Extraction of procymidone from alkaline soils

Analysis of pesticide residues in soil samples frequently requires multi-stage processes and incurs substantial variability. There is interest, therefore, in developing a method of extraction that are both simple (requiring few steps), efficient (giving high recovery) and robust (with similar efficiency for a wide range of samples). Methods that use small amounts of organic solvents have the advantage of small amounts of waste and low laboratory hazard. Three extracting methods, solvent shaking, Supercritical Fluid Extraction (SFE) and Accelerated Solvent Extraction (ASE) were assessed for the extraction efficiency of procymidone residues in a variety of Mediterranean alkaline soils. Overall average procymidone recoveries were 70% shaking with methanol, 84% with supercritical CO2 modified with methanol, and 94.6% with acetone using accelerated solvent extraction. ASE demonstrated better recovery, faster extraction, and less risk of procymidone breakdown than SFE or shaking. SFE performed equally well as ASE, but moisture and organic content affected the recovery of some soil samples. Solvent shaking was not as efficient as SFE and ASE; the recovery could have been affected by the low spiking rare used.