Elektrochemischer Detektor mit einer Kohlefaserbündel-Arbeitselektrode für die HPLC

HPLC-Electrochemical Detector with a Carbon Fiber Working Electrode The paper describes an electrochemical detector with carbon fibers as the working electrode placed perpendicularly to the flow direction. The detector performance was characterized by the detection limit for selected phenolic compounds, reproducibility, linearity and the signal dependence on the flow rate. An electrochemical in situ pretreatment of the working electrode improves sensitivity and long term stability.     

Polymere für die separation mit membranen

The separation with membranes has made evident progress. The knowledge of permeation through membranes is well established, even the process design and development of technical application has reached a high level. This is above all the result of intense search for new polymers suitable for the production of more efficacious membranes, but last this could succeed in the introduction of new membrane forming procedures. The now used and promising polymers for membranes are discussed to the respective separation processes hyperfiltration, ultrafiltration, dialysis and gaspermeation.     

Modellierung der Trocknungsdauer für die dynamische Gefriertrocknung

During dynamic freeze drying, the dry layer is permanently rubbed off, which results in an increase in drying performance. By means of the experimental determination of the heat transfer coefficients in dependence of some process parameters (rotational frequency, loading, drying temperature), the heat transfer coefficient can be interpolated by means of the presented model and from this the drying time can be determined. Milk spheres, milk pellets and starter culture of the strain Pediococcus pentosaceus were used as model systems.     

Möglichkeiten der Fettchemie für die Schmiermittelindustrie

Feasibilities of the Fat Chemistry for the Lubricant Industry Animal and vegetable fats and oils have been used for centuries as lubricants. Only the industrialization and motorization led to an immense increase of the consumption of the lubricants which amount today about 1.3 million tons a year only in the Federal Republic of Germany. The mineral oil represents now the most important raw material. Therefore the question arises what contribution the fat chemistry can give today for the lubricant industry to accomplish its various tasks. Feasibilities of the fat chemistry to refine oils and fats furtheron to suitable formulation components for the lubricant industry are pointed out. Thereby actual problems and development tendencies are discussed, which are correlated with the matter of lubricants and are nowadays generally discussed.