Photodegradation of fenitrothion and parathion in tomato epicuticular waxes.
Photodegradation of (14)C-labeled fenitrothion ([O,O-dimethyl O-(3-methyl-4-nitrophenyl) phosphorothioate]) and parathion ([O,O-diethyl O-(4-nitrophenyl) phosphorothioate]) was conducted on a series of solid surfaces including isolated tomato fruit and leaf cuticle waxes. The wax-coated glass plate gave the comparative degradation of fenitrothion observed for the intact plant but both surfaces of octadecyl-capped silica gel and poly(tetrafluoroethylene) enhanced its volatilization. Photoinduced desulfuration and ester cleavage were common to both pesticides in waxes, but formation of the azo derivative was found to be a major degradation pathway characteristic of parathion. The modified electronic states of the nitro group by introduction of m-methyl group accounted for this different photoreactivity based on molecular orbital calculations.
Fukushima
Masao
M
Environmental Health Science Laboratory, Sumitomo Chemical Co., Ltd., 2-1, Takatsukasa 4-chome, Takarazuka, Hyogo 665-8555, Japan.
Katagi
Toshiyuki
T
D005278:Fenitrothion / Q000737:chemistry*; D007306:Insecticides / Q000737:chemistry*; D007700:Kinetics; D008027:Light; D018551:Solanum lycopersicum / Q000737:chemistry*; D010278:Parathion / Q000737:chemistry*; D010782:Photolysis; D013056:Spectrophotometry, Ultraviolet; D017550:Spectroscopy, Fourier Transform Infrared; D014885:Waxes / Q000737:chemistry*
D007306:Insecticides; D014885:Waxes; D010278:Parathion; D005278:Fenitrothion