title: Salting-out assisted liquid-liquid extraction and partial least squares regression to assay low molecular weight polycyclic aromatic hydrocarbons leached from soils and sediments.
abstract: A novel method was developed to determine low molecular weight polycyclic aromatic hydrocarbons in aqueous leachates from soils and sediments using a salting-out assisted liquid-liquid extraction, synchronous fluorescence spectrometry and a multivariate calibration technique. Several experimental parameters were controlled and the optimum conditions were: sodium carbonate as the salting-out agent at concentration of 2molL-1, 3mL of acetonitrile as extraction solvent, 6mL of aqueous leachate, vortexing for 5min and centrifuging at 4000rpm for 5min. The partial least squares calibration was optimized to the lowest values of root mean squared error and five latent variables were chosen for each of the targeted compounds. The regression coefficients for the true versus predicted concentrations were higher than 0.99. Figures of merit for the multivariate method were calculated, namely sensitivity, multivariate detection limit and multivariate quantification limit. The selectivity was also evaluated and other polycyclic aromatic hydrocarbons did not interfere in the analysis. Likewise, high performance liquid chromatography was used as a comparative methodology, and the regression analysis between the methods showed no statistical difference (t-test). The proposed methodology was applied to soils and sediments of a Brazilian river and the recoveries ranged from 74.3% to 105.8%. Overall, the proposed methodology was suitable for the targeted compounds, showing that the extraction method can be applied to spectrofluorometric analysis and that the multivariate calibration is also suitable for these compounds in leachates from real samples.
authors: Departamento de Química, Universidade Federal de Santa Maria, 97111-900 Santa Maria, RS, Brazil.
authors: Lucas P
authors: LP
authors: Bressan
authors: Departamento de Química, Universidade Federal de Santa Maria, 97111-900 Santa Maria, RS, Brazil. Electronic address: pcn1954@gmail.com.
authors: Paulo Cícero
authors: PC
authors: do Nascimento
authors: Departamento de Química, Universidade Federal de Santa Maria, 97111-900 Santa Maria, RS, Brazil.
authors: Marcella E P
authors: MEP
authors: Schmidt
authors: Departamento de Química, Universidade Federal de Santa Maria, 97111-900 Santa Maria, RS, Brazil.
authors: Henrique
authors: H
authors: Faccin
authors: Departamento de Química, Universidade Federal de Santa Maria, 97111-900 Santa Maria, RS, Brazil.
authors: Leandro Carvalho
authors: LC
authors: de Machado
authors: Departamento de Química, Universidade Federal de Santa Maria, 97111-900 Santa Maria, RS, Brazil.
authors: Denise
authors: D
authors: Bohrer
keywords: Aqueous leachates; Multivariate calibration; Partial least squares; Polycyclic aromatic hydrocarbons; Salting-out assisted liquid-liquid extraction; Synchronous fluorescence