Residue Analysis And Digestion Dynamics Of 25% Strypoxol Suspension In Tobacco And Soil

Flutriafol is a triazole fungicide and widely used to prevent and cure the straw, panicle disease and soil-spread diseases of cereal crops, such as powdery mildew, rust, sheath blight, leaf spot, web blotch, smut, etc. Flutriafol had special control effect on grain powdery mildew, and it was used to prevent powdery mildew of tobacco in China. The action mechanism is to inhibit the growth of hypha on account of disruption of fungal cell wall which was inhibited by the biosynthesis of ergosterol.Flutriafol was extracted with dichloromethane, and cleaned-up by C18 and N-propyl-ethylenediamine(PSA) in soil and tobacco. The limit of detection(LOD) and limit of quantification(LOQ) were established at signal-to-noise ratio(S/N) of 3:1 and 10:1, and were determined to be 0.006 and 0.02 mg kg-1 in soil, 0.033 and 0.1 mg kg-1 in tobacco, respectively. Recovery experiments were carried out to value the stability and precision of the established method, the results indicated that the average recovery values of soil, green tobacco leave and cured tobacco leave samples were ranged from 77.63 to 101.7%, 81.03 to 92.82%, 72.85 to 97.76%, respectively. Thus, the newly established method was rapid, sensitive and accurate in flutriafol determination in soil, green and cured tobacco leaves. In the year of 2013, dissipation of flutriafol could be described by the first order kinetics equations Ct = 0.4074e-0.0312t(Huishui) and Ct = 0.8184e-0.0510t(Changsha), and the initial concentrations were 0.58 and 0.98 mg kg-1 in Huishui and Changsha, respectively. On the condition of low dose of 120 g a.i. ha-1, the terminal residual levels in cured tobacco leaves and soil were ranged from 0.92 to 6.84 mg kg-1 and 0.02 to 0.12 mg kg-1; on the condition of high dose of 180 g a.i. ha-1, the terminal residual levels in cured tobacco leaves and soil were ranged from 0.89 to 14.67 mg kg-1 and 0.04 to 0.29 mg kg-1In conclusion, in current study, an analytical method for detection of flutriafol was established, and the terminal maximum residue limit(MRL) of flutriafol in cured tobacco leave is 14.67 mg/kg. This study first reported the MRL of flutriafol in tobacco plant, and set the reference data for the safe usage of tobacco in China...