Determination of residues of furalaxyl and metalaxyl in nutrient solution, peat compost and soil samples by gas chromatography
Rapid and sensitive techniques for the determination of residues of the fungicides furalaxyl and metalaxyl in agricultural samples are described. Air-dried soils and peat composts are extracted with acetone in a Soxhlet apparatus; the extract is applied directly to the gas chromatograph and detected using a nitrogen-selective detector. Plants are macerated with acetone and, after filtration and dilution with water, partitioned with chloroform; nutrient solutions are similarly extracted with chloroform. The extracts are subjected to gas chromatography after removal of chloroform and dissolution in acetone. Recoveries are generally better than 80% with detection limits of 0.5 mg kg–1 for peat, 0.1 mg kg–1 for soils and plants and 0.02 mg kg–1 for nutrient solutions.