Enantioseparation of glutethimide and its 5-OH-metabolite in capillary electrophoresis and study of selector-selectand interactions using one-dimensional rotating frame nuclear Overhauser and exchange spectroscopy

Enantioseparation of glutethimide (GT) and its 5-hydroxy metabolite (5-OH-GT) has been studied with several charged cyclodextrin (CD) derivatives. The emphasis was made on the enantiomer migration order of GT and simultaneous enantioseparation of GT and 5-OH-GT. The possible structural differences of GT complexes with three different single isomer charged CD derivatives were studied using one-dimensional rotating frame nuclear Overhauser and exchange spectroscopy (1-D ROESY).     

Isobar configurations in closed shell nuclei

Explicit expressions for one- and two-N¹ isobar configurations in closed shell nuclei have been derived in the impulse approximation and applied to ⁴He and ¹⁶O. Conventional transition potentials with π- and ?-exchange have been used and the influence of potential regularization and short-range correlations have been studied. The dominant isobar configurations are found to be the one- and two-Δ components and originate from two-nucleon pairs in a relative S-state. The probability for finding a nucleon as a Δ-isobar is about 4.5% in ⁴He and about 3.2% in ¹⁶O. These numbers should be considered as upper limits due to uncertainties in off-shell effects of the transition potentials.