含磷饲料中磷元素含量的EDXRF法测定

Determination of Phosphorus Content in Phosphorus-containing Feed by EDXRF Method

提出了一种应用能量色散X射线荧光光谱分析(EDXRF)法测定饲料中轻元素磷的方法。采用间接测量的方式,通过一系列化学反应将目标元素磷转换为磷钼酸喹啉沉淀,并对沉淀进行洗涤、过滤与干燥,应用EDXRF测定样品中的钼元素含量,最后根据生成物化学式中的磷元素与钼元素的化学关系计算得到磷元素的含量。对钼元素的最佳激发条件进行了探究,通过计算钼元素特征谱线峰背比,绘制其与激发条件的关系曲线,得到钼元素的最佳管电压为27 kV、最佳管电流为9μA、最佳测量时间为120 s。测量得出,含磷饲料中磷元素的质量分数为22.36%,相对标准偏差为0.46%,相对极差为0.24%,与熔片法(X射线荧光光谱分析)检测分析结果相一致。

A new method for the determination of light element phosphorus in feed by energy dispersive X-ray fluorescence(EDXRF)analysis was proposed.An indirect measurement was applied,and the target elemental phosphorus was converted into quinoline phosphomolybdate by a series of chemical reactions.After washing,filtration and drying,the content of molybdenum element in the sample was measured by EDXRF.And according to the relationship between the phosphorus element and the molybdenum element in the chemical products,the content of phosphorus can be calculated.The optimum determining conditions of molybdenum element were also investigated.By calculating the peak-to-back ratio of character line of molybdenum element,the relation curve was drawn.The optimal tube voltage of molybdenum element was 27 kV,the optimal tube current was 9μA,and the best measuring time was 120 s.In this experiment,the content of phosphorus in phosphorus-containing feed was 22.36%,the relative standard deviation was 0.46%,and the relative range was 0.24%.The consequence was in accord with the result of the melting method(X-ray fluorescence analysis).The analytical method of combination of physics and chemistry was put forward,some problems such as low detection efficiency and poor measurement accuracy were conquered,and the results showed that the experiment had good accuracy,stability and repeatability.The method provided a new way for measurement of phosphorus in feed,and showed good reference and directive significance for the determination of other light element content by EDXRF as well.