Critical evaluation of a putative glucosamine excretion by Aspergillus niger CBS120.49 and Penicillium ochrochloron CBS123.824 under citric acid producing conditions.

As one of the most frequently occurring monomers in the biosphere, glucosamine is a valuable metabolite for several applications. Although microbial glucosamine production is still in its infancy, it offers the possibility to circumvent problems associated with traditional production by hydrolysis. Of particular interest is a study with Aspergillus niger, which reports for the first time high glucosamine excretion in the early phase of citric acid production.

Optimization of an innovative vinylimidazole-based monolithic stationary phase and its use for pressured capillary electrochromatography.

A novel polymer monolith based on the dicationic crosslinker 3,3'-(hexane-1,6-diyl)bis(1-vinylimidazolium) bromide, the monomer 1-vinylimidazole and a ternary porogen mixture (1-propanol, decan-1-ol and water) was developed and optimized for capillary electrochromatography. This aim was accomplished by adjusting the composition of individual constituents in the polymerization mixture and monitored based on several relevant parameters (e.g.

Quantitative determination of major alkaloids in Cinchona bark by Supercritical Fluid Chromatography.

Chinoline alkaloids found in Cinchona bark still play an important role in medicine, for example as antimalarial and antiarrhythmic drugs. For the first time Supercritical Fluid Chromatography has been utilized for their separation. Six respective derivatives (dihydroquinidine, dihydroquinine, quinidine, quinine, cinchonine and cinchonidine) could be resolved in less than 7 min, and three of them quantified in crude plant extracts.

An innovative monolithic zwitterionic stationary phase for the separation of phenolic acids in coffee bean extracts by capillary electrochromatography.

A methacrylate based monolith, containing the innovative zwitterionic monomer (3-allyl-1-imidazol)propane sulfonate, was prepared in 100 μm I.D. silica capillaries by UV initiated photo-polymerization.

Quantitative analysis of mycosporine-like amino acids in marine algae by capillary electrophoresis with diode-array detection.

Marine species have evolved a variety of physical or chemical strategies to diminish damage from elevated environmental ultraviolet radiation. Mycosporine-like amino acids, a group of widely distributed small water soluble compounds, are biologically relevant because of their photo-protective potential. In addition, presumed antioxidant and skin protective strategies raise the interest for possible medicinal and cosmetic applications.

Quantitative Determination of Lactones in Piper methysticum (Kava-Kava) by Supercritical Fluid Chromatography.

A fast and validated supercritical fluid chromatography method for the quantitative determination of major lactones in , a plant used against nervous anxiety, stress, and restlessness, was developed. The baseline separation of dihydrokavain, demethoxyyangonin, kavain, yangonin, dihydromethysticin, and methysticin was possible in less than 4 min on an Aquity UPC BEH 1.7 µm column, in combination with a mobile phase comprising CO and methanol with diethylamine.

Determination of coumarins in the roots of Angelica dahurica by supercritical fluid chromatography.

The fact that supercritical fluid chromatography (SFC) offers many desirable features is known for a long time. Yet, the number of applications on natural products is still limited, because robust and user-friendly instrumentation became available just a few years ago. As coumarins hardly have been studied by this technique we developed the first SFC assay for their determination in crude plant material.