Chemistry

Identification and quantification of compounds and crystal phases present in the sample

Use of powder X-ray diffraction to identify and quantify crystal phases present in the sample and formed by inorganic and organic compounds. Phase identification is performed using PDF-2 and COD databases. In cases all the phases in the sample can be identified and their crystal structure information is available, it is possible to determine the phase composition using the Rietveld refinement. 

Agris Bērziņš
(agris.berzins@lu.lv; +371 28348745; https://www.kf.lu.lv/en/about-us/chairs/chair-of-physical-chemistry/)

Screening of polymorphs, hydrates, salts and co-crystals of pharmaceutical substances and other organic substances

Screening of crystal forms (polymorphs, hydrates, solvates) of active pharmaceutical ingredients by crystallization under different conditions as well as exposing the substance to different humidity and temperature. Screening of salts and co-crystals formed by the substance by crystallizing the substance with various acids, bases or co-formers. Identification of the most stable crystal form. Characterization of the preparation conditions and stability of selected crystal forms. Phases are identified by PXRD and characterized by DSC, TG and DVS methods.

Optimization of the crystallization process of pharmaceutical substances and other organic compounds

Characterization of the crystal phase by DSC, TG and DVS methods and determination of its formation conditions. Exploration of the crystallization process and determination of the optimal preparation conditions (crystallization technique, temperature regime, solvent). Determination of the purity of the obtained crystallization product.

Determination of thermal properties of compounds and characterization of transformations

Determination of such thermal properties of a substance as melting and phase transition temperatures as well as heat capacity and glass transition temperature of amorphous phases using the differential scanning calorimetry (DSC) method. Determination of weight loss upon heating using the thermogravimetric (TG) method. Characterization of substance transformations using these thermal analysis methods.

Characterization of water and other solvent vapor sorption-desorption properties of sample

Measurement of water vapor sorption-desorption isotherms of sample (characterization of mass changes at different relative humidity). Sorption-desorption measurements of vapors of other volatile solvents are also possible.

Differential thermal analysis (DTA) and thermogravimetry (TG)

The DTA/TG method accurately determines the melting point of the test substance and simultaneously analyzes phase transitions, mass changes, and chemical transformations that occur when the sample is heated (or cooled). The decomposition temperature of a substance can be determined. It is also possible to approximately determine the content of sorbed water (all volatile components) in the sample, which is especially important for the analysis of materials that easily absorb water and for which, for example, it is necessary to provide, for example, appropriate storage conditions.

X-ray fluorescence spectroscopy (XRF)

X-ray fluorescence spectroscopy is a simple and convenient method for detecting and quantifying elements with mass number Z>10 (sodium and heavier elements) in solid and liquid samples. It is possible to determine the composition of almost all elements in a sample simultaneously with good accuracy, and it is also possible to determine the elements in a sample with concentrations up to ppm. The main advantage of the method is that it is fast and does not destroy samples. Sample preparation in most cases is very simple (often not needed).

Powder X-Ray Diffractometry (PXRD) Analysis

Powder X-ray diffractometry is a fast, efficient and non-destructive method for the phase identification and quantification of solid powder samples. The method makes it possible to identify, for example, the composition of building materials or polymorphic forms of pharmaceutical substances.

Inductively coupled plasma mass spectrometry (ICP-MS)

ICP-MS is a highly accurate, sensitive and reliable method for the determination of metallic and some non-metallic elements in various samples. ICP-MS is particularly suitable in cases where the concentration of the analyzed elements in the sample is very low.

Testing of polymer and polymer compsite stress-strain, thermal and structure properties and evaluation of  the results, modifications

Production of polymer composites, concentrates, dispersion of nanoparticles, collection and analysis of the results of the strength of composite materials, thermal properties, structural analyses, availability of universal tensile testing machine, possible consultations on modeling optimal properties, possible modification of materials by chemical methods, UV radiation, ionizing radiation (sterilization, crosslinking).

Ingars Reinholds
(ingars.reinholds@lu.lv; +371 26802448;   https://www.kf.lu.lv/en/about-us/chairs/chair-of-inorganic-chemistry-and-labour-protection/)

Identification of volatile compounds in samples of different origin

The identification of volatile organic and inorganic compounds is carried out using gas chromatography in combination with mass spectrometric detector. Different kinds of liquid as well as solid samples (water, soils, fuels, solvents, dyes, fragrances etc.) can be used for analysis. The identification is based on the separation of the mixture inside the capillary gas chromatographic column and subsequent comparison of the acquired masspectra of individual compounds to the masspectra collected in the NIST 2008 database. In cases when complex mixture has to be analysed, a method for the separation of interferences can be developed as well as different sample preparation procedures can be applied.

Antons Podjava
(antons.podjava@lu.lv; +371 27629296; 
https://www.kf.lu.lv/en/about-us/chairs/)

Identification and quantification of compounds in the sample by LC-DAD/MS

Liquid chromatography with a diode array and mass selective detector (LC-DAD/MS) is used to identify and quantify the compounds in the sample. The obtained data can be used to provide information on the molecular weight, structure, and abundance of specific sample components in a variety of sample types: biological fluids, foods, pharmaceuticals, environmental, and other samples. The identification of compounds is based on the comparison of the acquired mass spectrum with data of the standard substance and mass spectra in open access databases or literature.

Stable and radioactive isotope analysis

Analysis of stable isotopes in water and solid samples. Sample collection, analysis and report preparation.