3. After a very long time, the surfactants are only mildly depleted from the aqueous phase with a concomitant increase of the surfactants in the organic phase and a slight increase of oil in the aqueous phase (Figure (C and D)). All these concentrations are eventually re-equilibrated following which DDA and oil virtually disappear from the aqueous phase. The other quartz cuvette (LAB4US UV Quartz Cuvettes, 10 mm path length from fisher scientific, USA) was used to study the evolution of the concentration of the surfactant as it diffused from the aqueous to the organic phase as well as the evolution of the concentration of oil and surfactant in the aqueous phase. An organic liquid (2.2 ml) was gently deposited above 2.2 ml of 0.6 M salt solution inside the cuvette (Figure ). The height of the quartz cuvette was so adjusted inside the spectrometer sample holder such that the UV beam passed either above the interface of the two liquids, as shown in the self-explanatory schematic (Figure ). The UV beam passing through the organic phase monitored the concentration of surfactant as it diffused from the aqueous to the organic phase.