No abstract

Homogeneous sample pulp, prepared from fruits and vegetables of different water content with or without additional water, Is adsorbed on the surface of activated Florisll to obtain a free-flowing powder, which is extracted In a glass column with ethyl acetate or methylene chloride-acetone (9 + 1, v/v). In most cases, no further cleanup Is necessary for subsequent gas chromatographic measurement. The recovery of pesticide residues, Including carbamate, organochlorlne, organophosphate, synthetic pyrethrold, triazlne, urea, and miscellaneous pesticides, Is generally ≥80%, and Is Independent of the sample material. The column extraction Is faster, less laborious, and less expensive than extractions based on traditional techniques, liquid partition, or other conventional chromatographic procedures.

The P-o-glucoside conjugate of [14C]'hydroxymonolinuron', [phenyl-14C]-3-(4chlorophenyl)-l-(hydroxymethyl)-l-methoxyurea-~-~-glucos~de (HM-8-GI and its soil-bound residues, prepared as described, were used to estimate its bioavailability to earthworms and ryegrass plants. The results demonstrate that these bound residues were available to both earthworms and ryegrass. The concentration in the earthworms, expressed on a dry weight basis after 42 days of exposure, was equal to the surrounding soil. The earth worms were found to be more efficient in remobilising and absorbing soil-bound residues than ryegrass plants after 59 days of cultivation. Fractionation of the soil-bound residues showed that 29% of the radiocarbon was associated with fulvic acid, 20% with humic acid and 9 % with the humin fraction. 4-Chlorophenylurea, a metabolite of HM-B-G proved to be a key compound in the formation of soil-bound residues. The amount of radioactivity (bound residues), recovered from soil through solubilisation by means of O.s~-acid and alkali, seems to be a criterion for predicting the bioavailability of bound phenylurea residues. The half-life of soil-bound residues was estimated to be about 4.6 years.

No abstract

No abstract