title: Dispersive liquid-liquid microextraction of organophosphorous pesticides using nonhalogenated solvents.
abstract: Dispersive liquid-liquid microextraction (DLLME) combined with gas chromatography and mass spectrometry (GC-MS) was applied to the determination of five organophosphorous pesticides (OPPs) in water samples. The analytes included in this study were prophos, diazinon, chlorpyrifos methyl, fenchlorphos, and chlorpyrifos. The use of nonhalogenated solvents (cyclohexane, heptane, and octane) as extraction solvents was investigated using acetone, acetonitrile, or methanol, as dispersion solvents. The combination of less polar dispersion solvents (1-propanol and 2-propanol) and nonhalogenated extraction solvents was also studied in dispersive liquid-liquid microextraction for the first time. Several experimental conditions were tested (nature and volume of extraction solvents, nature and volume of dispersion solvents, salting-out effect) and the corresponding enrichment factors and recoveries were evaluated. The best microextraction condition was obtained using 50 μL of cyclohexane and 0.3 mL of 1-propanol. The detection and quantification limits were in the low ppt range, with values between 3.3-8.0 ng/L and 11.0-26.6 ng/L, respectively. Relative standard deviations were between 6.6 and 13.1% for a fortification level of 500 ng/L. At the same fortification level, the relative recoveries (RR) of Alvito's dam water, Judeu's river water, and well water samples were in the range of 50.3-97.1%.
authors: Departamento de Ciências e Tecnologia da Biomassa, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, Caparica, Portugal. acha@campus.fct.unl.pt
authors: Andreia Cristina Henriques
authors: AC
authors: Alves
authors: Maria Margarida Pontes Boavida
authors: MM
authors: Gonçalves
authors: Maria Manuel Serrano
authors: MM
authors: Bernardo
authors: Benilde Simões
authors: BS
authors: Mendes
mesh_terms: D008401:Gas Chromatography-Mass Spectrometry; D059627:Liquid Phase Microextraction / Q000379:methods*; D009943:Organophosphorus Compounds / Q000032:analysis / Q000302:isolation & purification*; D010575:Pesticides / Q000032:analysis / Q000302:isolation & purification*; D012997:Solvents / Q000737:chemistry; D014874:Water Pollutants, Chemical / Q000032:analysis / Q000302:isolation & purification*
chemical_list: D009943:Organophosphorus Compounds; D010575:Pesticides; D012997:Solvents; D014874:Water Pollutants, Chemical