Quantitative Phase Analysis by the Rietveld Method for Forensic Science |
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| Authors: | Fei Deng Ph.D. Xiaodong Lin M.L. Yonghong He Ph.D. Shu Li M.L. Run Zi B.Sc. Shijun Lai B.E. |
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| Affiliation: | 1. Graduate School at Shenzhen, Tsinghua University, Shenzhen, China;2. Research Institution of Forensic Science and Technology, Shenzhen Police Bureau, Shenzhen, China;3. Shenzhen Key Laboratory of Special Functional Materials, Shenzhen, China |
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| Abstract: | Quantitative phase analysis (QPA) is helpful to determine the type attribute of the object because it could present the content of the constituents. QPA by Rietveld method requires neither measurement of calibration data nor the use of an internal standard; however, the approximate crystal structure of each phase in a mixture is necessary. In this study, 8 synthetic mixtures composed of potassium nitrate and sulfur were analyzed by Rietveld QPA method. The Rietveld refinement was accomplished with a material analysis using diffraction program and evaluated by three agreement indices. Results showed that Rietveld QPA yielded precise results, with errors generally less than 2.0% absolute. In addition, a criminal case which was broken successfully with the help of Rietveld QPA method was also introduced. This method will allow forensic investigators to acquire detailed information of the material evidence, which could point out the direction for case detection and court proceedings. |
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| Keywords: | forensic science material evidence quantitative phase analysis powder X‐ray diffraction whole pattern fitting Rietveld method |
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