title: Continuous flow configuration for total hydrocarbons index determination in soils by evaporative light scattering detection.
abstract: A continuous flow configuration is proposed for the estimation of the hydrocarbon index in soils using for the first time evaporative light scattering detection (ELSD). The method is based on a membrane-enrichment of the hydrocarbons of interest (C10-C40), which are previously extracted from the soil matrix with a water:hexane mixture using a household microwave oven. The organic supernatant is cleaned-up through silica, evaporated and redissolved in a sodium dodecyl sulphate aqueous solution which is introduced in the loop of an injection valve. The sample, carried by an aqueous stream, passes through a continuous filtration unit fitted with a 1 microm pore size PTFE membrane, where the hydrocarbons are retained while the potential coextracted compounds are wasted. Quantitative elution of the C10-C40 fraction is accomplished by passing an acetone stream through the filter which drives the analytes to the ELSD system for analytical measurement. The detection limit was 1.8 microg ml(-1), the linear range 5-25 microg ml(-1) and the precision 4.3%. The recoveries were between 93 and 97%. The proposed method was also evaluated by attenuated total reflexion-Fourier transform (ATR-FT-IR) analysis of the extracts.
authors.affiliation: Department of Analytical Chemistry, Campus de Rabanales, University of Córdoba, E-14071 Córdoba, Spain.
authors.forename: Eva
authors.initials: E
authors.lastname: Aguilera-Herrador
authors.forename: Rafael
authors.initials: R
authors.lastname: Lucena
authors.forename: Soledad
authors.initials: S
authors.lastname: Cárdenas
authors.forename: Miguel
authors.initials: M
authors.lastname: Valcárcel
mesh_terms: D002138:Calibration; D006838:Hydrocarbons / Q000032:analysis*; D008027:Light; D012542:Scattering, Radiation; D012989:Soil Pollutants / Q000032:analysis*; D017550:Spectroscopy, Fourier Transform Infrared
chemical_list: D006838:Hydrocarbons; D012989:Soil Pollutants