Cholesterol detection using C18-separation and ion trap analysisAlena Dreiling, Simone Königpp 273-276Abstract:A method was developed for the analysis of cholesterol using capillary reversed-phase liquid chromatography coupled to positive ion electrospray mass spectrometry. In contrast to UV at 214 nm, where detection was not very sensitive (10-20 pmol limit), targeted MS/MS on the dehydrated cholesterol ion allowed specific detection at the low pmol/high fmol level.Beta-mercaptoethanol artifacts in protein analysisMalte Bayer, Simone Königpp 277-289Abstract:A modification with β-mercaptoethanol was detected in commercial purified proteins, synthetic peptides, expressed proteins and proteins isolated from various sources. It results from the use of this agent at some point during sample preparation even though the later user may not be aware of it. The artifact affects, nevertheless, subsequent analyses. Cysteins occupied in mixed disulfides are not available for other activities or chemistry such as disulfide bridges and cross-links. They are stable unless reducing conditions with e.g. dithiothreitol are maintained throughout the workflow.Composition and activity of Vitex Agnus CastusSimone Königpp 291-312Abstract:The shrub Vitex agnus castus (Vac) has been used in folk medicine as a remedy for various obstetric and gynecological disorders for thousands of years. Structural analysis of the natural compounds in Vac extracts identified a number of potential bioactive compounds such as casticin and agnuside. Studies showed binding of Vac components to estrogen and dopamine receptors. This review summarizes the analytical efforts to date discussing the substances isolated and the bioactivity tested as well as applications.
Dec. 5, 2014pp 313-334