In experimental chemistry, quality assurance of research projects includes the documentation of procedures and results as well as the safeguarding of the materials obtained, insofar as this is possible and reasonable.<\/p>\n\n\n\n
Digital tools and methods are to be used whenever possible to document procedures, processes and observations. This includes the use of subject-specific software such as electronic laboratory journals for the digital recording of work processes and data. In particular, the results obtained must be proven beyond doubt. Spectroscopic, spectrometric and, if necessary, chromatographic methods are mainly used for this purpose. The choice of methods necessary for the unequivocal identification of substances will vary depending on the substance class and substance-specific requirements, but typically the characterisation methods described below should be used to substantiate the identification of new substances. The procedure used in the field of organic chemistry, inorganic chemistry and polymer chemistry is presented here by way of an example.<\/p>\n\n\n\n
Organic chemistry (molecular detection and characterisation):<\/strong><\/strong><\/strong><\/p>\n\n\n\n 1H NMR and 13C NMR spectroscopy, MS mass spectrometry (including high resolution), infrared spectroscopy, melting point or boiling point if applicable, elemental analysis, rotation value for optically active substances. For structural elucidation and in the case of uncertainty regarding signal assignment, evidence should be provided based on 2D NMR experiments such as 1H,13C correlation NMR spectroscopy (e.g. HSQC, HMBC) with signal assignment as complete as possible. Depending on the class of molecule and the presence of heteroatoms, further analytical methods such as heteroatom NMR (e.g. 19F, 31P, 11B) spectroscopy and UV\/VIS spectroscopy may be necessary. If it is possible to obtain crystals of the compounds obtained, X-ray structure analyses are to be carried out.<\/p>\n\n\n\n Inorganic chemistry (molecular detection and characterisation):<\/strong><\/strong><\/strong><\/p>\n\n\n\n If diamagnetic: 1H NMR and 13C NMR spectroscopy, MS mass spectrometry (including high resolution), IR spectroscopy, melting point if applicable, elemental analysis and rotation value for optically active substances. For structural elucidation and in the case of uncertainty regarding signal assignment, evidence should be provided based on 2D experiments such as 1H,13C correlation NMR spectroscopy (e.g. HSQC, HMBC) with signal assignment as complete as possible. Depending on the class of molecule and the presence of heteroatoms, further analytical methods such as heteroatom NMR (e.g. 19F, 31P, 11B) spectroscopy and UV\/VIS spectroscopy may be necessary. If it is possible to obtain crystals of the compounds obtained, X-ray structure analyses are to be carried out.<\/p>\n\n\n\n If paramagnetic: Single-crystal structure analysis, UV\/VIS spectrum, EPR spectrum, possibly paramagnetic NMR spectroscopy or characterisation by SQUID, MS, IR spectra.<\/p>\n\n\n\n Polymer chemistry (material detection and characterisation):<\/strong><\/strong><\/strong><\/p>\n\n\n\n 1H NMR and 13C NMR spectroscopy, IR spectroscopy. For basic structure elucidation and in case of uncertainty regarding the postulated molecular structure, evidence is to be provided based on additional suitable 2D NMR experiments. Depending on the class of molecule and the presence of heteroatoms, further analytical methods such as heteroatom NMR (e.g. 19F, 31P) spectroscopy and UV- VIS spectroscopy may be necessary. Gel permeation chromatography (GPC, with different detectors such as RI or UV) and MALDI-ToF or ESI mass spectrometry (depending on the average molecular weight) are to be performed to determine the average molecular weight. For absolute molecular weights, light scattering methods should be used. Thermal properties of polymers such as melting or glass transition points are determined by means of differential scanning calorimetry (DSC). Thermal stability is investigated by means of thermogravimetric analysis (TGA). If relevant for semi-crystalline polymers, X-ray structure analyses are to be performed.<\/p>\n\n\n\n For sustainable quality assurance, data arising in the research process should ideally be stored in open data formats that can be read using freely available software.<\/p>\n\n\n\n Captured measurement data should be stored at least in the original format of the measurement software. If the data format is proprietary, the data should additionally be stored in an open data (exchange) format that can be read using freely available software. Appropriate archives can be used to secure gained materials, e.g. substances examined or produced in the research process.<\/p>\n\n\n
In experimental chemistry, quality assurance of research projects includes the documentation of procedures and results as well as the safeguarding of the materials obtained, insofar as this is possible and reasonable.<\/p>\n","protected":false},"featured_media":0,"menu_order":0,"template":"","kommentar_cats":[267],"kommentar_tags":[283,191,238],"class_list":["post-6109","kommentare","type-kommentare","status-publish","hentry","kommentar_cats-natural-sciences","kommentar_tags-chemistry","kommentar_tags-documentation","kommentar_tags-quality-assurance"],"acf":[],"yoast_head":"\n