QUALX2.0 is the new version of QUALX, a computer program for qualitative phase analysis by powder diffraction data. The previous version of QUALX was able to carry out phase identification by ...querying the PDF‐2 commercial database. The main novelty of QUALX2.0 is the possibility of querying also a freely available database, POW_COD. POW_COD has been built up by starting from the structure information contained in the Crystallography Open Database (COD). The latter is a growing collection of diffraction data, freely downloadable from the web, corresponding to inorganic, metal–organic, organic and mineral structures. QUALX2.0 retains the main capabilities of the previous version: (a) automatically estimating and subtracting the background; (b) locating the experimental diffraction peaks; (c) searching the database for single‐phase pattern(s) best matching to the experimental powder diffraction data; (d) taking into account suitable restraints in the search; (e) performing a semi‐quantitative analysis; (f) enabling the change of default choices and strategies via a user‐friendly graphic interface. The advances of QUALX2.0 with respect to QUALX include (i) a wider variety of types of importable ASCII file containing the experimental diffraction pattern and (ii) new search–match options. The program, written in Fortran and C++, runs on PCs under the Windows operating system. The POW_COD database is exported in SQLite3 format.
iQual is a new computer program developed for qualitative phase analysis using powder diffraction data. It is based on a new database named Crystal_db, derived from the latest Crystallography Open ...Database. Crystal_db has been created with organized functional modules and optimized index structures, greatly enhancing the database's search efficiency. The iQual program offers users a wide range of querying capabilities and convenient visualization features. In addition to providing an efficient interactive interface, the program combines with the optimized database to enable efficient searching for and finding of the data entries that best match the experimental data for qualitative analysis of X‐ray diffraction patterns. The highlight of this search–match method lies in an effective two‐step approach that makes full use of the database structure. A preliminary screening is adopted, based on the five strongest diffraction peaks of each candidate phase, prior to scoring the candidate phases. Matrix operations in both screening and scoring processes enhance the program's efficiency.
iQual is a computer program that utilizes the optimized Crystal_db database, derived from the Crystallography Open Database, for efficient searching and matching of experimental X‐ray diffraction patterns for qualitative phase analysis, employing a two‐step approach and matrix operations for enhanced efficiency.
X-ray powder diffraction (XRPD) and thermal analysis (differential scanning calorimetry/derivative of thermogravimetry (DSC/DTG)) are solid-state techniques that can be successfully used to identify ...and quantify various chemical compounds in polycrystalline mixtures, such as dietary supplements or drugs. In this work, 31 dietary supplements available on the Polish market that contain iron compounds, namely iron gluconate, fumarate, bisglycinate, citrate and pyrophosphate, were evaluated. The aim of the work was to identify iron compounds declared by the manufacturer as food supplements and to try to verify compliance with the manufacturer's claims. Studies performed by X-ray and thermal analysis confirmed that crystalline iron compounds (iron (II) gluconate, iron (II) fumarate), declared by the manufacturers, were present in the investigated dietary supplements. Iron (II) bisglycinate proved to be semi-crystalline. However, depending on the composition of the formulation, it was possible to identify this compound in the tested supplements. For amorphous iron compounds (iron (III) citrate and iron (III) pyrophosphate), the diffraction pattern does not have characteristic diffraction lines. Food supplements containing crystalline iron compounds have a melting point close to the melting point of pure iron compounds. The presence of excipients was found to affect the shapes and positions of the endothermic peaks significantly. Widening of endothermic peaks and changes in their position were observed, as well as exothermic peaks indicating crystallization of amorphous compounds. Weight loss was determined for all dietary supplements tested. Analysis of the DTG curves showed that the thermal decomposition of most food supplements takes place in several steps. The results obtained by a combination of both simple, relatively fast and reliable XRPD and DSC/DTG methods are helpful in determining phase composition, pharmaceutical abnormalities or by detecting the presence of the correct polymorphic form.
The main objective of the presented preliminary study was the identification of iron-containing phases. Iron-containing phases had accumulated in organic topsoil horizons collected from an area that ...has long been affected by the steel industry and emissions from power plants. X-ray diffraction and Mössbauer spectroscopy methods were used for the determination of the iron-containing mineral phases in topsoil subsamples which, after two-staged separation, varied in terms of magnetic susceptibility and granulometry. The Mössbauer spectra were recorded using paramagnetic and magnetic components, although the latter occurred only in the strongly magnetic fraction. The central part of spectra was fitted by two doublets (D1 and D2), which were identified as aluminosilicates. Simultaneously, the experimental spectra were described using several Zeeman sextets (Z1, Z2, and Z3) corresponding to the occurrence of hematite and magnetite-like phases with iron in tetrahedral and octahedral sites. Identification of magnetic phases in the tested material, including hematite, led to the conclusion that soil contamination in the studied area was presumably caused by emissions from a nearby power plant. Magnetite-like phases with a different iron content detected in topsoil samples could be related to metallurgical and coking processes, reflecting the specificity of the industrial area from which the samples were taken. The specific composition of the iron-containing aluminosilicates also illustrated the intense and long-lasting impact of the steel and coking industries on the studied area.
An attempt was made to determine phase composition of commercial aluminium alloys using X-ray diffraction. Samples for phase composition analysis were selected from the group of aluminium alloys ...covered by the EN 573-3:2013 standard 1. Representative samples were taken from eight groups of alloys with different chemical composition (at least one sample from each group). The diffraction intensity was measured with a standard X-ray diffractometer in Bragg-Brentano geometry in a way that allowed identification of the weakest diffraction peaks. As a results of the performed research it has been shown that X-ray phase analysis can be used to identify the matrix of aluminium alloys, Si and crystalline intermetallic phases such as Mg2Si, Al93.38Cu6.02Fe24Si16.27, Al4.01MnSi0.74, MgZn2, Al17(Fe3.2Mn0.8)Si2, Al65Cu20Fe15, and Cu3Mn2Al. The detectability limit of the above-mentioned phases is better than 0.5%. The research has also shown that X-ray phase analysis is applicable in the investigation of phase transformations taking place in aluminium alloys.
The phase identification of a polycrystalline mixture by X-ray powder diffraction data is often requested for studying materials interesting to different scientific and technological fields: ...chemistry, pharmaceutics, mineralogy, archeometry, forensic science, etc. The availability of user friendly computer programs, able to carry out qualitative phase analysis in efficient and possibly automatic way, is extremely useful to the scientific community involved in powder diffraction. QUALX2.0, the evolution of QUALX, is a freely distributed software for qualitative phase analysis. Based on the traditional search–match method, it is able to manage both a commercial database (PDF-2 maintained by ICDD), and a freely available database (POW_COD generated by the structure information contained in the Crystallography Open Database). QUALX2.0 is continuously improved in terms of computing and graphic tools. Correspondingly, the database POW_COD is suitably modified to make efficient the operations of search. The search–match approach can be facilitated by the use of restraints, when available, involving the chemical composition, the kind of compound(s) (e.g., organic, inorganic, etc.), the symmetry (space group, crystal system), the unit-cell parameters and/or volume, the crystal properties (measured and/or calculated crystal density, crystal color). An outline of the main features of QUALX2.0 and an example of application is described.
The main purpose of this study was to identify the mineral composition of soil sample taken from the upper layer of topsoil. High absorption of chemical substance is a characteristic for ...humus-organic layer of topsoil. The source of those substance could be a pollutant emitted to the atmosphere by human activity. The research area includes Upper Silesia region, which is the most industrial region of Poland. In the present study, the phase composition of the top soil separates were analyzed by using X-ray diffraction and Mössbauer spectroscopy. X-ray diffraction analysis revealed the presence of seven mineral phases in the material magnetic separated by lower current (quartz, illite, kaolinite, Fe3+ oxides, hematite, magnetite and pyrite). In case of higher current were identified four phases (quartz, muscovite, kaolinite and K0.94 Na0.06(AlSi3O8)). Mössbauer spectroscopy was used for an extensive analysis of iron-containing phases (pyrrhotite, magnetite, aluminosilicate oxides with Fe3+ and kaolinite/Fe2+ silicate).
Study of polymorphism is of great importance for the pharmaceutical industry once polymorphs may display different physicochemical properties, which, in turn, may result in stability differences that ...can bring problems for the manufacturing stages and the quality of final products. Although research on organic polymorphs has greatly increased in the last decades, it still does not cover all needs for the pharmaceutical market. Techniques such as spectroscopy in the infrared region, nuclear magnetic resonance, thermal analysis, X-ray diffraction, etc., can be used to identify polymorphism. The polymorphism is a property of the crystalline solid state, and can be evaluated by X-ray diffraction once each polymorph exhibits one specific X-ray diffraction pattern. The JST-XRD program is a tool designed to help the identification of crystalline phases (including polymorphs) present in pharmaceutical ingredients and tablets by using X-ray diffraction data obtained from scientific articles and patents. This paper presents new implementations for the JST-XRD and describes its use in the analysis of active pharmaceutical ingredient and marketed tablets of norfloxacin, mebendazole and atorvastatin calcium. By the means of comparison, JSTXRD allowed identifying the crystalline phases in the diffraction patterns of the analyzed drugs, showing the program suitability for polymorphism research, pre-formulation and quality control in pharmaceutical industries. JST-XRD can also be used for educational purposes in undergraduate and graduate programs in order to show the potentiality of X-ray powder diffraction in polymorphism analysis.
Since the discovery of X-rays at the end of the 19th century and the first works on diffraction of X-rays by crystals, huge developments were achieved in the application of these methods for material ...characterization. In particular, in the field of materials science and engineering, several applications were developed to become state of the art techniques. This chapter first presents a condensed overview of the production of X-rays as well as of the theory of diffraction of X-rays by crystals. A short survey of the hardware for X-ray diffraction (XRD) measurements is given. The methods of phase analysis, residual stress measurements, and texture investigations of polycrystalline materials are then described with examples, and finally, special methods and future trends are presented.
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