EDXRF法测量饲料添加剂中钠元素含量

Quantitative detection of sodium content in feed additive sodium chloride based on EDXRF method

钠元素是动物体内代谢所必需的矿物质元素,在畜牧业养殖中主要以饲料添加剂的形式提供,适当的钠元素含量对畜牧业养殖安全和效益产值都具有重要意义,但是目前缺乏简便快捷的有效分析方法。利用能量色散X射线荧光光谱仪(Energy Dispersive X-ray Fluorescence,EDXRF)开展饲料盐中的钠元素含量测定研究。首先通过化学反应将样品中的钠元素完全转化为氟铁铵钠沉淀,利用EDXRF分析测定沉淀中铁元素的含量,再根据氟铁铵钠化学式中铁和钠的关系,计算出钠的含量。最后通过铁元素特征峰峰背比与激发条件的关系曲线,确定铁元素的最佳激发条件,获得最佳光管电压为25 kV,最佳光管电流为11μA。测量结果的钠含量为39.02%,相对平均偏差0.27%,相对标准偏差0.32%。该方法具有重复性好、可操作性强等特点,提供了一种全新的饲料添加剂氯化钠中钠元素的检测分析方案。

[Background] Sodium is one of the essential mineral elements necessary for metabolism in all animals.It is very important to accurately detect sodium content in feed additive for livestock and poultry breeding, which can greatly enhance the added value of farm-raising production. [Purpose] This study aims to propose a new method for measuring the content of sodium in feed additives by energy dispersive X-ray fluorescence(EDXRF) analysis.[Methods] The method combined chemical methods with EDXRF to accurately detect the content of sodium in feed additive sodium chloride. Firstly, samples were treated to prepare test samples and standard samples, respectively. By means of chemical reaction, the content of sodium element in the sample was completely converted into iron element,and then precipitated. Secondly, based on the process, a group of standard samples with different iron contents were prepared to seek the net area of characteristic peaks of iron element for EDXRF analysis. The relation curve between iron content and the net area of characteristic peak was found and served as the standard curve. Then the net area of characteristic iron peaks in the test samples were measured by EDXRF. The measured values were substituted into the standard curve to obtain the iron content in the precipitation. The sodium content in the sample was determined by the precipitation mass, the iron content in the precipitation and the relationship between iron element and sodium element in the product precipitation. Finally, the best excitation conditions of iron element were determined by relationship curve between characteristic peak-to-back ratio of iron element and excitation conditions. [Results]Obtained optimum tube voltage and current for best excitation conditions of iron element are 25 k V and 11 μA,respectively. The measuring accuracy of sodium content in feed additive sodium chloride is 39.02% with relative average deviation of 0.27% and relative standard deviation of 0.32%. [Conclusions] The measured results are basically in good agreement with that obtained by wavelength dispersive X-ray fluorescence. Proposed method in this study for the determination of sodium in feed additive sodium chloride has the characteristics of good repeatability and strong operability, providing a new method for the determination and analysis of sodium in feed additive sodium chloride.