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: ThoMSon Mass Spectrometry laboratory, Institute of Chemistry, State University of Campinas, 13084-971 Campinas, SP, Brazil.
authors: Rogério Cesar
authors: RC
authors: da Silva
authors: Vânia Gomes
authors: VG
authors: Zuin
authors: Janete Harumi
authors: JH
authors: Yariwake
authors: Marcos Nogueira
authors: MN
authors: Eberlin
authors: Fabio
authors: F
authors: Augusto
mesh_terms: D004129:Dimethylpolysiloxanes; D004340:Drug Contamination; D006843:Hydrocarbons, Chlorinated / Q000032:analysis; D013058:Mass Spectrometry / Q000379:methods*; D009943:Organophosphorus Compounds / Q000032:analysis; D029598:Passiflora / Q000737:chemistry; D010575:Pesticides / Q000032:analysis*; D010936:Plant Extracts / Q000032:analysis*; D011142:Polyvinyl Alcohol; D052617:Solid Phase Microextraction / Q000379:methods*
chemical_list: D004129:Dimethylpolysiloxanes; D006843:Hydrocarbons, Chlorinated; D009943:Organophosphorus Compounds; D010575:Pesticides; D010936:Plant Extracts; D011142:Polyvinyl Alcohol