春雷霉素在水稻田水和土壤中的残留及消解动态

采用固相萃取(SPE)和高效液相色谱(HPLC)建立了一种检测水稻田水和土壤中春雷霉 素残留的方法。田水样品直接过滤后经阳离子固相萃取(SCX-SPE)柱净化;土壤样品用V(丙酮)∶V(水)=3∶7的混合溶液超声提取后经相同方法净化。以庚烷磺酸钠为离子对试剂,采用离子对反相高效液相色谱法(IP-HPLC)进行检测。方法的线性范围在0.05~5.0 mg/L之间,相关系数(r)为0.999 9。当春雷霉素在田水和土壤中的添加水平分别为0.01~0.5 mg/L和0.01~0.5 mg/kg时,其在田水中的平均回收率在83.8%~92.4%之间,相对标准偏差(RSD)为3.67%~5.21%;土壤中的平均回收率在79.7%~84.5%之间,RSD为4.39%~5.62%。方法的检出限(LOD)在田水和土壤中分别为0.001 mg/L和0.001 mg/kg,定量限(LOQ)分别为0.01 mg/L 和0.01 mg/kg。采用所建方法对广东、广西和湖北3地2011年春雷霉素在田水及土壤中的消解动态进行了检测。结果表明:其在水稻田水及土壤中的消解动态曲线均符合一级动力学方程;在田水中消解迅速,半衰期分别为2.88 d(广东)、2.52 d(广西)和2.68 d(湖北);在土壤中的消解速率比水中的慢,半衰期分别为4.12 d(广东)、5.41 d(广西)和4.89 d(湖北),属于易降解农药(t1/2 < 30 d)。

Residue and decline study of kasugamycin in paddy water and paddy soil

A method for the determination of kasugamycin residue in paddy water and soil was established by means of SCX-solid phase extraction(SPE)and high performance liquid chromatography(HPLC).The paddy water sample was filtrated directly and then cleaned up by SCX-SPE column,while the samples in soil were extracted with V(acetone)∶V(water)=3∶7 by ultrasonic wave and cleaned up by SCX-SPE column.The kasugamycin was determinated by ion-pair reversed-phase high performance liquid chromatography(IP-HPLC)with heptane sulfonicacid sodium.The linear ranges were 0.05-5.0 mg/L and 0.01-0.5 mg/kg with the linear correlation coefficient of 0.999 9.The average fortification recovery of paddy water was 83.8%-92.4% with relative standard deviation(RSD)of 3.67%-5.21% and that of paddy soil was 79.7%-84.5% with relative standard deviation(RSD)of 4.39%-5.62% when kasugamycin was spiked at 0.01-0.5 mg/L level.The limits of detection(LOD)for kasugamycin was 0.001 mg/L in paddy water,and 0.001 mg/kg in paddy soil.The limits of quantification(LOQ)for kasugamycin in paddy water and paddy soil were 0.01 mg/L and 0.01 mg/kg.The method was used to detect the degradation of kasugamycin in the paddy water and soil in Guangdong,Guangxi and Hubei in 2011.The degradation research of kasugamycin in paddy water and soil suggested that the decline curves accorded with the first-order kinetics equation.Kasugamycin declined fast in paddy water,the half-life of kasugamycin in paddy water was 2.88 d(Guangdong),2.52 d(Guangxi) and 2.68 d(Hubei),respectively.Kasugamycin declined slower in the paddy soil than in the paddy water.The half-life of kasugamycin in paddy soil was 4.12 d(Guangdong),5.41 d(Guangxi)and 4.89 d(Hubei),respectively,indicated that the Kasugamycin was digested easy in the paddy soil and paddy water.