The electromagnetic spectrum contributes immensely to our understanding of the nature of matter. Different segments of the electromagnetic spectrum interact differently with the constituents of matter and yield a wealth of information to the analytical scientist.
X-rays have a unique property of penetrating the inner layers of matter and each atomic plane results in a diffraction pattern. The combination of such unique diffraction patterns yields the character characteristic pattern that helps characterize the material under investigation.Such behaviour of x-rays provides a useful tool to understand the arrangement of atoms in crystalsand inter-planar distances in the Single crystal XRD analysis mode. In the Powder XRD mode it helps characterize semi-crystalline materials based on their unique diffraction patterns.Such details provided by XRDare put to use in characterization of materials in a number of application areas such as minerals, pharmaceuticals, foods, polymers, electronic component materials and materials under forensic investigations. Today major advancements are coming up in the area of nanotechnology and its study yields valuable information on nano materials as well.
The article explores some potential applications of XRD in typical areas of application.
The biggest advantage of XRD is that it is nondestructive technique requiring minimal sample preparation.The same sample can be used subsequently for other confirmatory studies. A drug compound can be available in several formulations depending on the specific medical administration requirements. XRD provides valuable details during different stages of new drug development, manufacturing and on composition of finished formulations. Such information contributes significantly in manufacturing formulations with the right proportion of active ingredients and excipients to give the desired properties such as dissolution rate, friability and long-term stability of solid dosage forms.
The variable temperature accessory helps establish the role of temperature and humidity on stability of finished products under different climatic zones. The amorphous content present tends to transform into crystalline state during long-term storage due to environmental changes. XRD provides useful details on degree of amorphous content under any set of conditions. Further the degradation products and excipients play a decisive role on the effectiveness of the active ingredient .XRD studies yield in addition useful information on polymorphism of different constituentsin drug formulations.
Nano particles are the basic building blocks of many engineering materials, cosmetic powders, food additives, polymers, pharmaceuticals and composites. The size distribution of nanoparticles affects features and be havioural characteristics of the materials. XRD provides valuable details in development of new materials with desired properties and applications.
The current trend in miniaturization of electronic integrated circuits requires materials with special conducting properties. XRD proves to be a useful tool in characterization of crystal structures and defects in manufacturing of microelectronic components.
Cosmetic products are a mix of organic and inorganic compounds which can in addition to their cosmetic features also exhibit toxic effects due to skin permeability. Cosmetic products come as powders, creams, gels, lotions, etc and several analytical approaches have been used to identify and characterize the components. XRD has again proved to be a versatile tool in its application of cosmetic components with crystalline or semi- crystalline properties.
XRD is a valuable tool for grading of minerals for commercial purposes. Even such characterization is necessary for deciding commercial viability of mining operations.
Rock dynamics leads to stress in the rock formations which is evident at the crystal structure level.XRD is helpful in determining the stress induced crystal deformities and weathering changes of exposed mineral bearing rocks.
Synthetic foods contain several additives such as colouring matters, sweetners, flavouring agents, anti-oxidants, stabilizers, etc. These materials are added during manufacturing process to get the desired taste, aroma and texture of synthetic foods. XRD is once again useful for characterization of food additives along with other analytical techniques.
XRD is a useful tool in investigation of samples collected from scene of crime. These include materials such as paint chips, broken glass, narcotic powders, explosive powder residues, etc. Such examination can help trace the origin which serves to nail down the suspects behind the crime.
The application areas of XRD are growing at an impressive pace and complement other material characterization techniques such as FT -IR. Thermal analysis and Raman spectroscopy.