电感耦合等离子体发射光谱法测定配合饲料中锰含量的不确定度评定

Evaluation of Uncertainty for Manganese Determination in Formula Feed by Inductively Coupled Plasma Optical Emission Spectrometry

研究旨在建立电感耦合等离子体发射光谱法(inductively coupled plasma optical emission spectroscopy,ICP-OES)测定饲料中锰的不确定度评定方法。样品经微波消解,将一定量的样品消解液注入ICP-OES仪器中,采用标准曲线法定量。分析了测定过程中的不确定度来源,对不确定度的组成进行评定和量化。根据数学模型计算了样品中锰的含量,合成标准不确定度和扩展不确定度。结果表明,ICP-OES测定饲料中锰的含量为508 mg/kg,扩展不确定度为46 mg/kg(k=2),结果表达为(508±46) mg/kg(k=2)。分析过程显示,不确定度的主要来源是加标回收试验,其次是样品溶液中锰浓度的测定和重复试验,其他因素引起的不确定度可以忽略。

The purpose of this study is to establish an uncertainty evaluation method for determination of manganese in formula feed by inductively coupled plasma optical emission spectrometry(ICP-OES).After the sample was digested by microwave,a certain amount of sample digestion solution was injected into the ICP-OES instrument,and the standard curve method was used for quantitative determination.The sources of uncertainty in the process of determination were analyzed,and the components of uncertainty were evaluated and quantified.The content of manganese in the sample was calculated according to the mathematical model.The synthetic standard uncertainty and the extended uncertainty were calculated.The results showed that the content of manganese in the sample was 508 mg/kg by ICP-OES.The expanded uncertainty was 46 mg/kg(k=2),and the result was expressed as(508±46)mg/kg(k=2).Analysis process displayed that the standard recovery of the sample was the main source of uncertainty,followed by determination of manganese concentration in the sample solution and the repeated determination,respectively.The uncertainty caused by other factors could be ignored.