Analysis Of Light Elements Potassium And Sodium Based On EDXRF Method

Potassium is an essential element in plants,which determines the growth,development and yield of crops.As an important nutrient element in fertilizer,potassium is not only an important index to evaluate fertilizer quality,but also one of the important causes of soil and water pollution.Therefore,accurate determination of potassium content in fertilizer is beneficial to correct use of fertilizer and reduce potassium pollution.As an important component of animal tissue fluid,the supplement of sodium affects appetite and metabolism of livestock and poultry.It is important to measure the content of sodium in the diet and sodium additive of livestock and poultry to raise the output value of livestock and poultry industry scientifically.X-ray fluorescence analysis（XRF）is a mature and accurate analytical technology,which is developing rapidly and becoming more and more functional,miniaturized,intelligent and domestic.It is widely used in archaeological,metallurgical,environmental,geological analysis and other industrial and agricultural qualitative and quantitative analysis.Energy dispersive X-ray fluorescence analysis（EDXRF）is widely used in the analytical field due to its advantages of rapid analysis,accurate measurement and simple operation.However,in the direct measurement of light elements（Z≤20）,EDXRF has low resolution and accuracy in the measurement of light elements potassium and sodium due to its low excitation efficiency,low detection efficiency,close spectral energy and serious matrix effect.In view of the above problems,a new method based on EDXRF technology to measure the content of potassium in potash fertilizer and sodium in feed additives was proposed in this paper.By EDXRF and chemical conversion method,potassium in potash fertilizer and sodium in feed additive were firstly transformed into precipitation containing silver and iron by chemical treatment,respectively.After filtration,washing and drying,the precipitates were pressed,and the contents of silver and iron were measured by EDXRF spectrometer.Finally,the contents of potassium and sodium in the samples were calculated according to the quantitative relationship between silver and potassium,iron and sodium in the chemical reaction.In addition,the optimum measuring conditions of Kα characteristic peaks of intermediate measuring elements silver and iron are analyzed.The best measuring tube voltage of silver is 30 k V,and the best measuring tube current is 11μA.The best measuring voltage of iron element tube is 25 k V and the best measuring current is 11μA.Under the optimal measurement conditions,the standard curves of silver and iron were drawn respectively,and the content of potassium in potash fertilizer was 30.25%,and that of sodium in feed additive was 39.05%,with relative standard deviations of0.41% and 0.32%,respectively.In addition,the stability and accuracy of this method were proved by repeatability test,comparison test and recovery test,providing a new solution for the determination of other light elements by EDXRF.