Separation of drug substances by modern liquid chromatography on silver impregnated silica gels.

The use of silver halide impregnated supports for high-pressure liquid chromatographic (HPLC) and thin-layer chromatographic (TLC) analysis of drug substances has been studied. Successful separations of xanthines and mixtures containing barbiturates, xanthines, ergot alkaloids, and tropane alkaloids have been achieved with isocratic conditions or by using simple gradients. The Ag-supports show a similar behavior as many chemically bonded stationary phases, such as modification fo adsorption sites on silica gel to give lower retention but better specificity; rapid reconditioning in connection with gradient elution (3-5 minutes). Reasonable cost, simplicity of preparation and usage, and good chemical and physical stability render the silver halide phases applicable in routine analysis and quite competitive with many commercially available chemically bonded stationary phases.