GAS-CHROMATOGRAPHIC METHOD FOR DETERMINATION OF URACIL HERBICIDES IN ROOTS OF ECHINACEA-ANGUSTIFOLIA MOENCH (ASTERACEAE)

A GC/NPD method and a rapid screening TLC method were developed for th e simultaneous determination of uracil herbicide residues (bromacil, l enacil, terbacil) in the roots of Echinacea angustifolia Moench (Aster aceae). The uracil herbicide residues were extracted into acetone. Aft er evaporation of acetone from the acetone-water extract the residue w as dissolved in water-methanol (5:1 v/v). Cyclohexane was used for rem oval of the non-polar co-extractives in the sample matrix. After separ ation of the cyclohexane phase the uracil herbicide residues were extr acted into chloroform. This extract was purified on a Florisil(R) colu mn, and residues were eluted with dichloromethane-acetone (9:1, v/v). The cleaned up extract was analysed by the GC/NPD method on a capillar y column DB-1 using atrazine as internal standard. A minimum recovery of 70% was attained for contamination levels of 0.02-0.40 mg kg(-1). ( C) 1998 Elsevier Science B.V.