测定电解锰中微量铁的 FAAS法——采用 EDTA作释放剂

用盐酸溶解试样,加入EDTA等螯合剂作释放剂,通过改变燃烧器高度调整原子蒸气的温度以消除99．8％以上基体锰的干扰,然后用原子吸收光谱法直接测定电解锰中微量的铁,获得了满意的结果。其标准曲线法、标准加入法的结果相吻合,样品加标回收率99．8％,相对标准偏差为3．1％。方法简便快速,适于工厂的快速分析。     

纳米SnO2的非水溶剂溶胶-凝胶法制备与表征

Nanometer SnO₂ powders were successfully prepared by non-hydrolytic sol-gel approach combined with heat treatments using tin tetrachloride as starting material and ethylene glycol as solvent. The reaction mechanism of the sol-gel process is proposed. Results indicate that the -OHCH₂CH₂OH- prevent Cl^- ion from accessing to tin Sn⁴⁺ due to steric effect, and hence increaseing the stability of the sol solution. Ethylene glycol functions not only as a complextion agent to form a polymer network but also as a “spacer” to modulate the distance between metal ions, preventing metal oxide particles from aggregation during desiccation of the sol. The effects of heat treatments on the evolution of structure and morphology of nanosized SnO₂ powders were studied. The powders with narrow size distribution around 15～20 nm could be obtained at 500 ℃ for 4 h.