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Validation of Powder X-Ray Diffraction Following EN ISO/IEC 17025

NCJ Number
Journal of Forensic Sciences Volume: 57 Issue: 3 Dated: May 2012 Pages: 722-737
Regina Eckardt, Dipl.-Min.; Erik Krupicka, Ph.D.; Wolfgang Hofmeister, Ph.D.
Date Published
May 2012
16 pages
This paper discusses the topic of validation and powder X-ray diffraction (PXRD).
Powder X-ray diffraction (PXRD) is used widely in forensic science laboratories with the main focus of qualitative phase identification. Little is found in literature referring to the topic of validation of PXRD in the field of forensic sciences. According to EN ISO/IEC 17025, the method has to be tested for several parameters. Trueness, specificity, and selectivity of PXRD were tested using certified reference materials or a combination thereof. All three tested parameters showed the secure performance of the method. Sample preparation errors were simulated to evaluate the robustness of the method. These errors were either easily detected by the operator or nonsignificant for phase identification. In case of the detection limit, a statistical evaluation of the signal-to-noise ratio showed that a peak criterion of three sigma is inadequate and recommendations for a more realistic peak criterion are given. Finally, the results of an international proficiency test showed the secure performance of PXRD. Abstract published by arrangement with John Wiley & Sons.