Search

• Chromatographic separation of alkaloids from stem bark of Geissospermum vellosii. • Alkaloids characterization by UV–Vis DAD and HR Multistage MS. • Molecular structures of ten substances never previously been described. A number of analytical studies, started in the sixties of the last century, concerning the stem bark of Geissospermum vellosii, have documented the presence of a number of indole alkaloids whose molecular identity was defined by NMR technique. The potential bioactivity of these compounds has inspired more recent analogous studies either devoted to structural elucidation of new alkaloid molecules or to the investigation of the role of some of them in cancer therapy. Anyway, a complete fingerprinting of the bark content is still lacking. In this paper, after a suitable extraction step, we obtain a chromatographic separation showing a number of components higher than the number of alkaloids so far described. Considering the great number of substances present in the stem bark, their identification is practically impossible to reveal by NMR techniques. As we presume that there are other stem bark unidentified alkaloids with important bioactivity, we propose to characterize their molecular structures by UV–Vis Diode Array spectrophotometry and High-Resolution Multistage Mass Spectrometry. The two adopted detection techniques were first tested on the already known Geissospermum vellosii molecules, and, after an inspection of their efficacy, were applied to the substances that have not yet been described. Herewith we propose the molecular structures of 10 substances that were never previously described, and in addition we provide experimental evidence of the presence of 6 already known substances which were never reported in the Geissospermum genus. A far more detailed description of the bark constituents is therefore provided. [ABSTRACT FROM AUTHOR]

The purpose of this study was the development of various analytical mass spectrometry (MS) methods to investigate the chemical composition of e-liquids used in electronic cigarettes and characterize their quality. Low-quality nicotine (the main active compound), glycerol, propylene glycol (solvents), or flavors could greatly increase the toxicity. The search of alkaloid contaminants of nicotine was performed by liquid chromatography-tandem mass spectrometry (LCMS- MS) after a study of fragmentation pathways by high-resolution electrospray ionization (ESI)-MS. A fully validated method for quantitation of organic polar impurities such as cotinine, anabasine, myosmine, nornicotine, and N-nitroso-nornicotine and nicotine itself was developed using MS coupled to ultrahigh-pressure liquid chromatography (UHPLC). To evaluate organic volatile toxicants, the headspace from e-cigarette refill liquids was sampled by the purge-andtrap method to perform gas chromatography (GC)-MS analysis. Finally, heavy metal residues as inorganic toxicants were determined by inductively coupled plasma (ICP)-MS after simple dilution. A number of cases of contamination by metals (mainly arsenic) were detected. [ABSTRACT FROM AUTHOR]