title: Fiber introduction mass spectrometry: determination of pesticides in herbal infusions using a novel sol-gel PDMS/PVA fiber for solid-phase microextraction.
abstract: An application of the direct coupling of solid-phase microextraction (SPME) with mass spectrometry (MS), a technique known as fiber introduction mass spectrometry (FIMS), is described to determine organochlorine (OCP) and organophosphorus (OPP) pesticides in herbal infusions of Passiflora L. A new fiber coated with a composite of poly(dimethylsiloxane) and poly(vinyl alcohol) (PDMS/PVA) was used. Sensitive, selective, simple and simultaneous quantification of several OCP and OPP was achieved by monitoring diagnostic fragment ions of m/z 266 (chlorothalonil), m/z 195 (alpha-endosulfan), m/z 278 (fenthion), m/z 263 (methyl parathion) and m/z 173 (malathion). Simple headspace SPME extraction (25 min) and fast FIMS detection (less than 40 s) of OCP and OPP from a highly complex herbal matrix provided good linearity with correlation coefficients of 0.991-0.999 for concentrations ranging from 10 to 140 ng ml(-1) of each compound. Good accuracy (80 to 110%), precision (0.6-14.9%) and low limits of detection (0.3-3.9 ng ml(-1)) were also obtained. Even after 400 desorption cycles inside the ionization source of the mass spectrometer, no visible degradation of the novel PDMS/PVA fiber was detected, confirming its suitability for FIMS. Fast (ca 20 s) pesticide desorption occurs for the PDMS/PVA fiber owing to the small thickness of the film and its reduced water sorption.
authors.affiliation: ThoMSon Mass Spectrometry laboratory, Institute of Chemistry, State University of Campinas, 13084-971, Campinas, SP, Brazil.
authors.forename: Rogério Cesar
authors.initials: RC
authors.lastname: da Silva
authors.forename: Vânia Gomes
authors.initials: VG
authors.lastname: Zuin
authors.forename: Janete Harumi
authors.initials: JH
authors.lastname: Yariwake
authors.forename: Marcos Nogueira
authors.initials: MN
authors.lastname: Eberlin
authors.forename: Fabio
authors.initials: F
authors.lastname: Augusto
mesh_terms: D004784:Environmental Monitoring / Q000379:methods; D006801:Humans; D013058:Mass Spectrometry / Q000379:methods*; D008832:Microchemistry / Q000379:methods; D029598:Passiflora / Q000737:chemistry; D010575:Pesticides / Q000032:analysis*; D044367:Phase Transition; D010936:Plant Extracts / Q000737:chemistry; D018515:Plant Leaves / Q000737:chemistry; D015203:Reproducibility of Results; D052617:Solid Phase Microextraction / Q000379:methods*
chemical_list: D010575:Pesticides; D010936:Plant Extracts