A column filled with a 2.6 µm core-shell particle will have a smaller column dead volume as the same column dimension filled with a similar sized fully porous particle. The column dead volume is reduced about 10 - 15%. The dwell time of substances is varying because of the shorter diffusion path.
Due to the lower backpressure and the reduced column volume the used flow rate could be increased but therefore the gradient steps have to be readjusted.