X射线荧光光谱法与灰吹法测定K金首饰金含量比较

Gold Content in Gold Alloy Products Analyzed by X-ray Fluorescence (XRF) and Cupellation: A Comparison Study

  • 摘要: 为检测首饰产品中的金含量,比较了25件样品,它们分别是足金5件、黄色和白色18K金各5件,黄色和白色14K金各5件。利用X射线荧光光谱(XRF)法和灰吹法分析了样品的含金量。在足金样品分析中,金含量为999‰、990‰以上的样品经两种方法的检测出现1.23‰的微小差别。而金含量为990‰样品经两种检测方法的差别是4.5‰;黄色和白色18K金样品经两种方法的检测差别分别是6.4‰和13.1‰;黄色和白色14K金样品经两种方法的检测差别分别是18.2‰和16.5‰。结果显示,用XRF检测金合金时,随着金含量降低,检测差别增大,白色K金的分析数据分布范围大于黄色K金。因此,XRF适用于金含量为999‰以上的产品,对于金含量为999‰以下的产品来说,灰吹法比XRF法更适合。

     

    Abstract: In this research, the possibility of gold content in gold products manufactured and distributed fall short of standards due to inadequate analysis has been studied. Total 25 samples (5 samples each sold as 24K gold, 18K yellow gold and white gold, and 14K yellow gold and white gold) were prepared, and the gold content in each sample was analyzed by two different methods:XRF (5 runs per sample) widely used in manufacturing industry and cupellation designated as standard procedure usually. In 24K gold sample, the difference between two analytic methods for gold content above 999‰ was determined as 1.23‰, which is relatively small. However, the difference in Au990 products became greater and was found to be 4.5‰. In 18K gold samples, the difference became even greater, and difference for yellow gold and white gold were 6.4‰ and 13.1‰, respectively. Likewise, differences in 14K yellow gold and white gold were 18.2‰ and 16.5‰, respectively. From above results, it can be concluded that difference in XRF analysis becomes greater when gold content is smaller and that data scattering in white gold that contains nickel alloy element is greater than that in yellow gold. Therefore, XRF should only be used for gold content above 999‰ for qualitatively analysis of gold content, and results on products with gold content below 999‰ are not reliable. We conclude that cupellation is a more suited method for quality control of gold content than XRF.

     

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