化肥标准物质中钾含量准确定值方法研究

摘要

A method combined with potassium tetraphenylborate gravimetric analysis and ion chromatography is adopted to measure the content of potassium in potassium sulphate which is one of the fertilizer reference materials.The content of sodium in the precipitate and the content of potassium in the residues and filtrates are measured by ion chromatography.The effects of the gravimetric method are analyzed including buoyancy correction,insolubles,residues,filtrates and sodium content contained in the precipitation.Updated by the analysis,the influencing factors are reduced to the minimum.The reference material of potassium sulfate is reproduced and measured with this method.The potassium content is 44.69％,the expanded uncertainty is 0.17％ (k =2)and the uniformity and stability are both met the requirement.And its traceability is guaranteed.%采用四苯硼酸钾重量法与离子色谱相结合法对化肥标准物质硫酸钾中的钾含量进行了定值.使用离子色谱仪对重量法测量过程中的沉淀残留、滤液中钾含量及四苯硼酸钾沉淀物包夹钠含量进行了测定,同时对四苯硼酸钾重量法各个环节的称量浮力修正、样品的不溶物、沉淀残留、滤液和包夹等影响进行了系统分析.并对重量法测定结果进行了修正,将各影响量降到了最低水平.用该方法对硫酸钾标准物质进行了复制和准确定值,其中钾含量为44.69％,扩展不确定度为0.17％(k=2),均匀性和稳定性均符合要求,保证了量值溯源的可靠性.