EVALUATION OF AN EXTRACTION METHOD FOR TRIAZINE HERBICIDES FROM SOILSFOR SCREENING PURPOSES

With spiked standard soils and natural field samples the extractabilit y of the corn herbicides atrazine and terbuthylazine has been studied. As pre-treatment drying at room temperature and a short storage perio d proved to the best. With an ultrasonic extraction especially methano l or a methanol/water-mixture showed satisfactory extraction efficienc ies, yet deionized water showed with many soils equally high recoverie s nor did any of the extractants ensure exhaustive extraction of spike d residues. Even methanolic soxhlet extraction and supercritical fluid extraction (methanol as the modifier) gave no significant rise in yie ld. Because concentrations in aqueous extracts may be determined witho ut further clean-up nor dilution in immunoassays, aqueous ultrasonic e xtraction shows most advantages for a screening procedure with - on an average - satisfactory extraction efficiency.