X射线荧光光谱法测定黄金首饰金含量不确定度的评定

The Uncertainty Evaluation of Gold Content in Gold Jewelry by X-ray Fluorescence Spectrometry

黄金首饰的表层元素经X射线激发,发射出特征X射线荧光能量光谱线。不同元素的能量光谱线与其含量存在着特定的线性关系。能量色散X射线荧光光谱仪通过采用脉冲高度分析器和配套的相关软件将不同能量的脉冲分开,找出相应的元素,测量相应元素的具体含量值。通过X射线荧光光谱仪对黄金首饰的金含量测出的一系列测量值,依据GB/T18043-2013对黄金首饰样品金含量的不确定度进行计算。对采用的黄金标准物质运用最小二乘法建立数学模型,以标准值为x,3次测量值的平均值为y,找出线性关系方程。通过标准物质的运用,当置信因子k=2时,最终分别计算出18K金样品、足金样品金含量的扩展不确定度。

The surface element of gold jewelry is excited by X ray to emit the characteristic X ray fluorescence energy spectrum line. There is a linear relationship between the energy spectrum and the content of different elements. The energy dispersive X ray fluorescence spectrometer uses the pulse height analyzer and the related software to separate the pulse of different energy to find the corresponding element and measure the specific content of the corresponding element. This paper calculates the uncertainty of gold content in gold jewelry samples by means of a series of measured values of gold content in gold jewelry by X ray fluorescence spectrometer based on GB/T 18043-2013, establishes the mathematical model by using the least squares method with standard value x and the average value y of three measurements to find the linear equation, and finally calculates the extended uncertainty of gold content in 18 karat gold samples and pure gold samples respectively when the confidence factor is 2 through the use of standard materials.