Näykki T, Raimo A, Paavo P, Antero K, Päivi N
Department of Chemistry, University of Oulu, PO Box 3000, 90401 Oulu, Finland.
Talanta. 2000 Jul 31;52(4):755-60.
The aim of the work was to find a suitable method and conditions for determining Na(2)O wt.% from NaAlO(2). Problems were encountered while titrating NaAlO(2) with hydrochloric acid. The problematic area was the pH range 4-10 where aluminum precipitates as hydroxides. The different species of the aluminate solution were determined using potentiometric and complexometric titrations. The equivalent point of the potentiometric titration was detected using Gran's plotting method. Precipitation of aluminum hydroxides did not interfere with titrations, because in potentiometric titrations the pH value was over 10 and in complexometric titrations the pH was 4. The results were accurate and determinations were easy to carry out. Sodium was also determined by DCP-AES.
这项工作的目的是找到一种合适的方法和条件来测定偏铝酸钠中氧化钠的质量分数。在用盐酸滴定偏铝酸钠时遇到了问题。有问题的区域是pH值为4至10的范围，在此范围内铝会以氢氧化物形式沉淀。使用电位滴定法和络合滴定法测定铝酸盐溶液的不同物种。使用格兰作图法检测电位滴定的等当点。氢氧化铝的沉淀不干扰滴定，因为在电位滴定中pH值超过10，而在络合滴定中pH值为4。结果准确，测定易于进行。钠也通过直流等离子体发射光谱法进行测定。
