X-ray Diffraction (XRD) and X-ray Structure Analysis
Polycrystalline and amorphous materials are analysed non-destructively using the X-ray Diffraction method (XRD). This method is based on the reflection of X-ray resulting from the interaction between X-rays and electrons of atoms. We are able to analyse two types of samples: solid samples and crystals.
X-RAY POWDER DIFFRACTION
For X-ray Powder Diffraction (XRPD), the solid sample is finely pulverized or crushed, and the resulting powder is analysed in a so-called powder diffractometer. A powder diffraction pattern is formed as a function of angle of incident X-ray beam and measured radiation intensity which is characteristic for each substance and acts as a unique "fingerprint". On the basis of obtained powder pattern, we are able to offer you following analyses:
The qualitative characterization of substances with X-ray Powder Diffraction is used in many areas, for example during production of chemicals, catalysts, pigments, building materials including quality control. The composition of an unknown sample or a mixture is identified by using a database with known compounds. The ICDD database applied by us and annually updated contains up to 300 thousand different inorganic compounds.
X-ray Powder Diffraction is also widely used in drug discovery for the characterization of polymorphism. One and the same substance can occur in various crystal forms (modifications, phases) by different arrangements of molecules. The polymorphic forms have an influence on solubility and stability of the substances by different physical and chemical properties. For this reason, pharmaceutical products from development to production process are analyzed for polymorphism using the XRPD method. Different polycrystalline structures of certain active substance are distinguished by unique powder pattern or compared with a sample determined as a reference. We can help you identify your polymorphic active ingredients and excipients including hydrates, solvates and amorphous forms, and provide XRPD analyzes even under regulated conditions such as GMP and according to monograph Ph. Eur. 2.9.33 or USP 941.
If a sample consists of several substances or phases, we are able to determine their respective content using standard-free Rietveld method. A theoretical powder pattern is calculated on the basis of the known crystal structure (requirement for the application of the method) and optimized with software until measured values correspond with the theory.
Apart from the phase analysis, X-ray Powder Diffraction additionally allows, for example in the case of catalysts, to determine crystallite sizes up to the nanometre range from the broadening of the peaks.
The use of X-ray Powder Diffraction is not limited to analysis of samples that are stable under normal environmental conditions. However, many substances may be present in various crystal forms depending on temperature, moisture content, etc. We have a sample chamber in which samples can be measured in a temperature range between -180 ° C and 400 ° C. In addition, it is possible to regulate relative humidity in the range of 5 to 95%, for example to detect phase conversions under different ambient conditions. The phase analysis on pharmaceutical samples can be performed under moisture, in air, in an inert gas or in a vacuum.
X-RAY STRUCTURE ANALYSIS
By X-ray Diffraction (XRD), crystals are also investigated to determine the atomic three-dimensional structure of a molecule by means of the specific reflection of the X-ray beam. The requirement for this analysis is the presence of a single crystal which is generated by varying different conditions (temperature, solvent, evaporation rate, etc.).
We offer you a complete service package for the X-ray structure analysis of "small" organic molecules including crystallization, crystal selection and measurement up to the finished molecular and crystal structure. Our results form the basis for development and admission of active ingredients and pharmaceutical products. Optionally, the absolute configuration of the molecule can be determined.