This article presents the results of experimental studies of spontaneous interfacial convection with the mass transfer in liquid-liquid extraction systems. For detection and characteristics of spontaneous convection experimental techniques was developed and tested, which allow the determining of surfactants local concentration on the interfacial surface. The paper contains a detailed description of the following detection methods: visual, kinetic, test of mass transfer, correlation spectroscopy and using of strong surface-active substances which are capable to suppress Marangoni convection. The developed techniques provide detection and receiving of interfacial convection characteristics