| Abstract: | Investigations have been carried out on residues of linuron and its breakdown products in carrots sprayed with Jinuron at 1, 2, or 4 kg a.i./ha, 0, 19, 28, 36 or 60 days after sowing (up to 57 days before harvesting). The extracted residues were separated into three fractions by liquid-liquid partitioning: (a) linuron, (b) 3-(3,4-dichlorophenyi)-l-methoxyurea, 3-(3,4-dichlorophenyl)-l-methylurea, 3,4-di-chlorophenylurea and (c) 3,4-dichloroaniline. The compounds in each fraction were hydrolysed and the iodine derivative 1,2-dichloro-4-iodobenzene was formed by a Sandmeyer reaction between 3,4-dichloroaniline and iodide ion, followed by gas chromatography with electron capture detector. Only 5-13% of the extract-able residues were breakdown products. Most of the detectable residue (87-95%) was identified as linuron. The relative proportions of linuron and breakdown products in carrots at the time of harvest were not affected by the time of spraying or the interval between treatment and harvest. |
