Ethoysulfuron Residue Dynamics In Rice And Adsorption Study Of Ethoysulfuron

The residue dynamics of ethoxysulfuron was studied in paddy,water and soil.samples were extracted with methanol and acetonitrile,dichloromethane by liquid-liquid partition,cleaned up by C18 and alumininia chromatographic column,and determinated by HPLC-VWD.The residue dynamics accumulation and ultimately residue of ethoxysulfuron were detected by HPLC.The limit of detection of HPLC was 5.6×10-10 g,The limit of quantification of ethoxysulfuron by HPLC were 0.0045 mg·kg-1,0.022mg·kg-1,0.0028 mg·kg-1 and 0.011 mg·kg-1.The average recoveries of the method was 94.8-96.7% for soil samples,90.6-95.5% for plant samples,95.8-98.8% for water samples,93.9-98.8% for rice samples,86.0-93.8% for paddy samples,respectively.The accuracy and precision of the method accorded with the demands of pesticide residues analysis.When high dosage 20.25a.i.g/hm2 15%ethoxysulfuron WG was applied in plant,soil and water,Two years' field test showed that residue of ethoxysulfuron in plant were 0.25-1.23 mg·kg-1 original respectively,the half-life of ethoxysulfuron was 1.9-12.7 d.The residue of ethoxysulfuron in soil were 0.06-0.86 mg·kg-1 original respec-tively, the half-life of ethoxysulfuron was 0.1-7.8 d.The residue of ethoxysulfuron in water were 0.11-1.79 mg·kg-1,the half-life of ethoxysulfuron was 0.7-3.4 d in water.The degradation procedure of ethoxysulfuron scribed by first-order kinetics equation C=C0e-kt,In plant,the dynamic equation in 2009 and 2010 were C=0.8617e-0.0556t(2009 Jilin);C=0.251e-0.2656t(20 09 Heilongjiang);C=0.2754e-0.4021t(2010 Hunan).C=0.8514e-0.0893t(2010 Jilin); C=0.3594e-0.209 1t(2010 Heilongjiang); C=0.262e-0.0759t(2010 Hunan).In soil,the dynamic equation in 2009 and 2010 were C=0.0613e-0.0512t(2009 Jilin);C=0.0502e-0.1254t(2009 Heilongjiang);C=0.3214e-0.0522t(2009 Hunan).C=0.0582e-0.0406t(2010 Jilin); C=0.0894e-0.0733t(2010 Heilongjiang); C=0. 0502e-0.0749t(2010 Hunan). In water,the dynamic equation in 2009 and 2010 were C=0.21 79e-0.5326t(2009 Jilin);C=0.2208e-1.0187t(2009 Heilongjiang);C=0.2373e-0.2802t(2009 Hunan).C=0. 168e-0.4546t(2010 Jilin);C=0.105e-0.1901t(2010Heilongjiang);C=1.6285e-0.8517t(2010 Hunan).The degradation rate was more than 90% in plants soil and water after 30 days,the results showed that etho-xysulfuron is easy to degrade in plant soil.and water.The final residual concentration of ethoxysulfuron in plant of paddy,soil,rice and paddy was determined.Two years' field test showed that,when 15% 20.25 a.i.g/hm2,13.5 a.i.g/hm2 ethoxysulfuron WG was applied in paddy;the final residue of ethoxysulfuron in plant of paddy,soil,rice and paddy fell below detectable limit.The adsorption of ethoxysulfuron by soil was studied by equilibrium method.Five different soil types were used in the study.ethoxysulfuron solutions(20mL) of different density were added to soil (1g) and were shaken at 25℃,A HPLC method was carried out to detect the ethoxysulfuron amount in water after 24 hours.The result showed that the adsorption of ethoxysulfuron was mainly influenced by organic carbon content.The results indicated that the adsorption were fitted to the Freundlich eauation.