重铬酸钾容量法测定溶液中全铁含量的研究

The research of potassium bichromate capacity method about determining total iron content

采用标准物质纯铁粉配制成标准浓度的铁离子标准溶液作为理论值,用基准物质重铬酸钾配制成标准滴定溶液测定溶液中的全铁含量,通过将测定结果与理论值比对,研究了影响测定结果准确度的因素。主要研究了试剂空白试验消耗体积的计算公式对测定结果准确度的影响,推导出了更加准确的空白值计算公式。结果表明,按推导的空白值计算公式计算全铁含量的结果与真实值之间相对误差的绝对值降低,由原来的0.94%降低到了0.15%。对影响测定结果的其它因素如:铁离子标准溶液的配制方法、酸度调节、还原剂的加入量、加热温度调节等进行了研究,提出了避免误差产生的技术要点。

Adopting the iron ion standard solution with standard concentration prepared from pure iron powder reference material as theoretical value,the total iron content in solution was determined with standard titrimetric solution prepared with primary standard substance—potassium bichromate.According to the contrastion of analysis result and theoretical value,the influential factors on degree of accurancy were discussed.The major research is the influence of the calculate formula of reagent blank consume volume on degree of accurancy,eliciting the more accuracy calculate formula of using reagent blank to do.The result shows that,the absolute relative error between calculate result and true value for using new elicited calculate formula is cut down,decreasing from 0.94percent to 0.15percent.There are other factors that affect its result,for example,the iron ion standard solution preparation,acidity adjustment,the addition of reductive agent,adjustment of heating temperature,and so on,all be discussed,and the technical essentials for avoiding error production were introduced.