含亚磷酸钾的水溶肥中总磷含量的测定

Determination of Total Phosphorus in Water Soluble Fertilizer Containing Potassium Phosphate

喹钼柠酮重量法是目前测定水溶肥中总磷含量的通用方法。由于亚磷酸不能与喹钼柠酮试剂定量地生成沉淀,因此含亚磷酸的水溶肥不能采用喹钼柠酮试剂的方法直接测定总磷含量。为了解决这一问题,本研究采用王水氧化预处理含亚磷酸钾的水溶肥样品,将亚磷酸氧化成正磷酸,再用传统的喹钼柠酮试剂测定总磷含量。实验结果表明,本测定方法数据准确,误差小,操作简单可行。

Quinomolimone gravimetric method was a general method for the determination of total phosphorus content in watersoluble fertilizers. Because phosphite could not form precipitate quantitatively with quinomolykinone, so the water-soluble fertilizer containing phosphite could not be directly determined with quinomolykinone reagent. In this experiment, aqua regia was used to pretreat water-soluble fertilizer samples contained potassium phosphite in order to oxidize phosphorous acid to orthophosphoric acid, and then the total phosphorus content was determined with traditional quinomolybdate citrate reagent. The experimental data showed that the method had high accuracy and small error.