Complexation between the linear maltodextrin oligosaccharides and certain enantiomeric compounds of pharmaceutical interest in buffered solutions can lead to an analytically desirable chiral recognition. Different maltodextrins were assessed in their capacity to cause enantiomeric separations under various conditions of capillary electrophoresis. The mechanism of chiral recognition has been probed through electrophoretic mobility and selectivity measurements for different buffer solutions and organic solvent additives. A differential interaction of chiral solutes with the maltodextrin helical entities emerges as the basis of such enantioselectivity. This notion is further supported by 1H- and 13C-NMR experiments. Optimized separations of simendan, ibuprofen, warfarin, and ketoprofen enantiomers are demonstrated together with a chiral determination of ibuprofen in a blood serum sample at the therapeutic level.

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Extensive multimer formation of small and uncharged analytes was observed in electrospray mass spectrometry. The concentration-dependent aggregation behavior, including species up to tetramers, resulted in highly nonlinear calibration curves. For some analytes, these effects were operating down into the nanomolar level. Varying the drift potential failed to selectively dissociate the multimer complexes in favor of the monomer, which severely obstructed quantitative work. However, by incorporating certain cationic additives into the electrosprayed solution, complete suppression of the multimers could be obtained. In addition, a gain in the signal intensities by a factor up to 7 was achieved. A variety of additives were investigated, and the structural requirements for optimum performance will be outlined.

The fluorescent derivatives of complex oligosaccharide mixtures from different origins are separated in open capillaries. The number of negatively charged sulfonate groups in the tag molecule strongly affects separation efficiency and selectivity. Coating of the capillary surface with linear polyacrylamide has been essential to ensure fast and stable migration velocities. Efficiencies in excess of 1 million plates/m have been achieved, facilitating resolution of branched oligosaccharides. The effects of field strength and buffer composition on the apparent electrophoretic mobility of dextran and dextrin oligomers are discussed, with relation to borate complexation. Preliminary examples of applications to monitoring the action of hydrolytic and synthesizing enzymes are also described.

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