In liquid-liquid extraction processes, the mass transfer coefficient is one of the key design parameters. In the present study, the impact on mass transfer during droplet formation in a quiescent continuous phase is investigated analytically. Therefore, confocal Raman spectroscopy in a novel measurement cell combined with interfacial tension measurements are applied. It could be shown, that Marangoni effects in the system toluene-acetonitrile-water (mass transfer direction from the dispersed to the continuous phase) lead to 50% of mass transferred in the first 5s when 90% is transferred in 1min.