室内条件下土壤含水量对烟嘧磺隆消解的影响

采用高效液相色谱-紫外光谱(HPLC-UV)法,研究了烟嘧磺隆在不同含水量土壤中的消解动态,分析了土壤含水量对其消解的影响。土壤样品经V(乙腈)∶V(磷酸盐缓冲溶液)=1∶4提取,采用HPLC-UV法检测不同含水量的土壤中烟嘧磺隆的残留量。结果表明:在0.25~4 mg/L范围内,烟嘧磺隆峰面积与其质量浓度呈良好线性关系,相关系数为0.999 9。在0.05、0.25和1.25 mg/kg 3个添加水平下,烟嘧磺隆的回收率为91%~106%,相对标准偏差(RSD)为5.4%~9.5%。检出限(LOD)为0.012 mg/kg,定量限(LOQ)为0.04 mg/kg。当土壤含水量小于50%时,土壤水分含量变化对烟嘧磺隆消解的影响较小;当含水量大于50%时,烟嘧磺隆消解半衰期呈先增大后减小趋势,其中在含水量为60%和90%的土壤中消解最快,半衰期分别为19.7和18.6 d。

Effect of water content in soil on the dissipation of nicosulfuron in the indoor condition

The dynamics of dissipation and half-life of nicosulfuron with different water content in soil, and the effect of water content in soil on the dissipation of nicosulfuron was studied. Soil samples were extracted with V (acetonitrile):V(phosphate buffer solution)=1:4, and the residue of nicosulfuron was determined by high performance liquid chromatography with UV detector (HPLC-UV). Linear correlation of nicosulfuron was 0.999 9 with concentration between 0.25-4 mg/L. The results of fortified experiment showed that the recovery was 91%-106%, with relative standard deviation (RSD) between 5.4%-9.5% on the fortified level of 0.05, 0.25 and 1.25 mg/kg. The limit of detection (LOD) for nicosulfuron was 0.012 mg/kg, and the limit of quantification (LOQ) of the method was 0.04 mg/kg. Water content in soil has only a little effect on the half-life of nicosulfuron when water content was below 50%. The half-life increased first and decreased later when water content was over 50%. The dissipation rate of nicosulfuron was the highest with 60% and 90% water content in soil, the half-life was 19.7 and 18.6 d, respectively.