Abstract: 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.
Eckardt, Regina; Krupicka, Erik; Hofmeister, Wolfgang
The mechanism by which small molecules assemble into microscale tubular structures in aqueous solution remains poorly understood, particularly when the initial building blocks are non‐amphiphilic molecules and no surfactant is used. It is here shown how a subnanometric molecule ... more
The image illustrates a natural phenomenon of droplet formation caused by the condensation of vapor on a nonwettable surface at temperature below the dew point. Real‐time observing the light scattered from the droplets may lead to a new mechanism for vapor sensing. However, the dew point ... more
NO is a key vasodilator in mammalian cardiovascular systems and has been shown to sensitize tissue to γ‐radiation. However, photochemical NO precursors that can be activated by these NIR wavelengths are extremely limited. G. D. Stucky, D. Zhao, P. C. Ford, F. Zhang and co‐workers have ad ... more
A team of pioneering South Korean scientists have succeeded in producing the polymers used for everyday plastics through bioengineering, rather than through the use of fossil fuel based chemicals. This groundbreaking research, which may now allow for the production of environmentally consci ... more
In the past, restoration of paintings and other old artwork often involved application of acrylic resins to consolidate and protect them. One of the most important tasks for modern restorers is thus to remove these layers, because it turns out that acrylic resins not only drastically change ... more
Converting the trash that fills the world's landfills into biofuel may be the answer to both the growing energy crisis and to tackling carbon emissions, claim scientists in Singapore and Switzerland. New research published in Global Change Biology: Bioenergy, reveals how replacing gasoline ... more