[Objective] This study aimed to establish a determination method for iprobenfos residue in rice straw and husked rice. [Method] The rice straw and husked rice samples were extracted by acetone-ethyl acetate mixed solv...[Objective] This study aimed to establish a determination method for iprobenfos residue in rice straw and husked rice. [Method] The rice straw and husked rice samples were extracted by acetone-ethyl acetate mixed solvent. The extracts were purified using SPE C18 column and SPE NH2 column, and the iprobenfos residues were determined by GC-FTD. [Result] In the concentration range of 0.005-5.0 mg/kg, iprobenfos concentration showed a good linear relationship with peak area （r=0.999 8）. When the iprobenfos concentrations were 0.01, 0.1 and 1.0 mg/kg respectively, the recoveries of added iprobenfos from rice straw ranged from 72.6% to 99.7% with relative standard deviation ranging from 5.65% to 8.48%; the recoveries of added iprobenfos from husked rice ranged from 81.6% to 97.6% with relative standard deviation ranging from 3.74% to 7.63%. The minimum detectable quantity of iprobenfos was 5×10^-12 g, and the minimum detectable concentrations of iprobenfos in rice straw and husked rice samples were 2.0 and 0.5 μg/kg, respec- tively. [Conclusion] The established determination method is characterized by low de- termination limit, high sensitivity, good reproducibility and high operability, which all meet the requirements by Guideline on Pesticide Residue Trials of the Ministry of Agriculture.展开更多
The rice husk ash （ RHA） and silica （ Si02） nanoparticles are prepared from rice husk charcoal （RHC） by the methods of ventilated calcining and chemical precipitation, respectively, to remove the residual carbon...The rice husk ash （ RHA） and silica （ Si02） nanoparticles are prepared from rice husk charcoal （RHC） by the methods of ventilated calcining and chemical precipitation, respectively, to remove the residual carbon which is harmful to cement composites. The structures and morphologies of these products are investigated by the Fourier transform infrared spectroscopy, X-ray diffraction, scanning/ transmission electron microscopy and N2 adsorption- desorption analyzer. The results show that the as-produced RHA and Si02 nanoparticles exist in amorphous phase without residual carbon, and exhibit porous structures with specific surface areas of 170.19 and 248. 67 m2 /g , respectively. The micro particles of RHA are aggregated by numerous loosely packed Si02 gel particles with the diameter of 50 to 100 nm. The Si02 nanoparticles are well dispersed with the average size of about 30 nm. Both the RHA and Si02 nanoparticles can significantly reduce the conductivity of saturated Ca（OH）2 solution and increase the early strength of the cement composites. They also exhibit high pozzolanic activity, indicating that they can be used as ecological nano mineral admixtures.展开更多
基金Supported by Pesticide Registration Residual Test of Institute for the Control of Agrochemicals,Ministry of Agriculture(2013F216)~~
文摘[Objective] This study aimed to establish a determination method for iprobenfos residue in rice straw and husked rice. [Method] The rice straw and husked rice samples were extracted by acetone-ethyl acetate mixed solvent. The extracts were purified using SPE C18 column and SPE NH2 column, and the iprobenfos residues were determined by GC-FTD. [Result] In the concentration range of 0.005-5.0 mg/kg, iprobenfos concentration showed a good linear relationship with peak area （r=0.999 8）. When the iprobenfos concentrations were 0.01, 0.1 and 1.0 mg/kg respectively, the recoveries of added iprobenfos from rice straw ranged from 72.6% to 99.7% with relative standard deviation ranging from 5.65% to 8.48%; the recoveries of added iprobenfos from husked rice ranged from 81.6% to 97.6% with relative standard deviation ranging from 3.74% to 7.63%. The minimum detectable quantity of iprobenfos was 5×10^-12 g, and the minimum detectable concentrations of iprobenfos in rice straw and husked rice samples were 2.0 and 0.5 μg/kg, respec- tively. [Conclusion] The established determination method is characterized by low de- termination limit, high sensitivity, good reproducibility and high operability, which all meet the requirements by Guideline on Pesticide Residue Trials of the Ministry of Agriculture.
基金The Key Program of the National Natural Science Foundation of China(No.51438003)the National Basic Research Program of China(973 Program)(No.2015CB655105)
文摘The rice husk ash （ RHA） and silica （ Si02） nanoparticles are prepared from rice husk charcoal （RHC） by the methods of ventilated calcining and chemical precipitation, respectively, to remove the residual carbon which is harmful to cement composites. The structures and morphologies of these products are investigated by the Fourier transform infrared spectroscopy, X-ray diffraction, scanning/ transmission electron microscopy and N2 adsorption- desorption analyzer. The results show that the as-produced RHA and Si02 nanoparticles exist in amorphous phase without residual carbon, and exhibit porous structures with specific surface areas of 170.19 and 248. 67 m2 /g , respectively. The micro particles of RHA are aggregated by numerous loosely packed Si02 gel particles with the diameter of 50 to 100 nm. The Si02 nanoparticles are well dispersed with the average size of about 30 nm. Both the RHA and Si02 nanoparticles can significantly reduce the conductivity of saturated Ca（OH）2 solution and increase the early strength of the cement composites. They also exhibit high pozzolanic activity, indicating that they can be used as ecological nano mineral admixtures.
