自动电位滴定法测定115%以下多聚磷酸中的磷酸含量

Determination of Phosphoric Acid Content in Polyphosphoric Acid below 115%by Automatic Potentiometric Titration

将115%以下的聚磷酸加热水解成正磷酸,用已知浓度的氢氧化钠标准滴定溶液在全自动电位滴定仪上进行滴定,用自动电位滴定仪记录滴定曲线,根据曲线上的2个拐点处所消耗的氢氧化钠标准滴定溶液的体积,计算出聚磷酸中磷酸的含量。该方法与重量法相比,具有分析过程简单、快速、准确度高、成本低的优点。

In this method,the polyphosphate less than 115%is heated and hydrolyzed into positive phosphoric acid,the standard titration solution of sodium hydroxide with known concentration is titrated on the automatic potentiometric titrator,and the titration curve is recorded by the automatic potentiometric titrator and the phosphoric acid content is calculated according to the volume of sodium hydroxide consumed at the two inflection points on the curve.Compared with gravimetric method,this method has the advantages of simple analysis process,rapid analysis,high accuracy and low cost.