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Lázně Bohdaneč, Czech Republic

Petrova Z.,Charles University | Jehlicka J.,Charles University | Capoun T.,Population Protection Institute | Hanus R.,Independent Gemmologist | And 2 more authors.
Journal of Raman Spectroscopy | Year: 2012

A commonly marketed handheld Raman spectrometer showed excellent possibilities in being used as a key instrument for unambiguous identification of gemstones mounted in the sceptre of the Faculty of Science of Charles University in Prague from the mid-20s of the 20th century. Numerous SiO 2 forms including chalcedonies intermixed with moganites (e.g. moss agates and carnelians), amethysts, citrines as well as garnets (pyrope-almandines) were identified. The estimation of the garnet type was based on obtained Raman parameters. The individual minerals constituting the lapis lazulis could not be discerned because of very high fluorescence they exhibited in the fingerprint region of the Raman spectrum, nevertheless the positions of the observed peaks in the 1000-2000cm-1 area were in very good agreement with the values of commercially available lapis lazuli pigment. The noble metals of the sceptre were studied by means of X-ray fluorescence analysis, which confirmed the presence of silver alloys and gilding. The comparison of silver alloys' semiquantitative analysis with the expected fineness, denoted by the hallmarks, indicated silvering. This has been later confirmed by the newly discovered restoration documentation. Portable handheld Raman and X-ray fluorescence instruments represent an ideal tool for studying historical artefacts, where an in situ investigation in museums or similar sites is obligatory. Copyright © 2012 John Wiley & Sons, Ltd. Source

Culka A.,Charles University | Jehlicka J.,Charles University | Capoun T.,Population Protection Institute
Journal of Raman Spectroscopy | Year: 2014

Selected amino acids (glycine, alanine, and threonine) were analysed in the form of water solutions, mixtures of these amino acids in solution, as well as their respective ices using two hand-held instruments under outdoor and winter mountain conditions. The hand-held instruments featured 785 and 532 nm excitations; the latter being one of the first using this wavelength on the market. The changes to the Raman spectra of the solutions and ices are discussed in relationship to the degree of ambiguity of the detection of the amino acids within the mixtures. The hand-held instruments were able to detect two amino acids out of the three in solution. The results showed that the hand-held instruments provide sufficient quality spectra when analysing ices prepared from the solutions; however, an unambiguous detection of these amino acids within mixtures still remains a challenge. Copyright © 2014 John Wiley & Sons, Ltd. Amino acids glycine, alanine, and threonine were analysed in the form of water solutions, and mixtures of solutions of these amino acids as well as respective ices using two hand-held Raman instruments (532 and 785 nm excitation) under outdoor and winter mountain conditions. Copyright © 2014 John Wiley & Sons, Ltd. Source

Jehlicka J.,Charles University | Vandenabeele P.,Ghent University | Edwards H.G.M.,University of Bradford | Culka A.,Charles University | Capoun T.,Population Protection Institute
Analytical and Bioanalytical Chemistry | Year: 2010

A handheld Raman spectrometer (Ahura First Defender) was tested for the unambiguous identification of biomolecules (pure amino acids, carboxylic acids, saccharides and trehalose) in the solid state under outdoor conditions (including moderate climate conditions as well as cold temperatures and high altitudes). The biomolecules investigated represent important objects of interest for future exobiological missions. Repetitive measurements carried out under identical instrumental setups confirmed the excellent reliability of the Raman spectrometer. Raman bands are found at correct wavenumbers ±3 cm-1 compared with reference values. This testing represents the first step in a series of studies. In a preliminary, challenging investigation to determine the detection limit for glycine dispersed in a powdered gypsum matrix, 10% was the lowest content confirmed unambiguously. Clearly there is a need to investigate further the detection limits of Raman spectroscopic analyses of biomolecules in more complex samples, to demonstrate the usefulness or disqualify the use of this technique for more realistic outdoor situations, such as eventual future missions to Mars. © 2010 Springer-Verlag. Source

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