The temperature at the syringe was measured with a thermocouple and controlled via a PID controller (P6100, West Control Solutions, Brighton, UK). The syringe was kept at an elevated temperature to avoid supersaturation and to minimise the chance of nucleation and crystallisation occurring in the solution before reaching the cell. Over the course of the experiment, the solution was pumped into the crystallisation cell. The temperature at the inlet of the cell was again measured with a thermocouple to assure that the temperature was still high enough to avoid nucleation before the solution reaches the cell. This thermocouple was not connected to the PID controller and has been added only to monitor the system. Once the solution had passed through the cell, it flowed through the outlet at the bottom side to a beaker that was placed within the sample compartment of the terahertz spectrometer to collect the solution that was purged out.