CHROMATOGRAPHIC STABILITY OF SILICA-BASED AMINOPROPYL-BONDED STATIONARY PHASES

Causes of frequently observed changes in the properties of columns packed with silica modified with primary amino groups were investigated chromatographically, and it was confirmed that the initial instability of new columns appears to be due to the gradual desorption of the respective silane. Further changes in the chromatographic properties during the operation ensue from deactivation of the surface with impurities capable of reacting with the primary amino group. The main source of these impurities is the mobile phase. Simple prevention can be achieved with a protective column packed with the same sorbent and placed between the pump and the injection valve, which allows the column to be used for several months without changes in its chromatographic properties.