The cuvette designed for flow-through measurements was purchased from Hellma and it had 4 polished windows with 2 optical path lengths; 3 mm and 1.5 mm. Center height (z) was at 8.5 mm. It had 35 mm x 12.5 mm x 12.5 mm (height x width x depth) outer dimensions, and the cell material consisted of quartz glass Suprasil. Aperture height and width for 1.5 mm path length was 11 x 2.5 mm. It had a cell volume of 50 µL. This flow cuvette was placed in the cell holder of DLS instrument such that the path length was set to 1.5 mm. Preliminary transmittance and particle size measurements were performed for the flow cuvette to study its best performance in the system and it was found that, at 1.5 mm optical path length, the transmittance was 100%, while at 3 mm path length, it was 0.2%. Hence, 1.5 mm path length of the cuvette was set up for all the particle size measurements. Disposable cuvettes / plastic cuvettes and omega cuvettes were not suitable for this experimental setup, because the cuvette material reacted with organic solvents and caused degradation of the cell material.