Photodegradation of Emamectin Benzoate in Aqueous Solutions

Abstract

The half-life of [14C]4‘‘-deoxy-4‘‘-(epi-methylamino)avermectin B1a (MAB1a) benzoate (1 ppm) photodegradation in buffer (pH 7), natural pond water, and sensitized buffer (1% acetone in pH 7 buffer) determined at Three Bridges, NJ (latitude ∼40° N) during the fall season under natural sunlight was 22, 7, and 1 days, respectively. The half-life of [14C]MAB1a benzoate (10−12 ppm) photodegradation in buffer (pH 7) containing 1% (v/v) acetonitrile, ethanol, or acetone as cosolvent under continuous exposure with a xenon lamp was 64.5, 8.5, or 0.5 days, respectively. The photoisomer 8,9-Z-MAB1a, 8a-hydroxy-MAB1a, and unknown polar residues were found in light-exposed samples of MAB1a in buffer and natural pond water. In light-exposed sensitized buffer samples, 8a-oxo-MAB1a and MAB1a-10,11-14,15-diepoxide were additional products. Very polar residues found in the organic and aqueous phases after extraction increased with time, and their formation followed the order sensitized buffer ≫ natural pond water > buffer. Keywords: MK-0244; emamectin benzoate; photodegradation; residues

Influence of different materials on the concentration of delousing agents in sea water during bioassays

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“…The involvement of pressing wavelengths below 290 nm with transmission hydroxyl radicals was discarded on the basis of the lack of filters. The observed half-life times varied from 10 to 40 influence of isopropanol. The authors suggest the phenol min in the presence of TiO , one or two orders of may react with positive holes in goethite, the electron 2 magnitude lower than in its absence.…”

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