Determination Of Phosphorus Content In Phosphorus-Containing Feed By EDXRF Method

With the development of livestock breeding industry in China,biological feed technology has been highly valued.As one of the essential mineral elements for animals,the phosphorus in feed affects the growth and reproduction ability of poultry.On the other hand,excessive phosphorus flowing into the water will cause high phosphorus levels in the water body and further cause a series of ecological and environmental issues,such as water pollution.Therefore,analysis and determination of phosphorus content in livestock and poultry feed is vitally important to improve the efficiency of breeding and environment.X-ray fluorescence analysis technology is an important detection method for quantitative and qualitative analysis of substances.Among them,energy dispersive X-ray fluorescence analysis(EDXRF)is widely used in metallurgy,industrial and agricultural production,analysis of geological samples,and analysis of archeological relics due to its high analysis accuracy,short analysis time,and good instrument stability.Currently,there are many different kinds of methods for the phosphorus content,including phosphorus molybdic quinoline weight and capacity methods,phosphomolybdenum blue colorimetric method,near infrared spectroscopy,and EDXRF.Compared with other methods,EDXRF has the characteristics of wide measurement range,simple measurement method and accurate measurement results.However,in the determination of light elements,the EDXRF fluorescence yield and detection efficiency are low.Meanwhile,the energy between the K-line of other light elements is close,which causes problems such as absorption-enhancement and overlap between the lines.Therefore,EDXRF has a greater limitation in the determination of light elemental phosphorus.In view of the above problems,a new method for the determination of phosphorus in phosphorous feed by EDXRF was proposed.the way of EDXRF combined with chemical conversion was applied,Phosphorus was first converted by chemical reactions into deposits containing molybdenum,after washing,filtering drying and other steps,the precipitation samples was made into sheets by pressing,and sheets were placed on the spectrometer,analysis of molybdenum elements content of determination,eventually by the resultant precipitation of phosphorus and molybdenum stoichiometric relation assumptions of phosphorus content in the samples.In addition,the paper also determined the optimal excitation condition of molybdenum element K_?spectrum peak,and obtained the relationship curve with the tube voltage,current and measurement time from the peak-to-back ratio of molybdenum element K_?spectrum peak.Finally,the optimum excitation coditions of molybdenum:tube voltage was 27kV,measurement time was 120s and tube current was 9?A.By using this method,the total phosphorus content in phosphorous feed was22.36%,of which the relative standard deviation and the range were 0.46%and o24%,respectively.It is shown that the phosphorus element measurement method described in this paper has high precision and high repeatability,which provides a new solution for the determination of other light elements with EDXRF.In addition,this article studies the total reflection X-ray fluorescence analysis(TXRF),and briefly introduces the TXRF technology from the aspects of experimental principles,development status,selection of experimental instruments and advantages.This paper also made a preliminary construction of this instrument,preparations have been made for the future use of TXRF technology to determine the composition of substances.