基于电位滴定法测定氧化铁粉中氯离子

Study on the Determination of Chloride Ions in Iron Oxide Based on Potentiometric Titration

采用自动电位滴定法,以0.01 mol/L硝酸银标准溶液作为滴定剂,通过对试样称样量、试样中加入酸的种类及滴定前搅拌时间等参数进行优化,确定检测氧化铁粉中氯离子含量的最优方法,并通过加标回收实验验证了分析结果的准确度。实验结果表明:当称样量为0.5 g,加入10 mL 10%磷酸,搅拌时间为120 s时,分析结果的精密度和回收率均满足生产需求。

The automatic potentiometric titration method is adopted,and 0.01 mol/L silver nitrate standard solution is used as the titrant.The optimal method for detecting the chloride ion content in iron oxide powder is determined by optimizing the parameters such as the sample weight,the type of acid added to the sample,and the stirring time before titration.The accuracy of the analysis results was verified through spiked recovery experiments.The experiment results show that when the sample size is 0.5 g,its accuracy and repeatability can meet the testing requirements.Adding an appropriate amount of acid to the sample is beneficial for the dissolution of chloride ions from the iron oxide powder,but the type of acid added has no significant effect on the results.The results of chloride ion analysis are increased with the stirring time prolonged,but excessive stirring time can lead to poor repeatability of the analysis results.In summary,when the sample weight is 0.5 g,10 mL of 10%phosphoric acid is added,and the stirring time is 120 s,the precision and recovery rate of the analysis results meet production requirements.