Applications of XRD
X-ray diffraction (XRD) can be used to unambiguously characterize the composition of pharmaceuticals. An XRD-pattern is a direct result of the crystal structures, which are present in the pharmaceutical under study. As such, the parameters typically associated with crystal structure can be simply accessed. For example, once an active drug has been isolated, an indexed X-ray powder diffraction pattern is required to analyse the crystal structure, secure a patent and protect the company’s investment.
For multi-component formulations, the actual percentages of the active ingredients in the final dosage form can be accurately analysed in situ, along with the percentage of any amorphous packing ingredients used.
XRD is the key technique for solid-state drug analysis, benefiting all stages of drug development, testing and production.
XRD is used mainly in contact trace analysis. Examples of contact traces are paint flakes, hair, glass fragments, stains of any description and loose powdered materials. Identification and comparison of trace quantities of material can help in the conviction or exoneration of a person suspected of involvement in a crime.
XRD is the key tool in mineral exploration. Mineralogists have been amongst the foremost to develop and promote the new field of X-ray crystallography after its discovery. Thus, the advent of XRD has literally revolutionized the geological sciences to such a degree that they have become unthinkable without this tool. Nowadays, any geological group actively involved in mineralogical studies would be lost without XRD to unambiguously characterise the individual crystal structures. Each mineral type is defined by a characteristic crystal structure, which will give a unique x-ray diffraction pattern, allowing rapid identification of minerals present within a rock or soil sample. The XRD data can be analysed to determine the proportion of the different minerals present.
As the microelectronics industry uses silicon and gallium arsenide single crystal substrates in integrated circuit production, there is a need to fully characterise these materials using the XRD. XRD topography can easily detect and image the presence of defects within a crystal, making it a powerful non-destructive evaluation tool for characterising industrially important single crystal specimens.
While glasses are X-ray amorphous and do not themselves give X-ray diffraction patterns, there are still manifold uses of XRD in the glass industry. They include identification of crystalline particles which cause tiny faults in bulk glass, and measurements of crystalline coatings for texture, crystallite size and crystallinity.