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RESEARCH PRODUCT

Solid-phase extraction disks for determining pesticides from soil leachates

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Abstract Analytical techniques are essential for identifying and quantifying the chemicals present in environmental samples. A method for extracting pesticides from soil leachates was developed. The proposed method is based on solid-phase extraction and uses 47-mm disks of octyl-bonded silica. Analysis was carried out by gas chromatography with nitrogen–phosphorus and electron-capture detectors. Several factors that can provide better pesticide recoveries with this extraction method are discussed. These factors are: the kind and percentage of organic solvent used in the extraction procedure, the volume and the ionic strength (adding 15% of NaCl) of the aqueous phase which passes through the octyl-bonded silica sorbent. Finally, the proposed method was used to determine the pesticide concentration of leachates from soil samples taken from different plots of an important intensive agricultural area.