K金饰品中金含量的检测方法比对

Comparison of Detection Methods for Gold Content in Gold Jewelry

目前实验室对金首饰金含量的主要检测方法为火试金法、X射线荧光光谱(XRF)法和电感耦合等离子体-原子发射光谱(ICP-AES)法.当测试结果出现争议时,国家标准GB 11887-2012中以火试金法作为仲裁方法.采用上述3种不同的金含量测试方法分别对14K、18K和22K饰品的金含量进行测定,并对3种方法检测结果进行比对.结果发现,在3种方法均可满足样品分析对准确度的要求时,以火试金法为基准,XRF法与ICP-AES法对同纯度的金首饰检测结果的相对误差差异较大,XRF法的结果可满足检测要求,而ICP-AES法的结果无法满足检测要求.其中,XRF法的相对误差为0.05%～0.77%,ICP-AES法的相对误差为1.24%～3.89%.从结果来看,低纯度的K金饰品使用XRF法的检测结果要更接近于火试金法.

At present,testing methods for gold content in gold jewelry are mainly fire assaying method,X ray fluorescence(XRF)and inductively coupled plasma-atomic emission spectrometry(ICP-AES).When there are disagreements in the testing results,fire assaying method is the arbitral method.In this paper,the gold contents of 14K,18K and 22K gold samples were determined by the three different methods,and the results were compared and analyzed.The results showed that,under the conditions that the three methods met the accuracy requirement of sample analysis,and using the fire assaying method as the criterion,then the relative errors were quite different in the results of determing the same purity of gold by XRF and ICP-AES.The results of the XRF method can meet the testing requirements,while that of the ICP-AES method can not.The relative error of XRF method was 0.05%~0.77%,and that of the ICP-AES method was 1.24%~3.89%.From the results,the test results of low purity precious metal jewelry using XRF method were closer to the fire assay method.