Supercritical fluid extraction of 2,4-D from soils using derivatization and ionic modifiers

Supercritical fluid extraction (SFE) with CO 2, a clean and rapid alternative to conventional organic solvent extraction techniques, was investigated for the extraction of 2,4-D from soils using a variety of pre-extraction soil treatments to enhance extraction recoveries. Initial experiments with silylation, ion-pairing, methyl esterification, and ionic displacement are reported. Methyl esterification and ionic displacement during SFE proved to be the most promising approaches for quantitative extraction. Although the SFE procedures were not fully optimized, comparison between SFE and a standard Soxhlet extraction method demonstrated the potential for improving analytical measurement for highly polar pesticides in soil by modifying SFE—CO 2 extraction with derivatizing reagents and ionic solutions.