While the use of the programmable syringe pump allowed for an increase in amplitude, only lower oscillation frequencies could be realized. The oscillating flow conditions did not lead to an improvement in selectivity (figure ). Regardless of Re0, the selectivity remained at about 80 %. Even though that the same Re0 range was accessed as with pump D, the selectivities obtained with the syringe pump were lower. Since only the relation between the amplitude and the frequency of the pulsation was changed, it can be assumed that in the reactive case the influence of the amplitude on the selectivity is more pronounced than the effect of the frequency. Thus, Re0 does not seem to be the best suited indicator for the realized flow conditions in a reacting magnesium bed. The interaction of these two parameters is hidden.