The measurements are conducted with a 2 mol/L toluene in tetrahydrofuran (THF) solution. By simultaneous using 3/2-way valves V2 and V4 in front of the inlet T-piece, switching between toluene solution and pure THF is possible while pumps are running. A concentration change is generated at the reactor inlet as a signal either by introducing the toluene solution into the THF filled reactor cartridge or by displacing the toluene solution from the reactor by using pure THF. Flow rates used are 2 mL/min utilising Postnova syringe pumps unless otherwise specified. The incoming signal is detected at the reactor outlet and recorded for further evaluation.