电感耦合等离子体质谱测定饲料中稀土元素镧和铈的研究

研究建立了应用电感耦合等离子体质谱(ICP-MS)同时测定饲料中稀土元素镧(La)和铈(Ce)的方法。优化了ICP-MS的操作条件，通过基体加入法和基体逐级稀释法研究了预混合饲料和配合饲料基体对La和Ce测定的影响，考察了硝酸浓度对La和Ce响应信号的抑制作用。在优化的条件下，以In(115)和Tb(159)为内标物，La和Ce检出限分别为26.2和6.47 ng·kg-1,线性相关系数为1.0000，动态线性范围达到3个数量级。将该方法用于预混合饲料和配合饲料样品中稀土元素La和Ce的测定，其回收率≥77.8%，相对标准偏差(RSD)≤8.5%，结果令人满意。

Study on Determination of Rare Earth La and Ce in Feed by Using ICP-MS

An advanced method for the determination of rare earth La and Ce in animal feed by using of inductively coupled plasma mass spectrometry was studied. The operation parameters for ICP-MS was optimized, the effect of pre-mix feed matrix and formular feed matrix for La and Ce was studied by the conventional method and stepwise dilution method, and the suppression of signal intensity of La and Ce by nitric acid was examined. Under the optimum condition, the limit of determination for La and Ce were 2.62 x 10(-2) microg x kg(-1) and 6.47 x 10(-3) microg x kg(-1), respectively, the linear coefficient was 1.000 0, the dynamical linear range was of 3 order of magnitudes, and the internal standards were In(115) and Tb(159). The developed method was applied to the determination of rare earth La and Ce in pre-mix feed and formular feed, with the recovery > or = 77.8% and the relative standard deviation(RSD) < or = 8.5%, and the testing results were satisfactory.