Famoxadone residue and dissipation in watermelon and soil

The residue levels and dissipation rate of famoxadone in watermelon and soil were determined by HPLC-UVD. The LODs for famoxadone in watermelon, peel, flesh and soil were 0.002mg/kg (0.004mg/kg in leaf). The fortified recoveries ranged from 84.91% to 99.41% with relative standard deviations (RSDs) of 0.06-4.50%. The dissipation of famoxadone residue over the time in watermelon leaf and soil fitted to the equation C(T)=19.695e(-0.078T) and C(T)=1.369e(-0.129T). The half-lives (T(1/2)) of famoxadone in watermelon leaf and soil were 9.7 and 5.5 days, respectively. The final residue in watermelon was lower than 0.1mg/kg at harvest, which suggested the use of this fungicide to be safe to both human and environment. This work would be helpful in establishing the maximum residue limit (MRL) for famoxadone in watermelon in China, and provide guidance to the proper and safe use of this pesticide in agriculture.