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Biomedical subjects

J Schiewe

Publications and source records attributed to J Schiewe.

4 recordsLinked to original sources
PubMed1997

Application of capillary zone electrophoresis in cephalosporin analysis.

Cephalosporins have structures and antibiotic activity similar to those of penicillins which represent a class of compounds with closely related structures. Most of the cephalosporins contain aromatic groups and show distinctive UV spectra. Separating the different types of cephalosporins is a challenging task for HPLC. but the resolving power of capillary zone electrophoresis (CZE) makes this separation fast and simple. The present study reports the application of CZE for cephalosporin analysis and the separation of cephalosporins from plasma. Both field strength and temperature were shown to influence the plate number. The influence of injection time on the peak height was studied. Furthermore, the influence of pH value on the separation of cephalosporins by CZE was investigated. The low sample amount required and the relatively short analysis time are the main advantages of this method.

Cefotaxime↗
PubMed1997

Capillary zone electrophoresis in skin fatty acid analysis.

The development of a method for analyzing C12-C18 fatty acid alkali salts by capillary zone electrophoresis is described. Organic solvents were added to the aqueous separation buffer to achieve solubility of the fatty acids together with higher temperatures. Detection of these poorly UV absorbing species could be achieved by indirect photometric detection adding a highly UV absorbing co-ion to the separation buffer. Thus detection limits of 6 microM were recorded. The dynamic range of quantitation was limited to 10(1) due to association and micelle formation at higher concentrations. The relative standard deviation of the method was in the range of 4 to 10%. The described method could be successfully applied to the analysis of free fatty acids in human stratum corneum after solid phase extraction of the lipid fraction.

Calibration↗
PubMed1996

Application of capillary zone electrophoresis for analyzing biotin in pharmaceutical formulations--a comparative study.

The detection limit and reproducibility of capillary zone electrophoresis (CZE) measurement of biotin were compared to those of a spectrophotometric method and those of the determination of the sulphur content by combustion of the biotin sample followed by coulometric titration of the formed SO2. Drug analysis showed that all three methods gave consistent results and were suitable for the determination of biotin. CZE was found to be the best method for the determination of pharmaceutical formulations containing biotin because of its high separation efficiency, short analysis time, ease of instrumentation and sample preconditioning, and good precision.

Biotin↗