Separation and determination of neuraminic acids in nanogram quantities by liquid chromatography — A comparative study with different amino phases

Summary Neuraminic acid derivatives were separated easily by liquid chromatography on amino phases and using acetonitrile/15 mM phosphate buffer, pH 5.2 as mobile phase. Detection at 200 nm allowed determination of substances in the nanomole range. All solvent systems were used isocratically at room temperature. The separation did not depend on ion-exchange but on a partition mechanism, the solutes being separated according to their polarity. Thus, it was possible to optimize the resolution by varying the stationary phase and the composition of the eluent.Part of this work has been presented at the 15th International Symposium on Chromatography, Nürnberg, October 1–5, 1984.     

Antimicrobial Sol–Gel Coatings

The preparation and the releasing behavior of modified silica coatings, containing embedded biocides on textiles, were compared and assessed with regard to application parameters like antimicrobial efficacy, wash-out and long-term behavior. For this, silica layers with embedded silver, silver salts and biocidal quaternary ammonium salts (cetyltrimethylammoniumbromid and octenidine) were investigated. Both the growth of fungi and bacteria can be inhibited by coatings with embedded biocides. Especially by using octenidine, an excellent long-term inhibition of fungi growth can be reached.     

Coulometric microdetermination of peroxides-II: organic peroxides

An iodometric method for the rapid microdetermination of organic peroxides, utilizing electrochemical reduction in the iodine-iodide system, has been developed. After complete reaction between peroxide and iodide in an acidic semi-aqueous medium the iodine produced is reduced at a rotating platinum electrode, at constant potential. Electronic integration is used. Organic peroxides of different reactivities have been analysed by making use of the increased rate of reaction at elevated temperatures. Accurate and precise results were obtained for samples at the 1-mg level and the total time of analysis varied from 8 to 20 min, depending on reactivity.