Simultaneous determination of inorganic anions and cations by capillary electrophoresis with indirect UV detection.

The development of a separation system for the simultaneous determination of inorganic anions and cations, low-molecular-mass organic acids and aliphatic amines by capillary electrophoresis with indirect UV detection using new electrolyte systems is described. Different principles of the experimental enforcement are compared. The principle of both-side injection was investigated using two different electrolyte systems. In order to avoid system peaks caused by the presence of different electrolyte co-ions, the selection of useful electrolyte components is more difficult than the choice of electrolytes for separate anion or cation analysis and special preparation procedures are necessary. The applicability of the method is shown by investigations of reproducibility, linearity of the calibration and by the analysis of drinking water including a comparison with results of measurements carried out with atomic absorption spectrometry for the cation determination, and ion chromatography for the anion determination.

Separation of water-soluble vitamins via high-performance capillary electrophoresis.

A standard sample and method for performance evaluation in capillary zone electrophoresis is defined. The sample, containing thiamine, nicotinamide and nicotinic acid, was analysed in a 20 mM sodium phosphate buffer pH 7. The impact of pH, buffer type and ionic strength on electroosmotic flow, electrophoretic mobility, and peak shape was investigated. The separation of several water-soluble vitamins in phosphate buffer pH 7 was developed in order to analyse an over-the-counter vitamin preparation. Spectral analysis and peak purity tests were applied on-line for peak identification.