title: Determination of organophosphorous pesticides in the ppq range using a simple solid-phase extraction method combined with dispersive liquid-liquid microextraction.
abstract: Solid-phase extraction combined with dispersive liquid-liquid microextraction (SPE-DLLME) was applied for the extraction of six organophosphorous pesticides (OPPs) in water samples. The analytes considered in this study were determined by gas chromatography with mass spectrometry and included prophos, diazinon, chlorpyrifos methyl, methyl parathion, fenchlorphos and chlorpyrifos. Several extraction conditions (extraction solvent and elution/dispersion solvents nature, extraction solvent volume, elution solvent volume, water volume and sample volume) were tested for SPE-DLLME with these analytes and the best results were obtained using carbon tetrachloride as the extraction solvent and acetone as the elution/dispersion solvent. Calibration curves for the determination of OPPs in water samples were constructed in the concentration range of 10-100 ng/L. Limits of detection (LODs) ranged from 38 to 230 pg/L values that are below the maximum admissible level for drinking water (100 ng/L). Relative standard deviations (RSD) were between 8.6 and 10.4% for a fortification level of 100 ng/L. At the same fortification level, the relative recoveries (R.R.) of tap, well and irrigation water samples were in the range of 30.2-97.1%.
authors.affiliation: Departamento de Ciências e Tecnologia da Biomassa, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, Caparica, Portugal. acha@fct.unl.pt
authors.forename: Andreia Cristina Henriques
authors.initials: AC
authors.lastname: Alves
authors.forename: Maria Margarida Pontes Boavida
authors.initials: MM
authors.lastname: Gonçalves
authors.forename: Maria Manuel Serrano
authors.initials: MM
authors.lastname: Bernardo
authors.forename: Benilde Simões
authors.initials: BS
authors.lastname: Mendes
mesh_terms: D008401:Gas Chromatography-Mass Spectrometry; D059627:Liquid Phase Microextraction; D009943:Organophosphorus Compounds / Q000032:analysis*; D010575:Pesticides / Q000032:analysis*; D052616:Solid Phase Extraction; D014874:Water Pollutants, Chemical / Q000737:chemistry*
chemical_list: D009943:Organophosphorus Compounds; D010575:Pesticides; D014874:Water Pollutants, Chemical