NMR IMAGING OF THE CHROMATOGRAPHIC PROCESS - DEPOSITION AND REMOVAL OF GADOLINIUM IONS ON A REVERSED-PHASE LIQUID-CHROMATOGRAPHIC COLUMN

NMR imaging permits the visualization of the adsorption processes whic h take place in chromatographic columns during the adsorption and conc entration of strongly retained analytes from their solutions in weak s olvents and during the desorption of these compounds as more concentra ted bands in a strong mobile phase. The results obtained demonstrate t hat the surface of stationary phases is not homogeneous and that colum n beds are not homogeneously packed. These deviations from an idealize d behavior must be taken into account in the interpretation of the res ults.