Analysis of colloids VIII. Concentration and memory effects in size exclusion chromatography of colloidal inorganic nanometer particles

Abstract

Colloidal cadmium sulfide with diameters of ca. 17 nm was used as a model substance to study the effects of sample concentration on elution time and peak area in size exclusion chromatography SEC of colloidal inorganic particles in the low nm size regime. A clear distinction had to be made between the pure particle concentration and that of the accompanying electrolytes. The effects were astonishingly high taking into account that particles and small electrolytes are separated immediately in SEC. The reasons for these phenomena are discussed. The electrical double layer was found to play an important role. The results obtained for solid particles were compared with those for organic polymers in SEC. A memory effect of the column was observed due to temporarily adsorbed particle