A Study On Residue Analysis And The Residual Dynamic Of Rimsulfuron In Potato

Rimsulfuron is a kind of sulfonylurea inhale-herbicide preventing annual and perennial germanous or broad-leaved weed in potato field. which is exploited by the DuPont corporation. The sulfonylurea herbicide is applied at large because of its some characters, such as low-dosage, high-efficiency, low-toxin and its particular function. Due to the fact sulfonylurea herbicide is used in very low doses analysis of such residues is a challenging job.A HPLC method was effective for detecting Rimsulfuron residuum in potato soil, plant and potato tuber. Before purifying by C18. the samples should be extracted by acetonitrile, followed by a second extraction in chloroform, and then would be determined by HPLC with UV detection at220nm, acetonitrile and0.1%Ethanoic Acid aqueous solution (60:40, by vol) as a mobile phase. The different addition level of potato soil and potato plant were0.2mg/kg、1.0mg/kg and2.0mg/kg.The results showed that the average recoveries were91.0%～92.6%for plants,96.7%～99.4%for soils. The relative standard deviation was1.0%～4.5%and5.1%～8.5%. the limits of detection was2.6×10-10g, the limits of quantification was2.0×10-3mg/kg. Residual trial of Rimsulfuron was conducted in Jilin and Shandong during2010～2011. A two year field trial showed that the results indicated that degradation of Rimsulfuron in plant and soil samples was accordance with the kinetic equation C=C0e-kt.The half-lives of Rimsulfuron in soil and in plant were0.02～3.1and0.93～2.9days.The degradation ratio was almost more than80%in soil7days later and the degradation ratio was more than80%in plant7days later. And the results showed that Rimsulfuron was apt to degrade in soil and plant(T1/2<30d). The potato was sprayed one time with25%Rimsulfuron WP according to the recommended dosage90g/hm2and high dosage135g/hm2. A two year field trial showed the final residues of Rimsulfuron were not detected in potato plant and potato tuber.。This analysis method for the first time used the HPLC method for the determination of Rimsulfuron residue in soil and potato plant. The method is both convenient and satisfies the requirement of residue analysis. The FAO and the WHO does not make Rimsulfuron in potato residue limits standard, the European Union rules Rimsulfuron in potato of MRL is1mg/kg。As the test results a suggested dosage90g/hm2of25%Rimsulfuron WP was recommended to use in the potato field. The MRL of Rimsulfuron in potato may be advised to be1mg/kg.