The impact of mass transfer in liquid-liquid extraction during droplet formation in a quiescent continuous phase was investigated. The impact of droplet size, concentration, and formation rate on a hanging droplet was analyzed via laser induced fluorescence (LIF) using rhodamine 6G as tracer in the system of toluene and acetone in water. The droplet formation rate has a major impact on mass transfer and the mixing pattern inside the droplet. Very fast mass transfer induced by Marangoni convection was visualized at a high local resolution independently of concentration and formation rate.