torino, Torino, Italy.
authors.forename: Fabio
authors.initials: F
authors.lastname: Di Nardo
authors.affiliation: Department of Chemistry, Via Giuria 7, University of Torino, Torino, Italy.
authors.forename: Laura
authors.initials: L
authors.lastname: Anfossi
authors.affiliation: Department of Chemistry, Via Giuria 7, University of Torino, Torino, Italy.
authors.forename: Claudio
authors.initials: C
authors.lastname: Baggiani
mesh_terms: D002851:Chromatography, High Pressure Liquid; D005506:Food Contamination / Q000032:analysis*; D005898:Glass / Q000737:chemistry; D009793:Ochratoxins / Q000032:analysis* / Q000737:chemistry; D009842:Oligopeptides / Q000737:chemistry*; D011108:Polymers / Q000737:chemistry; D012117:Resins, Synthetic / Q000737:chemistry; D058428:Silica Gel / Q000737:chemistry; D052616:Solid Phase Extraction; D014920:Wine / Q000032:analysis*
chemical_list: D009793:Ochratoxins; D009842:Oligopeptides; D011108:Polymers; D012117:Resins, Synthetic; C025589:ochratoxin A; D058428:Silica Gel; C058606:Toyopearl 650; C024946:Amberlite IRC50
keywords: Affinity chromatography; Binding peptide; Binding properties; Ochratoxin A; Solid-phase extraction; Wine analysis