![]() Of course, these data can be of experimental origin, however, it can also be an indication for faked values (especially in the case of a large number of perfectly fitting analyses). About 5–10% of the publications show elemental analysis data where most or all values deviate ≤0.10% from the theoretical calculation. We checked the deviation of theoretical and experimental elemental analysis values in several issues of bioinorganic and general chemistry journals. ![]() Based on our experience as reviewers in various peer-reviewed journals, there are more and more manuscripts/publications, where the presented values are so perfect that it is extremely hard to believe that real values were actually measured. However, this is where the problems begin. This is essential for all subsequent biological, catalytical and analytical studies, which rely on this information for their accuracy. of Organometallics, 2 Angewandte Chemie, 3 Chemistry – A European Journal 4). Usually, the measured values have to fit the gold standard of ± 0.40% of the calculated values to guarantee sufficient purity (see author guidelines e.g. Also, in case of multidisciplinary journals like Angewandte Chemie, Journal of American Chemical Society, Chemical Science, Chemistry – A European Journal, etc., this analysis is mandatory for synthetic (bio)inorganic chemistry. Inorganic Chemistry, Inorganic Chemistry Frontiers, Organometallics, Dalton Transactions, Journal of Inorganic Biochemistry, Journal of Biological Inorganic Chemistry, and many more, elemental analyses of newly synthesized compounds are a requirement for publication. Thus, in peer-reviewed international (bio)inorganic chemistry journals e.g. A likely explanation is that characterization of the subclass of paramagnetic compounds by NMR spectroscopy is not meaningful. Reviewing elemental analysis data In contrast to synthetic organic chemistry, elemental analysis is an essential part of substance characterization in the field of (bio)inorganic coordination chemistry. rate constants (catalysis), biological data (medicinal chemistry) or material properties. As a consequence, this will generate wrong results when comparing e.g. Inorganic salts like NaCl derived from insufficient purification protocols or co-crystallized water molecules cannot be detected by NMR spectroscopy or HPLC, which easily can lead to errors of about 10–20% in the molar mass. This is the feature that makes elemental analysis unique among characterisation tools. Nevertheless, these values allow conclusions about the elemental composition and as a consequence the purity of compounds. It delivers only a few values which show little compared to the large amount of information generated from e.g. Of course, elemental analysis seems to be a rather crude technique leading to nothing more than an empirical formula. 1 The typically analysed elements are carbon (C), hydrogen (H), nitrogen (N) and sulfur (S), rarely also oxygen (O) is measured.Īfter the invention of mass spectrometry, the introduction of high performance liquid chromatography (HPLC) and the rise of nuclear magnetic resonance (NMR), the importance of elemental analysis in synthetic organic chemistry declined (in contrast to (bio)inorganic chemistry). Fritz Pregl compiled the methods after adapting them to consume as little as a few milligrams of material for one analysis and founded Organic Elemental Microanalysis (OEM, or simplified: elemental analysis). The advancement of organic chemistry (identification of natural substances as well as synthetic approaches) was based on the information about the composition and the molar mass of chemical compounds. It has provided essential information about substances and their composition from the beginning of the development of chemical concepts and science in general. ![]() Introduction Elemental analysis marks the origin of chemical understanding. This would enable reviewers, editors and readers to better judge the presented results in the future. Within this article we discuss what realistic measured deviations from the theoretical composition of a compound are and present an approach to provide original elemental analysis data to support the listed values in the experimental sections. Our personal observation in the review process of numerous manuscripts over the last years revealed that the amount of questionable data is constantly increasing. ![]() with chromatograms, making this essential analysis prone to manipulations. However, in contrast to other analytical methods, there is no requirement to prove the presented values e.g. Elemental analysis provides a powerful analytical tool for purity determination of compounds and is a prerequisite for publication in many journals dealing with (bio)inorganic synthetic chemistry.
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