Optical emission spectrometry with inductively coupled plasma (ICP-OES)
Optical emission spectrometry with inductively coupled plasma and electrothermal vaporization (ETV-ICP-OES)
Measurement of optical rotation
We provide measurement and evaluation of infrared (IR) spectra, including their detailed interpretation. IR spectra could be measured by the transmission technique in solutions in cuvettes (most often from KBr) or in the solid phase in the form of pressed KBr tablets. Measurements in KBr tablets could also be performed by microtechnique which requires less than 1 mg of sample. All the mentioned measurements could be performed using reflectance techniques such as Attenuated total reflection (ATR) or Diffuse reflection method (DRIFTS). It is also possible to measure temperature-dependent IR spectra of substances in solution or in a tablet in the temperature range of 5-95 °C. The infrared spectrometer is also equipped with accessories enabling the measurement of aqueous solutions (transmission measurement in H2O or D2O, or the ATR technique can be used). Moreover, it is possible to combine infrared spectrometer with gas chromatography (GC-FTIR) which enables the analysis of volatile samples, including the identification of components in mixtures.
Raman microscopy enables the measurement of biological, biochemical and organic samples in the solid phase and in solutions. The Raman microspectrometer is equipped with a confocal and inverted microscope, an attachment for measuring the solution in standard cuvettes and an adapter for macro sample studies. There are five lasers with excitation wavelengths of 325 nm, 532 nm, 633 nm, 785 nm, 1064 nm. A polarization set is available for each laser which allows measuring of polarized Raman spectra to obtain additional information about the studied system (for example symmetry of vibrational modes, orientation of molecules). Accessories also allows the photoluminescence of a wide variety of compounds to be studied. Experiments can be performed on macro and/or microscopic samples including measurement of temperature dependencies (in the range of 5-95 °C). Microscopic samples such as living cells and monolayers can be studied and electrochemical experiments can be also performed.
Electronic circular dichroism (ECD) spectroscopy
Electronic circular dichroism spectroscopy is measured in the UV/VIS spectral range (180 nm – 800 nm) in solutions, solid samples and on layers at laboratory temperature. The linear dichroism could be measured when studying layers. It is also possible to measure temperature dependences (in the range of 5-95 °C). An absorption spectrum is measured in parallel to each ECD spectrum which is necessary to avoid artifacts in samples with low intensity or relatively high diffraction. Magnetic circular dichroism (MCD) can be studied at laboratory temperature using a permanent magnet (1 Tesla). ECD spectroscopy can be used to measure kinetics (including fast ones) and monitor equilibrium states in chiral systems. Furthermore, ECD spectroscopy can be used for conformational studies (especially of peptides, proteins, nucleic acids) and for determining the secondary structure of peptides and proteins. The ECD spectrometer also enables the measurement of fluorescence in solution and is also equipped with an attachment for stop-flow measurements.
Vibrational circular dichroism (VCD) spectroscopy
After previous agreement, it is possible to provide measurements of vibrational circular dichroism using the transmission technique in solutions or solids (pressed KBr tablets) at laboratory temperature.
Raman Optical Activity (ROA)
Raman optical activity can be measured in solutions at laboratory temperature.
Thermodynamic / kinetic solubility
There are two protocols generally used for the solubility measuring, the thermodynamic and the kinetic protocol. The first one can be defined as the concentration of compound in a saturated solution when the excess of solid material is in equilibrium with the solution at the end of dissolution process. The kinetic solubility is the concentration of a solution when the first precipitate appears after adding the highly concentraced solution of compound (most often using the dimethyl sulphoxide as a pre-solvent) in the solvent. The main advantage of the kinetic protocol is short time of sample preparation in comparison to the thermodynamical protocol. Although the thermodynamic protocol takes a longer time to reach equilibrium and is difficult to automate, it provides more accurate data because the solvent is not influenced by the other aditives such as dimethyl sulphoxyde.
The solubility measuring is performed using chromatographic system (Vanquish UHPLC, Thermo Fisher Scientific, Germany) connected to the diode array detector and consequently to the charged aerosol detector (both Vanquish, Thermo Fisher Scientific, Germany). Samples and calibration standards are prepared using automated system of robotic arm (PAL-RTC, Switzerland). This method is powerful in detecting possible impurities and measuring the solubility of the analyte of interest. The charged aerosol detector is a universal detector for non- and semi-volatile compounds. It also detects analytes with a lack of chromophore, such as steroids and its derivatives.
Differential Scanning Calorimetry (DSC)
Differential scanning calorimetry is a thermoanalytical method in which the difference between the amount of heat required to raise the temperature of a sample and a reference is measured as a function of temperature. Both the sample and the reference are kept at nearly the same temperature during the experiment. The method can determine the temperature and possibly also the enthalpy of phase transitions of the studied molecules. Indirectly, this technique can be used to control the quality and purity of substances. Therefore, it is also possible to use DSC for the development and research of materials, to identify and specify the possible polymorphic character of substances which can also affect the solubility of various forms (essential, e.g., for the bioavailability of substances).