Itemized determination of As, Sb, Bi, Se, and Ge in graphite sample by HG-AFS with high-temperature microwave digestion

In this paper, we optimized a method for fast and accurate determination of five impurity elements (As, Sb, Bi, Se, and Ge) in graphite samples to overcome the shortcomings of existing methods, such as complicated equipment, cumbersome process, multiple-time preparation, separate determination, and large error in results. Graphite samples were digested with HNO₃–H₂SO₄–HClO₄–HF in a high-temperature and high-pressure microwave digestion apparatus, and the elements were extracted and determined separately by AFS (atomic fluorescence spectrometry). There is no element loss during the processing and analysis of this method. The spike recoveries (As: 90.30%–102.3%, Sb: 90.73%–110.0%, Bi: 90.00%–99.67%, Se: 93.33%–110.0%, Ge: 92.26%–104.2%) and precision (RSD%; As: 1.34%–8.96%, Sb: 2.67%–7.10%, Bi: 1.83%–4.58%, Se: 0.36%–3.25%, Ge: 4.41%–8.65%) meet the requirements of the corresponding quality specifications. The method has some advantages (such as no elemental loss, fast testing, strong element targeting, and accurate results), and thus can achieve batch determination of graphite samples. The optimized method for graphite sample and final solution preparations can be used for diverse spectrometric technologies, and that for spectrometer conditions have reference value for HG-AFS instruments.