The complexation kinetics of palladium(II) with 2-(5-bromo-2-pyridylazo)-5-diethylaminophenol (5-Br-PADAP) at the heptane-water interface was investigated by resonance Raman spectroscopy combined with a centrifugal liquid membrane method. It was demonstrated that this method was advantageous for the kinetic studies of complex formation proceeding at the liquid-liquid interface.