title: Hollow-fiber liquid-phase microextraction for the determination of pesticides and metabolites in soils and water samples using HPLC and fluorescence detection.
abstract: A new and simple method has been developed for the determination of a group of four benzimidazole pesticides (carbendazim/benomyl, thiabendazole, and fuberidazole), a carbamate (carbaryl), and an organophosphate (triazophos), together with two of their main metabolites (2-aminobenzimidazole, metabolite of carbendazim/benomyl, and 1-naphthol, metabolite of carbaryl) in soils. First, an ultrasound-assisted extraction (UAE) was performed, followed by evaporation and reconstitution in water. Then, extraction and preconcentration of the analytes was accomplished by two-phase hollow-fiber liquid-phase microextraction (HF-LPME) using 1-octanol as extraction solvent. Parameters that affect the extraction efficiency in HF-LPME technique (organic solvent, pH of the sample, extraction time, stirring speed, temperature, and ionic strength) were deeply investigated. Optimum HF-LPME conditions involved the use of a 2.0 cm polypropylene fiber filled with 1-octanol to extract 10 mL of an aqueous soil extract at pH 9.0 containing 20% (v/v) of NaCl for 30 min at 1440 rpm. Separation and quantification was achieved by HPLC with fluorescence detection (FD). The proposed optimum UAE-HF-LPME-HPLC-FD methodology provided good calibration, precision, and accuracy results for two soils of different physicochemical properties. LODs were in the range 0.001-6.94 ng/g (S/N = 3). With the aim of extending the validation, the HF-LPME method was also applied to different types of waters (Milli-Q, mineral and run-off), obtaining LODs in the range 0.0002-0.57 μg/L.
authors: Departamento de Química Analítica, Nutrición y Bromatología, Facultad de Química, Universidad de La Laguna-ULL, La Laguna-Tenerife, España.
authors: María
authors: M
authors: Asensio-Ramos
authors: Javier
authors: J
authors: Hernández-Borges
authors: Guillermo
authors: G
authors: González-Hernández
authors: Miguel Ángel
authors: MÁ
authors: Rodríguez-Delgado
mesh_terms: D020003:1-Octanol / Q000737:chemistry; D001562:Benzimidazoles / Q000302:isolation & purification* / Q000378:metabolism; D002851:Chromatography, High Pressure Liquid / Q000379:methods; D057230:Limit of Detection; D059627:Liquid Phase Microextraction / Q000379:methods*; D010575:Pesticides / Q000302:isolation & purification* / Q000378:metabolism; D012987:Soil / Q000032:analysis; D012989:Soil Pollutants / Q000302:isolation & purification* / Q000378:metabolism; D014867:Water / Q000032:analysis; D014874:Water Pollutants, Chemical / Q000302:isolation & purification* / Q000378:metabolism
chemical_list: D001562:Benzimidazoles; D010575:Pesticides; D012987:Soil; D012989:Soil Pollutants; D014874:Water Pollutants, Chemical; D014867:Water; D020003:1-Octanol