Study of the Effects of Environmental Variables and Supercritical Fluid Extraction Parameters on the Extractability of Pesticide Residues from Soils Using a Multivariate Optimization Scheme

Abstract

A multivariate optimization scheme (MOS) was used to investigate the effects of environmental variables and supercritical fluid extraction (SFE) parameters on the extractability of pesticide residues from soil samples. MOS is a highly efficient technique for studying a large number of variables and identifying optimal extraction conditions. MOS offered the opportunity to systematically and simultaneously examine the interaction and effect profiles among important soil variables and extraction parameters. Pesticide residence time in soil had a major influence on binding extent for all tested pesticides. Extractability as a function of soil composition was greatly dependent on the particular pesticide examined. Bensulfuron-methyl was the most difficult to extract from soils containing high levels of both organic matter and clay. Atrazine was extracted more easily than diuron. High organic matter and high clay content led to strong binding for diuron and atrazine, respectively. Effects of SFE parameters on extractability appeared to depend on the nature of residues (e.g., freshly fortified versus aged residues). For freshly fortified samples, analyte solubility in supercritical fluid and/or modified supercritical fluid was the critical factor as indicated by the strong influence of pressure on extraction efficiency. For aged samples, temperature was an important determinant of extraction efficiency, indicating that mass transfer or diffusion processes were rate-limiting. The presence of modifier and extraction duration also significantly impacted extractability of aged pesticides.

Decontamination of hazardous substances from solid matrices and liquids using supercritical fluids extraction: A review

“…It is confirmed that the extractability of pesticide residues from soil samples is strongly affected by environmental variables and SFE parameters. To further verify the most significant variables, a multivariate optimization scheme (MOS) was employed by Zhou et al [120] to investigate the effects of those parameters on the extractability of several pesticides from soil. Later, they concluded that the extractability of pesticides residues from soil was also dependent on the particular pesticide examined and on the nature of residues.…”

Chemical and physical factors affecting the extractability of methidathion from soil samples.

“…Experimental designs are well suited to optimisation of experimental conditions which are known to influence the final results [21,23,31,32]. Accordingly, a full factorial was designed for the determination of the significant factors (humidity, solvent type, and sterilisation method) affecting the analytical system under study.…”

“…Many procedures have been proposed for the extraction of organic contaminants from soil, including accelerated solvent extraction [19,20,21,22], supercritical-fluid extraction [21,22,23], and microwave-assisted extraction [24] which, in addition to increased analytical speed, lessen the cost per sample by reducing solvent consumption. However, they usually require sophisticated equipment not always available in modest laboratories.…”

Supercritical fluid extraction as a useful method for pesticides determination

“…R e c e n t ly, a mu l t iva ri ate optimization scheme has been applied to the SFE of pesticide residues (atrazine, diuron and bensulfuron-methyl) from soils, using a quadratic model and a central composite design, and considering two groups of independent variables (soil environmental variables and SFE parameters) [55]. The analyte residence time in the soil was the most significant env i ronmental fa c t o r. Th e n , for age d samples (12 months), the soil organic matter and clay minerals content had a negative effect on the recoveries due to stronger analyte-matrix interactions (especially for bensulfuron-methyl).…”